Don't store Oxygen and Acetylene together in an LPG bottle and attempt to weld - Page 1
Forum section: electronics / general

author: Psi
author_rank: Super Contributor
timestamp: September 05, 2018, 10:55:09 pm
content: Pretty self explanatory, really,https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12119555

author: TerraHertz
author_rank: Super Contributor
timestamp: September 05, 2018, 11:14:07 pm
content: Wow, ignorance and stupidity brings us another instant Darwin Award winner.

author: BradC
author_rank: Super Contributor
timestamp: September 05, 2018, 11:33:26 pm
content: Quote from: TerraHertz on September 05, 2018, 11:14:07 pmAccording to the article he had a 15 year old daughter, so he not qualified for a Darwin.

author: m3vuv
author_rank: Super Contributor
timestamp: September 06, 2018, 12:41:02 am
content: god what a plonker!

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 01:28:46 am
content: Yeash! Compressed acetylene is dangerous enough on its own*, mixing it under pressure with oxygen is quite simply suicidal. I'm not one for needless rules and regulations but acetylene is one of those things that you ought not to be able to buy without a licence that proves you have adequate training to store and use it safely.*For those not in the know, it's quite possible for an acetylene cylinder to turn into a bomb all on its own, with surprisingly little provocation. If it isn't in a specialist acetylene cylinder (where it's actually stored absorbed in a solvent and/or a porous matrix) a sound hammer blow to the cylinder can be sufficient to detonate it. Even with a specialist cylinder an otherwise trivial fire may be enough to get a cylinder of acetylene to 'cook off'.

author: amyk
author_rank: Super Contributor
timestamp: September 06, 2018, 02:21:03 am
content: Ironically enough I was reading an old welding book recently, where they certainly knew and discussed the dangers of pressurised acetylene and its tendency to detonate...over 100 years ago.

author: coppercone2
author_rank: Super Contributor
timestamp: September 06, 2018, 02:26:55 am
content: I want to know his idea of how chemical reactions work. I blame the school system honestly.Does he think the flame front is going to move at like a snails pace and be pushed out? Can't he tell how it works every time he ignites a torch? It seems intuitive.Maybe they never had a bunsen burner in his class room. I could see this happening if he read about flame in a text book and never ever saw a gas burn before.

author: alpher
author_rank: Frequent Contributor
timestamp: September 06, 2018, 02:29:26 am
content: Nobody stores acetylene in liquid/or gaseus form in pressurized cylinders.The story as presented holds a little water, as even the almost fully discharged oxygen bottle has a pressure that almost certainly is bound to burst your run of the mill propane bottle.

author: Ian.M
author_rank: Super Contributor
timestamp: September 06, 2018, 03:06:59 am
content: Propane cylinders can operate at up to 320 PSI, and their burst pressure is much higher than that, so its not unreasonable that an idiot could put a significant pressure of oxygen into one.Also acetylene forms explosive compounds with copper and several other transition metals that are extremely sensitive detonators (to the point that they are too sensitive for practical use) and has the widest range of explosive limits of any commonly used gas{ref}.You absolutely do not re-purpose other valves, fittings, regulators, hoses or piping for acetylene due to the risk of explosive metal acetylide formation. That's probably what finally triggered the timebomb the deceased had constructed. He probably got away with it initially because there was no metal acetylide buildup. Leave it a while then move any part of the improvised valvegear and a detonation was the most likely outcome.Acetylene cylinders need that porous packing to break up the volume of the headspace enough so that if it starts decomposing in one pore, there isn't enough energy released to overcome the small activation energy barrier and start decomposition in an adjacent pore. Without the packing or some other means to rob energy from the reaction quickly enough (e.g. cold walls of a narrow bore pipe) decomposition propagates explosively. The *ONLY* place its permissible to have acetylene gas at a pressure above 15 PSIG is in the pores of the packing in the headspace of the cylinder, and in the short narrow passages of the cylinder valve and acetylene regulator. *ANY* impact that causes the cylinder to 'ring' enough to compress the packing is a really bad idea - if the culmunitive damage compresses the packing enough to open up a significant void, you've then got a timebomb sitting thereAs for the level of stupidity involved in mixing *any* fuel gas with oxygen under pressure in a cylinder - well I don't understand how the deceased made it to the age of 39 without getting killed off by some other hazard. To even contemplate mixing acetylene and any oxidiser other than at the tip of a purpose designed and properly maintained acetylene torch or burner is just plumb crazy.

author: james_s
author_rank: Super Contributor
timestamp: September 06, 2018, 04:47:37 am
content: Quote from: Cerebus on September 06, 2018, 01:28:46 amI for one am glad that I can buy acetylene without jumping through a bunch of legal hoops. Millions of people have oxy acetylene rigs and incidents like this are extremely rare. You can't ban everything someone could possibly blow themselves up with. I'd be willing to bet that a lot more people are injured by improper use and storage of gasoline/petrol than acetylene and absolutely anyone can buy that.

author: KL27x
author_rank: Super Contributor
timestamp: September 06, 2018, 06:20:39 am
content: Where did he get acetylene and oxygen gas under pressure? The guy must have had access to proper acetylene and oxygen bottles to begin with. As well, you figure he had a proper acetylene torch. And if he had gotten it to "work," already, why is he removing the regulator to get the torch to connect, there at his friend's house?I think the writer confuses the function of a regulator with flame arrestor, but that's another problem.It's sad this happened. Super tragic that his friend recognized the danger but couldn't talk him out of it.QuoteI can see how you can acquire this stuff without really understanding how it works, I suppose. Then one thing leads to another.

author: hendorog
author_rank: Super Contributor
timestamp: September 06, 2018, 06:40:32 am
content: Quote from: KL27x on September 06, 2018, 06:20:39 amHe was employed as a welder.https://www.stuff.co.nz/auckland/local-news/western-leader/106796944/man-who-died-in-west-auckland-explosion-was-a-welder-by-trade

author: KL27x
author_rank: Super Contributor
timestamp: September 06, 2018, 06:59:13 am
content: ^Ahh, yeah. Maybe he only had access to this stuff at work. Hence the jury rig.I imagine a big string of bad luck for him to get that far with no one else noticing and setting him straight, to the point of physically stopping him. Too sad.

author: station240
author_rank: Unknown
timestamp: September 06, 2018, 09:00:24 am
content: AvE is going to have an interesting time if he makes a video on this.

author: KL27x
author_rank: Super Contributor
timestamp: September 06, 2018, 11:44:53 am
content: Ian.M seems to have covered it, already. Simply putting acetylene gas under pressure is waiting for an accident. Mixing pressurized acetylene with oxygen is ensuring more collateral damage.Most people who are interested in getting an oxyacetylene torch for themselves would surely learn the dangers. There is actually an order to turning the gases on and off, even. But people who learned it as a job with someone else handling the equipment puchasing and refilling maybe doesn't care to know the specifics. Or they are just desensitized to the danger. Even with the friend refusing to be near, he shrugged it off. The friend was maybe not that well informed, either, and deferred somewhat to the professional welder.Even if the tank didn't spontaneously ignite due to being dropped or wrenched on, I don't know if a flame arrestor could be trusted to work on the premixed gases.If he wanted to just cut or bend or braze, oxy propane (in separate tanks) would have been relatively safe, I think. But you probably can't get a lot of oxygen in a 300 psi tank. I bet he sneaked the gas from his employer on the sly, without asking; otherwise, he probably would have gotten a more thorough lessen about the dangers.I don't think AvE could do a video on this. The guy died; it makes for a difficult vijayo.

author: amyk
author_rank: Super Contributor
timestamp: September 06, 2018, 11:54:51 am
content: Even the Wikipedia article mentions its instability under pressure, and just search YouTube for acetylene to see how powerful the explosions are... shows that some people, just don't really think.

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 12:20:51 pm
content: Quote from: james_s on September 06, 2018, 04:47:37 amI didn't say ban, I said license. I don't know about where you live but here you need a license to run a petrol station, you need a license to possess explosives, you need a license to install gas fittings and appliances, you need a license to drive and lastly you need a license to compress acetylene or charge cylinders with it. All activities that can be done safely, if you you have the requisite training and knowledge, but which have potentially fatal consequences for other people if you don't have the requisite knowledge and training. I'm all for libertarianism, up to the point where other people's lives are put at risk by 'being able to do whatever you want', at that point a modicum of control and organization is called for. To suggest otherwise is to pursue doctrine in the face and teeth of common sense.

author: rhb
author_rank: Super Contributor
timestamp: September 06, 2018, 12:46:55 pm
content: Where you live you need a license to carry a small pocket knife. Once Britain conquers "knife crime" it will then have an outbreak of "hammer crime".*Any* fuel and oxidizer combination will detonate above a certain pressure. Principle of the diesel engine.

author: KL27x
author_rank: Super Contributor
timestamp: September 06, 2018, 12:52:50 pm
content: QuoteThat wouldn't have stopped this. A petrol station can prevent you from using their pump to fill a garbage bag full of petrol. But once you take your approved container full of gasoline away from their premises, it's out of their control. It sounds like this welder decided to take some gas home with him from work. From his employer, who has to go get his proper certified acetylene tanks filled at a certified dealer. He didn't walk into a store and ask someone to fill his propane tank full of acetyene.

author: CJay
author_rank: Super Contributor
timestamp: September 06, 2018, 12:57:17 pm
content: Quote from: rhb on September 06, 2018, 12:46:55 pmWho's told you that rubbish?Let's quash that particular BS right now though, a link, to a government page:https://www.gov.uk/buying-carrying-knives

author: BradC
author_rank: Super Contributor
timestamp: September 06, 2018, 01:13:52 pm
content: Quote from: rhb on September 06, 2018, 12:46:55 pmNo it's not.A) There is a difference between detonate and deflagrate. Diesels that detonate don't last long. Most fuel/oxidiser reactions are a deflagration. Acetylene is easier than most to coax a detonation. Actually, better to say it takes care to prevent it detonating.B) The ignition source in a diesel is heat. That the heat is caused by *rapid* compression is neither here nor there when comparing it to compressing combustible gasses.C) I can carefully compress a huge number of fuel/oxidiser combinations to the limit of my ability to compress them. As long as I don't impart enough instantaneous energy to ignite them (ie compress them relatively slowly and keep them cool), they won't burn, let alone "detonate". Again, Acetylene can be coaxed to go off all by itself. No oxidiser required. So adding oxygen potentially makes it worse when it does go off.

author: Bud
author_rank: Super Contributor
timestamp: September 06, 2018, 01:15:29 pm
content: Quote from: KL27x on September 06, 2018, 11:44:53 amNot for someone who has no moral in the first place.

author: tggzzz
author_rank: Super Contributor
timestamp: September 06, 2018, 01:57:50 pm
content: In the 6th form I used to go to lectures at the Royal Institution.One of the lectures was detonating stoichiometric mixtures of gasses and oxygen. The last one was, from memory <mumble> years ago, acetylene. It was in a glass milk bottle surrounded by several layers of protection including but not limited to steel cans, armoured glass, and with a wooden lab stool on top of the lot.Detonation was, as expected, a hell of a bang. The lab stool's seat fractured, the armoured glass was no longer effective, and the milk bottle had completely disappeared - and was replaced by a small layer of glassdust.Great fun.

author: taydin
author_rank: Frequent Contributor
timestamp: September 06, 2018, 02:15:14 pm
content: If the only pre-condition for getting a license is completing a course on safely using an oxy-acetylene rig, then I would agree that everybody should get a license before being allowed to acquire oxygen/acetylene bottles.But if that were to happen, I'm pretty sure there will be many extra requirements, like being a member to X, Y, Z associations, satisfying such and such conditions for the workplace, being regustered with Z organization and getting regular safety audits etc. The expense of satisfying these requirements would put oxy acetylene welding way outside of the realm of a hobbyist like myself, who has learned about all safety aspects, and applies them for his oxy acetylene set for years without any incident.

author: CJay
author_rank: Super Contributor
timestamp: September 06, 2018, 02:26:29 pm
content: Quote from: tggzzz on September 06, 2018, 01:57:50 pmAnd there's a very good chance it could be available in their archives if it was filmed

author: taydin
author_rank: Frequent Contributor
timestamp: September 06, 2018, 02:35:43 pm
content: I think what really happened is this:The pressure of the oxygen/acetylene mix in the LPG bottle was too small. As a result, when he ignited the torch, the flame "burned back" into the bottle.This can also happen when oxygen and acetylene are in their respective separate bottles. So first of all, you make sure that the oxygen pressure isn't too low and acetylene cannot flow back into the oxygen bottle from the torch. And secondly, you place flame arresters at the regulators (and to be extra safe, at the torch end as well), so that if the flame started to burn back into the bottles, the flame arresters will seal the bottles.

author: james_s
author_rank: Super Contributor
timestamp: September 06, 2018, 02:41:54 pm
content: Quote from: Cerebus on September 06, 2018, 12:20:51 pmI never said you did mention banning, I said I'm glad I don't have to jump through legal hoops to purchase acetylene. I'm not a dealer selling the stuff, I just have a tank filled now and then. Same as when I buy propane or gasoline or any other flammable material. I have an approved container filled with the stuff and beyond that it's my responsibility. Accidents involving acetylene are rare, so why should someone need a license to purchase acetylene and not need a license to purchase propane or gasoline?Heck, I have natural gas piped right into my home. That stuff is quite explosive under the right conditions too, a few years ago a coffee shop not too far from here was leveled after a gas leak caused an explosion. It has happened to a few houses over the years too, completely flattened them. Anyone could turn on the stove gas without lighting it or fill balloons with it, but common sense says don't do that. Likewise common sense says don't transfer acetylene into improper containers as this guy did.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 02:42:59 pm
content: Quote from: taydin on September 06, 2018, 02:35:43 pmNo, this is a deep misunderstanding of the chemistry and physics of the situation. If the pressure is higher in a combustible mixture then the flame front will burn faster, not slower. What's more, the eventual explosion will be more powerful and more damaging.Please do not experiment with anything like this. Your lack of understanding will cause you harm.

author: taydin
author_rank: Frequent Contributor
timestamp: September 06, 2018, 02:48:50 pm
content: Quote from: IanB on September 06, 2018, 02:42:59 pmWe are not comparing the case where bottle 1 has low pressure oxy/acetylene and bottle 2 has high pressure oxy/acetylene and both blow up. Which one will have a bigger bang. Of course the high pressure one will have a bigger bang.If the oxy/acetylene mix had a high pressure, the flame at the torch would have enough fuel to consume and would not have a chance to burn back. But with low pressure, the flame wants fuel, there isn't enough at the torch tip, so it burns back into the cylinder.When you read the news article, the victim has talked to his friend about how he managed to use one bottle for oxy/acetylene welding. So apparently, when he first filled up the bottle, it had enough pressure in it to prevent back burn. But as the pressure got lower, the likelihood of back burn increased and eventually cost him his life.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: September 06, 2018, 02:49:29 pm
content: Quote from: alpher on September 06, 2018, 02:29:26 amSomebody did, but they don't now.Don't acetylene cylinders have internal magic (solvent/filler) that ensures very little is ever in the gas state?

author: CJay
author_rank: Super Contributor
timestamp: September 06, 2018, 02:56:35 pm
content: Quote from: NivagSwerdna on September 06, 2018, 02:49:29 pmThey have both, acetylene dissolved in acetylene and the bottle is filled with an inert porous material, I assume to stop it sloshing about

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 02:56:39 pm
content: Quote from: Bud on September 06, 2018, 01:15:29 pmQuote from: DictionaryThe moral of this is that one shouldn't impugn someone else's morals (behind their back no less) when you can't even string together a sentence correctly.

author: BradC
author_rank: Super Contributor
timestamp: September 06, 2018, 02:58:30 pm
content: Quote from: james_s on September 06, 2018, 02:41:54 pmI don't want this to come across the way it's going to come across, but common sense isn't that common.I'm routinely astonished at the stupid shit people do because they didn't stop and think, maybe ask a question or do a bit of reading.I'm not voting to legislate Acetylene, but there are some very simply rules that if followed will prevent bad stuff from happening. This ex-muppet violated a number of them. Maybe he never had the dangers and rules explained to him.Being taught the correct order to open and close valves, and how to check the flashback arrestors and torch configuration is a procedural thing. It does absolutely nothing to teach you about some of the actual dangers of the gas should it be used outside of that narrow set of pre-ordained equipment. Maybe he genuinely had absolutely no idea because he'd never come across it, never had it explained and just never though to ask.If you look at it from a point of complete ignorance, acetylene is just like propane. It's a fuel gas, stored in a bottle and used with a regulator. Some people even use their acetylene regulators on propane bottles. Heck they have the same thread! (here anyway). But propane is a crapton safer as a result of having a hugely narrow flammability limit, and an even narrower explosive window, and an even narrower transition into detonation (explosion != detonation). Propane is stupidly much (scientific term there) harder to detonate than Acetylene. Sure it'll burn, but the conditions have to be so tightly defined to get into detonation as to be hardly worth worrying about. Acetylene can detonate if you fart too close to it, especially in a rusty propane bottle, above 15PSI and with copper alloys in contact.The fact it didn't go off before he got to the place he was going to try and use it was a minor miracle in itself.Sad that his daughter no longer has a father, but he may well have never had that "hand on the shoulder" talk about the reason all those procedures and mechanisms are in place, and may well not have had the nouse to ask or read up on it.I'm out in the scrub at the moment working at a high school. They have a well equipped metalwork shop, and 5 welding bays with *massive* signs on the dangers of Acetylene, the procedures for the equipment and what to do if it goes wrong. None of those explain the properties of the gas outside of the equipment.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: September 06, 2018, 03:11:38 pm
content: There is a good video on the basics of oxy-acetylene welding, storing components and especially the pressures involved:As far as i read from the article linked earlier as soon as the oxygen was filled in, it was probably filled in at pressure of its source tank (= 100-200 bar) and no regulator was in place. The pressure alone is enough to get acetylene to combust freely with small amounts of air.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 03:21:31 pm
content: Quote from: taydin on September 06, 2018, 02:48:50 pmNo, no, no, no, no.Your misunderstanding is akin to posters here who do not understand about the relationship between voltage and current, and how Ohm's law works.Your intuition is failing you, and everything you are saying is wrong.

author: Ian.M
author_rank: Super Contributor
timestamp: September 06, 2018, 03:23:19 pm
content: Any competent instructor will emphasise that acetylene can explode ON ITS OWN at the drop of a hat, never to go above 15 PSIG on the acetylene line, and basic safety for acetylene cylinder handling. Either he skipped the safety lecture for a smoko or had forgotten *EVERYTHING* from it except the procedures he did every day in his job.I still say it takes a special kind of stupid to put *any* fuel gas + oxygen under pressure in a cylinder without thinking "This is a bomb!", let alone acetylene + oxygen.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 03:25:57 pm
content: Quote from: BradC on September 06, 2018, 02:58:30 pmHowever, if you filled a cylinder with a pressurized mixture of propane and oxygen, you still would have created a bomb. Mixing any flammable substance with oxygen under confined conditions is a recipe for disaster.

author: mzzj
author_rank: Super Contributor
timestamp: September 06, 2018, 03:34:31 pm
content: Quote from: taydin on September 06, 2018, 02:35:43 pmThis might work with other fuel gases (likesmallhydrogen+oxygen generators used for brazing) but I wouldn't dare to mix oxygen and acetylene in any bigger volume.Acetylene is just waiting for any excuse to explode on your face. Even pure acetylene will explode if you compress it just over 30psi/2Bar. Add oxygen to the mix and it's going to spontaneously ignite if you blink your eye violently.

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 03:34:41 pm
content: Quote from: IanB on September 06, 2018, 03:25:57 pmWhat makes acetylene stand out is that if you fill a cylinder of it at 20 psig, without any oxygen, you have made a bomb. That would not be true with propane, butane, MAPP or even my farts after a killer curry.

author: BradC
author_rank: Super Contributor
timestamp: September 06, 2018, 03:50:20 pm
content: Quote from: IanB on September 06, 2018, 03:25:57 pmI don't think that was ever in dispute.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: September 06, 2018, 04:20:51 pm
content: Quote from: CJay on September 06, 2018, 02:56:35 pmIn acetone, no?

author: bd139
author_rank: Super Contributor
timestamp: September 06, 2018, 04:29:42 pm
content: What a muppet.I use to play with carbide crystals when I was a kid. As a little vandal, I used to put them in the dog crap bins, pour in some water, wait a bit and fire a roman candle at it. This taught me that acetylene was not to be fucked with. On one occasion it blew the metal support clear out of the ground. When you see the people doing it with barrels, imagine the end was closed. And that wasn't even pressurised!

author: tooki
author_rank: Super Contributor
timestamp: September 06, 2018, 04:30:32 pm
content: Quote from: CJay on September 06, 2018, 12:57:17 pmHeh, yyyyeah… Americans have lots and lots of crazy misconceptions about the Old World, both positive and negative.(I'm an American living in Europe. I have had to explain to people in USA that no, I don't pay 60% income taxes. No, preservatives and food coloring and other additives aren't actually categorically banned here. No, there aren't death panels deciding who gets healthcare. No, there aren't cows hanging out on my street in the city. No, not everyone in Europe is fancy and erudite, every place has its own equivalents to white trash and hood rats. No, there actually is McDonald's here, and it's popular. And yes, they DO have cheddar cheese in England. Funny, that…And no, not everyone in Switzerland is filthy rich!)

author: Sparky49
author_rank: Regular Contributor
timestamp: September 06, 2018, 05:07:27 pm
content: Pocket knife license.I hope you realise you'd need a license to ask if someone has their pocket knife license? Or is that starting to become too outlandish to believe?

author: SparkyFX
author_rank: Frequent Contributor
timestamp: September 06, 2018, 05:13:49 pm
content: Btw LPG (Liquefied Petroleum Gas) tanks are usually thin sheet metal, designed for propane/butane mixes not unlike whats in a lighter.Not to be confused with CNG (compressed natural gas) pressure bottles, that are designed for 300 bar.It should make people stop and think if you intend to fill something from a thick walled bottle into a much less stable container that this might be a bad idea...

author: taydin
author_rank: Frequent Contributor
timestamp: September 06, 2018, 05:23:26 pm
content: Quote from: IanB on September 06, 2018, 03:21:31 pmYea, that's a convincing argument right thereThat's my clue to stop the discussion with somebody.

author: CJay
author_rank: Super Contributor
timestamp: September 06, 2018, 05:30:42 pm
content: Quote from: alsetalokin4017 on September 06, 2018, 04:20:51 pmUgh, typo, yes, acetone, my bad.

author: bob225
author_rank: Frequent Contributor
timestamp: September 06, 2018, 05:35:20 pm
content: As someone who has argon 7L (for welding) and a divers bottle(s) I have a respect for the bottles and storage even being inert gases there still a bomb/rocket if not handled correctly, 300psi can do a lot of damageIts sad that he died leaving behind his daughter, a little or no knowledge is a dangerous thing

author: station240
author_rank: Unknown
timestamp: September 06, 2018, 05:40:53 pm
content: Quote from: IanB on September 06, 2018, 03:25:57 pmYou don't actually need to mix propane with oxygen to make the cylinder explode. Search for the term "propane bleve"Boiling Liquid Expanding Vapor Explosion (BLEVE) is often the result of a fire burning around the cylinder/tank that causes the liquid inside to boil.Effectively like a steam explosion from over pressurized gas.There are whole towns that no longer exist after BLEVE incidents, not just propane or LPG either.

author: CJay
author_rank: Super Contributor
timestamp: September 06, 2018, 05:49:16 pm
content: Quote from: tooki on September 06, 2018, 04:30:32 pmNooo, we can get Cheddar here in England? All this time I've been smuggling Cheddar in from Belgium and nobody told me?Seriously though, some of the stories I've been told by Americans about my own country, I don't know if I should laugh or cry, one of my favourites came from my partner who used to work in a London hotel, a sweet American couple wanted to know if she could book them a taxi to Edinburgh so they could have afternoon tea at the castle and be back for their dinner that evening.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 06:02:46 pm
content: Quote from: taydin on September 06, 2018, 05:23:26 pmYes, I'm sorry about that, but what else can I say? To let you know that you are wrong can be done briefly. To educate you into a better understanding may take a long time. It may even take a complete education in chemistry, physics, fluid flow, and combustion engineering.Some insight may be gained from looking at few of Cody's recent YouTube videos on combustion in a vacuum chamber (Cody's Lab). He found (somewhat surprisingly) that gunpowder will not burn in a vacuum, even though it does not need an external source of oxygen. In combustion, pressure is very important. At high pressure things burn fast. At low pressure things burn slowly or not at all.

author: langwadt
author_rank: Super Contributor
timestamp: September 06, 2018, 06:18:39 pm
content: Quote from: IanB on September 06, 2018, 06:02:46 pmI think idea here is that at some low pressure in the bottle the flow out of the bottle is slower than the flame front sothe flame travels up the hose and into the bottle at which point the burning inside the bottle increases the pressureand eventually it explodes

author: taydin
author_rank: Frequent Contributor
timestamp: September 06, 2018, 06:29:58 pm
content: Quote from: langwadt on September 06, 2018, 06:18:39 pmExactly. And that's why flashback arrestors are put on the hoses, so that if the flame travels back the hose, into the cylinder, the flashback arrestor closes and prevents a disaster.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 06:32:59 pm
content: Quote from: langwadt on September 06, 2018, 06:18:39 pmYes, but that is about flow velocity and not pressure. Also, when you have a fuel/oxygen mixture the speed of a moving flame front can be much faster than the flow velocity in a tube. That's why a normal gas torch mixes fuel and oxygen right at the tip. There is also the situation that the flow is controlled by some kind of lever at the torch end to control the flame size. For a given flame size the flow velocity in the tube is slower when the pressure is higher because for a given mass flow the product of velocity and density is constant.True that when the velocity slows close to zero the possibility of flash back is much higher, but I predict the explosion would happen long before then.The really crucial thing is that you never, ever mix oxygen and a flammable material in a confined space. Ever.

author: chris_leyson
author_rank: Super Contributor
timestamp: September 06, 2018, 06:40:04 pm
content: I had no idea acetylene was so volatile, didn't teach me that in school metalwork classes. My only attemp at oxy-acetylene welding was a disaster, mostly unsupervised and I used a cutter to 'weld' some coffee table legs together, well that explained why the steel disapearedSome time later I made a small steam engine, it would never have worked, too much slop in the mechanics. Anyway building a steam boiler was considered to be " a little dangerous" and with no available compressed air supply the other sources of compressed gas were oxygen or acetylene, oxygen was considered to be less than safe because of the graphite covered string used as piston seals so acetylene it was then.Quite unremarkable really, the mechanics didn't budge because of the poor machining and the place stunk of acetylene. Looking back I sometimes thinkyou couldn't do that nowadays.

author: coppercone2
author_rank: Super Contributor
timestamp: September 06, 2018, 07:28:06 pm
content: if the man did this and is a welder I am convinced he was extremely intoxicated

author: tooki
author_rank: Super Contributor
timestamp: September 06, 2018, 07:42:50 pm
content: Quote from: CJay on September 06, 2018, 05:49:16 pmHah, fantastic!Many a Swiss I've talked out of their plan to visit USA for 2 weeks, intending to rent a camper (caravan) and drive around literally half of mainland USA… they're like "well LA and Las Vegas are right next to each other, right? Like maybe a half hour or so?" (It's more like 4-5h in good traffic.)They're still vastly outnumbered by the sheer masses of Americans who don't know that Switzerland and Sweden are different things. I couldn't begin to tell you how many times I've been asked "Oh!! You lived in Switzerland?? How's your Swedish?!" My usual reply is that since I've never been to Sweden, I only know what I learned from the Ikea catalog…

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 08:06:53 pm
content: Quote from: tooki on September 06, 2018, 07:42:50 pmIt's lucky that Swaziland changed its name this year then... "Mom, I went to get the money out of the Swiss bank and it'sreallyhot here, there's this weird black and white striped horse wandering down the street, there's a heck of a lot of black folks here, even more than in Baltimore, and that Swedish language course I took is useless, nobody understands a word I say!"

author: edy
author_rank: Super Contributor
timestamp: September 06, 2018, 09:01:20 pm
content: I remember using oxy-acetylene torch back in high school, I guess I would have been 14 or 15 years old? I welded together an anchor out of bits of pipe and covered it with brass solder. It was awesome! Thick black powdery smoke before the oxygen was turned on.... it would get in my nose. I remember blowing my nose and finding black soot in there.Anyways, when it came to turning it off... our shop teacher always said "A" before "O" or UP YOU GO! I will never forget that line.I've never fully understand why, and I see there are different opinions, something to do with "flashback" and "pop". Maybe someone can explain. But yes.... we had the opportunity to oxy-acetylene at a very young age and without incidence, despite it being a school with kids running around of various intelligence levels.... kind of surprising now that I look back at it.

author: bd139
author_rank: Super Contributor
timestamp: September 06, 2018, 09:07:43 pm
content: Quote from: edy on September 06, 2018, 09:01:20 pmThe acetylene goes bang pretty nicely just with the relatively low oxygen concentration in air thus it's more important to turn that off first or it can build up. Acetylene is very slightly lighter than air so it tends to head up to the roof of a building and will quite happily build up and then sudden ignition takes place. Ka-boom.Money shot at 4:03 but worth watching the whole thing.

author: tooki
author_rank: Super Contributor
timestamp: September 06, 2018, 09:09:24 pm
content: Quote from: Cerebus on September 06, 2018, 08:06:53 pmIndeed!What is hilarious to me is the spelling of the new name, which itself is a legitimate word in their language, but looks like a turn-of-the-millennium dot-com-bubble web startup!As for language courses, something that really trips up nearly all immigrants here is that the local language (Swiss German) is sufficiently different from standard German as to render their German classes useless. They arrive here, confident that they've learned enough to get by (and indeed in Germany it would be), and instead encounter a language that is incomprehensible, and which is hard to learn because everyone will instantly switch to standard German or English for you.P.S. How'd you remember that I used to live in Baltimore?(Fuuuuuck do I miss Maryland crabs, and awesome Korean food, and good sushi, and Royal Farms chicken…)

author: bd139
author_rank: Super Contributor
timestamp: September 06, 2018, 09:16:36 pm
content: Indeed. All I know to say is: Wo ist die biberfladen und apfelkuchen! (and that's probably wrong)

author: M4trix
author_rank: Frequent Contributor
timestamp: September 06, 2018, 10:06:26 pm
content: Polish oxygen-acetylene recoilless cannon.https://youtu.be/kLwvWgaixpI

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2018, 10:10:01 pm
content: Quote from: tooki on September 06, 2018, 09:09:24 pmA friend of mine at University was an Army Brat, and as a young child lived in Germany and quite naturally became quite a fluent speaker of Hochdeutsch. Her father was an Army lawyer, and this entailed quite a lot of extended trips to Switzerland. She says, as a small child, she could never understand why the Swiss couldn't talk properly. Clearly it left an impression because, as an adult, she used to say "Schweizerdeutsch!" as if she was simultaneously spitting and naming the most reviled politician you can think of.QuoteI didn't, I don't think I did anyway. I just named the blackest US city that I knew of.

author: tkamiya
author_rank: Super Contributor
timestamp: September 06, 2018, 11:17:22 pm
content: I think we can all sit back and criticize this particular situation. But many of us, at some point, have done stupid things, and scared ourselves beyond bathroom break as we learned more.I am a licensed electrician (my license is from Japan and I was formally trained), and I'm often amazed how home owners casually do things that are quite dangerous. Some people are just oblivious. On hobby front, for me, is a high voltage. Luckily, the shock I received was strong enough to give me quite a scare but not enough to kill me. It's easy to overplay your hands when you don't know any better. Often times, it's more important to know what NOT to do, rather than what to do. A good idea may have a good reason why it's not done that way.....

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2018, 11:32:07 pm
content: Yes. I good working assumption is that everything you see being done a certain way is most likely done that way for a reason.Similarly, every part you find in a product or installation was also put there for a reason.

author: amyk
author_rank: Super Contributor
timestamp: September 07, 2018, 02:27:06 am
content: Quote from: bob225 on September 06, 2018, 05:35:20 pmEspecially now with the Internet you can safely look at all sorts of stuff from the comfort of your own home, including cylinders turning into rockets and various explosions of different gases.Lots of videos of acetylene explosions too, but unfortunately I couldn't find one where it's not being explicitly ignited.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 07, 2018, 02:36:45 am
content: I think the Mythbusters would have some fun trying to replicate the results. That should help answer the question of how explosive acetylene is under pressure.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 02:59:17 am
content: Quote from: bd139 on September 06, 2018, 04:29:42 pmDid you live in a mining town?When I was a kid, my Uncle & Grandfather had a smallish Gold mine in Wiluna, West Oz.They always used "carbide lamps" when they went underground, & I still remember the harsh light & distinctive smell of them.My Dad was brought up in a mining area, & in his day, the kids were bloody little rogues.One of their "pranks" was putting carbide & water in an old fashioned lemonade bottle which had a glass marble inside which sealed the bottle neck.The marble would seal the rising gas pressure up to a point, giving the kids time to clear the area prior to it going bang in a big way.They got into trouble for rolling one of these under the school when the teacher was having a refreshing nip of brandy during break time!It's a wonder that didn't kill themselves or end up in prison!

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 04:33:32 am
content: Quote from: CJay on September 06, 2018, 05:49:16 pmIt sort of works the other way round, too.Many years ago along with a couple of other "Boys from Oz", I hired a car on Southampton, UK.We proceeded in normal Australian style to put 300 miles "on the clock" over the weekend.When we returned it, the manager refused to believe the speedo reading & wrote it down as a faulty uniton the log.

author: Monkeh
author_rank: Super Contributor
timestamp: September 07, 2018, 04:39:15 am
content: Quote from: vk6zgo on September 07, 2018, 04:33:32 amShe mustn't get around, 300 miles in a day is nothing but a moderate trip even in the UK.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 05:53:06 am
content: Quote from: Monkeh on September 07, 2018, 04:39:15 amHewas adamant!Of course, this was back in the 1970s--- people probably get around by car a lot more now.In those days, they seemed to just keep their car "as a pet", only taking it out on weekends.Most travel was by public transport, with long trips usually train or coach.People would take a Sunday drive from SOTON to Bournemouth, get stuck in an almost endless traffic jamfrom about halfway through the New Forest, see about 5 minutes of their destination, & get stuck into the same thing on the return trip.I asked, "Why don't you go to London, it'll take about the same time by the Motorway on Sunday?"The dour answer was usually:- "London's very overrated".

author: bd139
author_rank: Super Contributor
timestamp: September 07, 2018, 06:05:02 am
content: Quote from: vk6zgo on September 07, 2018, 02:59:17 amNot a mining town. A friend’s father was into collecting mining lamps and we nicked his carbide stash. Also found the local outdoors store (army and navy surplus) at the time stocked it for cavers. Could buy a cool Kg of it for £2.I would have probably hung out with your dad

author: tooki
author_rank: Super Contributor
timestamp: September 07, 2018, 09:10:45 am
content: Quote from: bd139 on September 06, 2018, 09:16:36 pmOr in (Zurich dialect) Swiss German: Biberli und Öpfelchüechli!Quote from: Cerebus on September 06, 2018, 10:10:01 pmHeheheh I believe it! I think that to Germans, Swiss German is looked upon as something rather provincial, like the Appalachian dialect of English is in USA!Quote from: Cerebus on September 06, 2018, 10:10:01 pmAnd you'd be close: of major cities, only Detroit has a higher % of black residents (and appreciably higher, at that!). Balto is a great city though. I love that it's a place that celebrates its dirty underbelly, rather than pretending it doesn't exist, like other places do. It has a certain whimsical, don't-take-yourself-too-seriously nature that most places don't have. (Washington DC, which Balto lives in the shadow of, takes itself more than seriously enough forbothcities…)

author: bd139
author_rank: Super Contributor
timestamp: September 07, 2018, 09:20:32 am
content: Quote from: tooki on September 07, 2018, 09:10:45 amSee I failed already

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 10:47:56 am
content: Quote from: bd139 on September 07, 2018, 06:05:02 amOnly if you are a centenarian!I was telling that story to a young EE who was originally from Vietnam, & he topped it with the way him & his mates used to find unused munitions from the Vietnam War (usually rifle & machine gun cartridges), get them open, & use the guts to make very potent fireworks.Amazingly, none of the silly buggers managed to kill themselves!Back to topic.Thousands of home handy persons owned oxy-acetylene equipment over decades, with a vanishingly small percentage coming to grief.When I first got an "oxy set", I was a complete "oxy moron" for about a year, finding hundreds of jobs for it, then my use of the gear diminished, till I found I was paying a not inconsiderable rental fee for bottles which I wasn't using, so I sent them back, & packed up the gauges torches & hoses.They are still there,in good condition, & I've been tempted to get some "non-rental" bottles & do some jobs around the house.As with most such things, I go & have a "lie down" till the feeling goes away!

author: Psi
author_rank: Super Contributor
timestamp: September 07, 2018, 12:07:20 pm
content: Quote from: bd139 on September 06, 2018, 04:29:42 pmSame, growing up we had a welding plant that used carbide and water instead of a acetylene gas tank.To keep it feed we had a large plastic drum of carbide in the garage for over 20 years. And this was in a residential city neighborhoodI think we only ever used 1/2 the drum in the 20+years before we sold the whole thing.I once detonated a few granules of carbide in a 2L coke bottle with some water and spark igniter. It made a dry ice bomb look like a Christmas cracker/bon bonI shudder to think what size explosion could have been achieved had the entire drum been converted and detonated at once.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 07, 2018, 01:03:50 pm
content: Quote from: IanB on September 06, 2018, 06:32:59 pmUh, no. A normal oxy welding torch mixes the gasses right after the valves in the handle. Yes, the mix present in the channel from there to the tip IS explosive. If you sequence the lighting right the flame does not burn back into the torch because the velocity of flame propagation is slower than the gas velocity in the fine hole at the tip. Only as the gas expands and slows down on emerging can the flame front keep up with the flow. If you turn the gas flow up too high, you can blow the flame away from the tip.Of course if you turn the valves down too far, you get a nice POP as the gas mix in the torch detonates. And if you reeeely fuck up, you can blow up the hoses. (Never done that myself.) I don't even want to think about what it would take to get a mixed gas back into either of the cylinders.Part of the art of oxy welding is adjusting the gas rate and proportion to achieve the desired state of oxidizing or reducing chemistry at the flame tip. Recognizable from the visual characteristics of the flame.The oxy cutting tip has a ring of fine jets carrying oxy-acet mix gas. These small flames are used to heat the target steel to red heat. Then the central pure oxygen jet is turned on. The hot steel catches fire in the oxygen, and that is a VERY exothermic reaction. It's the burning steel that melts itself. The oxygen jet is forceful enough to blow the resulting iron oxide slag out of the way.Heh. Someday I'd like to try using a thermal lance. Those things rock.QuoteIt seems you've never used an oxy torch. If you're in Sydney some time, drop me a line and you can have a go.QuoteExcept:1. When you want to blow something up. Like unwanted ants nests. Woohoo!2. In the end of an ordinary oxy torch. It's a small space and the metal is thick enough to take the bang if you mess up.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: September 07, 2018, 01:15:26 pm
content: Quote from: coppercone2 on September 06, 2018, 07:28:06 pmNot only that... it might also be worth noting that burn gases and inert gases use different threads on the fittings, so you can not accidentially connect them the wrong way or at all.Acetylene bottles/pressure regulators and maybe the torches have a left hand thread (the nut is marked with indents), oxygen or argon/co2 have right hand threads.That almost requires intentional wrongdoing, either while connecting all components, during filling or during use.An oxy acetylene rig always requires flashback arrestors, just because at some point the bottles will be empty and pressure and flow rates will not be stable in the system.

author: Stray Electron
author_rank: Super Contributor
timestamp: September 07, 2018, 03:09:51 pm
content: Quote from: Cerebus on September 06, 2018, 08:06:53 pmFunniest post of the day!

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 03:31:37 pm
content: Quote from: SparkyFX on September 07, 2018, 01:15:26 pmIt is only in relatively recent years that flashback arresters have been available.In the previous eighty to ninety or so years, people got along without them, with the accident rate still being miniscule.I'm not deriding them, we should have them, but it isn't quite as black & white as "always".When the bottles become almost empty, it is evident, because it is not possible to maintain a stable flame.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: September 07, 2018, 04:13:47 pm
content: Quote from: vk6zgo on September 07, 2018, 03:31:37 pmIt was teached some 22 years ago in welding classes i attended to have them in place - because they are a good idea for protection. Maybe we aren´t talking about the same thing. The devices i talk about pose an increase in cross sectional area, held separate by two paper-like diaphragms. Should back-pressure or a flame come backwards, this will make the diaphragm close the supply. They are ridiculously cheap, i even got some in my kid-size oxy torch "rig".The other remarkable protection was to not lower the temperature required for an ignition by improperly lubricating oxygen supply fittings (oils and grease and such).

author: Cerebus
author_rank: Super Contributor
timestamp: September 07, 2018, 04:27:16 pm
content: Quote from: vk6zgo on September 07, 2018, 03:31:37 pmI knew you were old mate, but I didn't realise that you weresoold that the nineteenth century was "relatively recent years" from your perspective.Nineteenth century examples of dry and wet types of flashback arrestors, for use with oxy-hydrogen.:

author: HighVoltage
author_rank: Super Contributor
timestamp: September 07, 2018, 04:39:08 pm
content: In our town in my childhood, a "smart" plumber wanted to show his coworkers, how oxygen and acetylene can make a nice little explosion.He filled an air balloon with a perfect mixture until it almost popped.Then he ignited the balloon with a cigarette lighter.He went to the hospital with bad burns in his face and him and all his co workers had popped eardrums.Because of his stupidity, the German government closed his business.Some people are just plain stupid!

author: mzzj
author_rank: Super Contributor
timestamp: September 07, 2018, 04:43:46 pm
content: Quote from: TerraHertz on September 07, 2018, 01:03:50 pmAnd oxy-hydrogen torches use pre-mix even in the hose (and some smallish volume inside the electrolysis chambers and scrubbers)Low volume, low pressure and "explosion" safe design being the key points there..(btw: oxy-acetylene mix has about 4 times higher energy density than oxy-hydrogen)

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 04:58:32 pm
content: Quote from: SparkyFX on September 07, 2018, 04:13:47 pmThe things I am referring to screw onto the gauge or handset instead of the hose, then the hose screws on to that, rather like an inline attenuator with "N" connectors.Normally they use them at both ends of each hose.

author: taydin
author_rank: Frequent Contributor
timestamp: September 07, 2018, 05:09:36 pm
content: I like the turn of the century design where the gases go through a water tankThat seems like an ultra reliable way of stopping a flame going back to the cylinder.The design that I'm using at the moment has steel wool inside of it and a drop of solder. A flame supposedly causes the solder to melt and set a spring free, which then goes and closes the end.Comparing these two designs, I find the water method to be much more reliable.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2018, 05:19:58 pm
content: Quote from: Cerebus on September 07, 2018, 04:27:16 pmNote that the examples you show are for oxy/hydrogen not oxy/acetylene.This is what modern ones look like:-https://www.weldclass.com.au/blog/16-flashback-arrestors-your-questions-answeredThe Australian Standard referred to in the linked article only dates from around 1984, so I was correct in saying "relatively recent years"They were certainly not supplied with the oxy set I bought in the late 1980s to replace an earlier one that was stolen, so were not mandatory then.

author: Cerebus
author_rank: Super Contributor
timestamp: September 07, 2018, 07:28:41 pm
content: Quote from: vk6zgo on September 07, 2018, 05:19:58 pmYeah but you said "relatively recent years ... available", not "mandatory". More than a century, given the Industrial Revolution's around 200 odd years old, is only going to be "relatively recent" to someone with a very long lifetime. Admit it, you're the Count de Saint Germain and slipped up, thereby outing yourself.

author: jmelson
author_rank: Super Contributor
timestamp: September 07, 2018, 10:23:48 pm
content: Quote from: alpher on September 06, 2018, 02:29:26 amDo you have a typo, there?Commercial acetylene tanks hold acetylene dissolved in acetone, and that is stored in fuller's earth. The pressure in the bottles is relatively low.Jon

author: m3vuv
author_rank: Super Contributor
timestamp: September 08, 2018, 12:35:33 am
content: years ago i was messing about with oxy accetalyne,i lit the welding torch adjusted it for a neutral flame then stubbed the torch out leaving the gas comming out of the nozzle,i got a bin bag and held it over the nozzle untill it was inflated,i used masking tape to seal it and took it to the bottom of the garden,luckily i lived out in the sticks at the time and didnt have neibours,i put the bag at the bottom of the garden about 50yds from the house and workshop,i used a piece of masking tape for a fuze lit it and stood just in front of the workshop,after about 5 seconds there was what i can only describe as an explosion,i felt the shockwave (nearly knocked me over),i heard a noise from the workshop,went in and found a load of tins of paint etc had came off a shelf on the gable end,the shock must of rattled the garage wall,it was block built as well,the bin liner wasnt either fully inflated,if he had a proper ratio mix under pressure,im supprised there was anything left of him!!,i think if i remember as an explosive its not far behind c4 scarey stuff!!!.

author: amyk
author_rank: Super Contributor
timestamp: September 08, 2018, 12:50:55 am
content: Quote from: vk6zgo on September 07, 2018, 05:19:58 pmPage 20 ofthis century old bookshows the same water-chamber type for acetylene.

author: duak
author_rank: Super Contributor
timestamp: September 08, 2018, 02:49:18 am
content: I was, I think fourteen years old when I got a lead-acid motorcycle battery. It had a nifty 6 mm diameter plastic tube to vent hydrogen released during charging. I cranked up the charger from 6 V to 12 V to get some real electrolysis happening. I figured I'd get a nice little flame when I lit the hydrogen coming out of the tube.Guess what happened next?There was a good POP, part of the side of the battery was shot across the room and the battery moved the other way about 20 cm or so. Acid was sprayed across the counter fortunately away from me.My sister has alway said that if we didn't have bad luck we'd have no luck at all. I'd disagree in this case, it was bad news for the battery but I could have got acid or debris in my eyes. I'll take that as good luck.Cheers,

author: alpher
author_rank: Frequent Contributor
timestamp: September 11, 2018, 12:44:12 am
content: Quote from: jmelson on September 07, 2018, 10:23:48 pmI don't see any typos there, do you?

author: amyk
author_rank: Super Contributor
timestamp: September 11, 2018, 02:02:37 am
content: Quote from: duak on September 08, 2018, 02:49:18 amNow consider that hydrogen is actually rather mild in terms of explosive force, compared to acetylene or even propane...Hydrogen:Propane:Acetylene:

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 11, 2018, 02:44:09 am
content: Wasn't that last one the only one premixed with pure oxygen?

author: duak
author_rank: Super Contributor
timestamp: September 11, 2018, 03:59:58 am
content: I took my sons out to a day at the chem lab at one of the local universities where they did the balloon demos. Hydrogen and hydrogen with air were pretty good - you didn't need hearing protection but it was a good idea. Hydrogen and oxygen definitely needed hearing protection - it was a good thump in the chest.Has anyone been to Top Fuel drag races where they use nitromethane as fuel for the cars? Although I knew they would be LOUD, the first time I saw them I was surprised by the visceral thumping. Rock concerts could very well be louder, but the impact is indescribable. It almost seemed like the air became much more dense; like a liquid.Gummi Bears in liquid oxygen burn almost as brightly as thermite. I remember seeing a video by (I think) George Goble who got a charcoal brazier (Hibachi) ready in about two seconds flat by pouring a cup of liquid oxygen on the briquets. Actually, almost all of the cast iron Hibachi burned leaving just the feet.

author: drussell
author_rank: Super Contributor
timestamp: September 11, 2018, 09:17:25 am
content: Quote from: vk6zgo on September 07, 2018, 03:31:37 pmI don't think that is quite true. I remember seeing ones on the hoses of some very old rigs when I was a kid. Plus, that 1916 book linked to earlier talks about early styles of torches that needed flame arresters, how they were constructed chambers with asbestos cloth layers interleaved with wire mesh, etc.

author: tautech
author_rank: Super Contributor
timestamp: September 11, 2018, 10:02:38 am
content: Quote from: m3vuv on September 08, 2018, 12:35:33 amThe muggins that blew himself up lived ~15 mins drive away.Yeah oxy sets are great tools and fun.....if you're bloody careful.I got my first at 13 going 1/2 share with pop and had it for 40+ years before losing the lot in a shed fire.None of the bottles exploded but melted the fusible plugs on the taps and vented safely as their supposed to do.Unlike some bigger bottles in a local workshop fire when I was a kid that popped and took a leg from each of two fireman fighting the blaze. The remains of those jagged exploded bottles are set as a monument to their efforts outside the Kumeu/Huapai volunteer fire station to this day.Any compressed gas need be treated with respect !Copied from a post I did a few years ago when not wanting to offer too much info in case some twit blows themselves up:QuoteSadly their mum and one of the sons are no longer with us and both gone from natural causes.

author: tautech
author_rank: Super Contributor
timestamp: September 11, 2018, 10:25:06 am
content: About things that go boom, couple of interesting vids in this thread:https://www.eevblog.com/forum/beginners/will-this-work-fireworks-detonator/

author: bd139
author_rank: Super Contributor
timestamp: September 11, 2018, 10:46:05 am
content: Cool stuff. My school "technology project" at A level was abomberr fireworks detonator. Still got it somewhere. Looked like a cheesy 1980s film prop.

author: mtdoc
author_rank: Super Contributor
timestamp: September 11, 2018, 11:59:32 am
content: On acetylene filled balloons: In high school we used to get the guy down the street with an acetylene tank in his garage to fill up a baloon for us. We’d put it in a brown papet bag and bring it to school. Then at lunch time, we’d light the bag on fire and throw the whole thing in a large metal garbage can out on the quad. BOOM! Good times.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 11, 2018, 01:34:13 pm
content: Quote from: Cerebus on September 07, 2018, 07:28:41 pm"Mandatory" was by way of an afterthought, to point out that even after the issuing of a Standard in1984, regulations had not caught up by around 1987 or so.The "water" type of arrestor may well have been used in places with a gas manifold feeding many welding sets, but it was not viable for portable units.The "portable" ones in that old patent don't look like they would be effective, so they may not have been taken up.Maybe they were used elsewhere, but they were not used in Australia with portable equipment.Unfortunately, I didn't spend any of my time when overseas "perving"on welding shops.The modern units are considerably more complex & seem to be very effective, but they are expensive.If I had to buy them & the gas, it would cost more than a cheap electric welder, so I am thinking again about getting my "oxy set" going again.

author: Urs42
author_rank: Unknown
timestamp: September 11, 2018, 03:05:04 pm
content: Some exploding acetylene cylinders:

author: Bud
author_rank: Super Contributor
timestamp: September 11, 2018, 03:05:35 pm
content: Quote from: mtdoc on September 11, 2018, 11:59:32 amBaby talk! Real boys threw chunks of sodium extracted from stems of engine exhaust valves in toilet bowlsA rapidly moving fire ball on the water followed by a Boom and a splash of water.

author: james_s
author_rank: Super Contributor
timestamp: September 11, 2018, 03:23:09 pm
content: Quote from: mtdoc on September 11, 2018, 11:59:32 amI was just telling somebody the other day how I'm glad I went to school when I did rather than now, because so many of the things that were just fun back then would get someone expelled and/or arrested these days.I still remember my friend in elementary school making a fake movie style bomb out of clay and batteries and wires and a calculator and had it out on the playground. The teacher found it and lectured him for wasting school supplies, that was it. I shudder to think what would happen now.

author: grythumn
author_rank: Contributor
timestamp: September 12, 2018, 03:16:27 pm
content: Quote from: IanB on September 06, 2018, 06:02:46 pmThe Mythbusters successfully fired a revolver in a vacuum chamber, but I believe it was with a modern "smokeless" propellant.https://mythresults.com/bullet-baloneyI wonder if Cody'd have more luck if the gunpowder was in a cartridge fired by a primer charge... it'd have a chance for the gas pressure to build and allow the combustion to continue.-R C

author: Bud
author_rank: Super Contributor
timestamp: September 12, 2018, 03:23:17 pm
content: That is begging a question if common explosives would detonate in vacuum

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: September 12, 2018, 05:20:08 pm
content: Not sure if it's been mentioned but the proper acetylene cylinders have a stabiliser filling in them, usually a kind of wool or similar. Apparently just storing liquid acetylene in bulk on its own risks an explosion. Thus, using the wrong type of cylinder is a hazard even without the oxy.Also, it should never be allowed to come into contact with copper or silver as it forms an unstable compound with it.Though if he was a chavmobile exhaust fitter, that calls for a posthumous public service recognition award.For the propane bottle.

author: jmelson
author_rank: Super Contributor
timestamp: September 12, 2018, 07:24:54 pm
content: Quote from: IanMacdonald on September 12, 2018, 05:20:08 pmAcetylene is NOT in liquid form in any cylinder. I'm not a chemist, but I'm thinking that the conditions needed to liquefy it would almost certainly cause an exothermic decomposition reaction. But, under the wrong circumstances, this can happen anyway. These can be astonishingly violent, with one bottle wrecking an entire neighborhood. We had one in our area some decades ago.Acetylene is dissolved in liquid ACETONE, which is stabilized by a solid filling material, which is usually Fuller's earth.QuoteYes, that can form copper or silver acetylide. Not so horribly dangerous in small quantities, but it can trigger an acetylene decomposition.Jon

author: TerraHertz
author_rank: Super Contributor
timestamp: September 13, 2018, 01:35:04 am
content: Quote from: Urs42 on September 11, 2018, 03:05:04 pmGreat fun to watch, but those are all just cylinder bursts due to heat, followed by BLEVEs of the contents. (Boiling liquid expanding vapor explosion.) Not a single high VOD shock wave in sight. Luckily for everyone nearby.

author: Beamin
author_rank: Super Contributor
timestamp: September 13, 2018, 08:37:40 am
content: How could you be so stupid to think "hey lets combine the two I can't believe no one thought of that before!" seriously I don't think this guy was all there.I put a oxidizing flame into a rubber glove and filled it up about 5". We lit it from about 15' and felt the concussion and never did that again, car alarms went off and the fire department stopped by. That was from maybe 3 or 4 seconds of gas from the torch head, but a pressurized bottle of it? That's insane. Louder then an m80 or a 12 ga shot gun easily.I knew a guy that got drunk and was too stupid to figure out how to light the torch in the adjacent apartment building basement. When I stopped by the next morning I saw the gauges at zero. First thing I did was check the valves and both were wide open. Luckily I used almost all the gas the day before. He left the bottles open and passed out. If that was 1/10th full the place would have blown up three apartment buildings. Unfortunately any idiot can play with these torches. Just cranking the acetylene up and lighting it is scary loud and violent and that's with no oxygen. Just pressurizing the gas above 15 PSI and it can blow up with no oxygen or spark. You should have to pass a test or a class to own/rent one. I had mine chained to a wall with a lock so no one could knock them over.Why didn't he assume the flame wouldn't go back into the hose? I know everyone thinks this at first even with LP and air torches.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 13, 2018, 03:30:18 pm
content: Quote from: Beamin on September 13, 2018, 08:37:40 amIn the US, to buy refrigerant requires an EPA certification (heard that's not really required for HFCs but most supply stores insist on it anyways) when the biggest danger is that it can displace oxygen just like any other compressed gas can do. But flammable gases are generally not regulated and anyone can buy them.

author: langwadt
author_rank: Super Contributor
timestamp: September 13, 2018, 04:49:43 pm
content: Quote from: NiHaoMike on September 13, 2018, 03:30:18 pmmany places require certification to buy or work with refrigerant, yet many freeze sprays and signal horns use r134a as propellant ..

author: taydin
author_rank: Frequent Contributor
timestamp: September 13, 2018, 04:58:11 pm
content: Acetylene cylinders do have a safety mechanism that kicks in when the acetylene in the cylinder starts to burn. Once burning starts, at a certain pressure, the bottom of the cylinder will pop open. So instead of the cylinder exploding, it will start spraying fire out of its bottom and move around with the thrust created, which is still a hazard, but preferrable over a cylinder explosion.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 14, 2018, 08:12:09 am
content: Quote from: blueskull on September 13, 2018, 03:42:22 pmYour comment is a welcome injection of common sense into a series of postings which are rapidly degenerating into the first cousin to the"Eeek!! You're going to work on tube equipment!!Or :-"You are going to look at the Mains without a differential probe?" Aaaeeeiiiii!!threads!You can come to grief if you are very inexperienced, coupled within inability or disinclination to find out how to do things correctly, or are just plain stupid, but most of these things, if you apply even half the attention needed to drive a car, are much safer than that everyday activity, & have been done by millions of people for decades with a miniscule number of accidents

author: Cerebus
author_rank: Super Contributor
timestamp: September 14, 2018, 04:49:00 pm
content: Quote from: vk6zgo on September 14, 2018, 08:12:09 amYou seem to fail to grasp the quintessential difference between:"Eeek!! You're going to work on something where you could kill yourself!!and"Eeek!! You're going to work on something where you could kill everybody in a 50m radius!!Most of us are quite happy for idiots to have the freedom to do the first, preferably below breeding age, but are quite reasonably concerned that sensible precautions ought to be put in place to make the latter more difficult for unqualified idiots to do. Asking for operators of potentially explosive equipment to have some form of certification or licensing is no more extreme than saying drivers ought to pass a test and hold a licence. For your position to be consistent you would also have to advocate for theremovalof licensing restrictions on drivers and apart from the odd knuckle dragging Ayn Rand reader (comic book form, obviously) you'd have a hard time finding people who'd agree with that proposition.

author: Beamin
author_rank: Super Contributor
timestamp: September 15, 2018, 10:39:40 pm
content: Quote from: NiHaoMike on September 13, 2018, 03:30:18 pm

author: Beamin
author_rank: Super Contributor
timestamp: September 15, 2018, 10:42:44 pm
content: Quote from: NiHaoMike on September 13, 2018, 03:30:18 pmI used to buy r134a in those 4 or 5 gallon green tanks just buy ordering it all the time. They even said I could order r12 for over $1200 a bottle. Had oxy acetylene too with no hassle. Plus they sell little bottles of 134a at the auto parts store to anyone.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 16, 2018, 02:50:29 am
content: Speaking of qualifications I hear they still let people post, who seem unable to grasp the concept of editing obvious typos and deleting accidental empty double posts.But then, I suppose double posting doesn't kill anyone. Fortunately for us, or we'd all be dead by now wouldn't we Beamin?

author: vk6zgo
author_rank: Super Contributor
timestamp: September 18, 2018, 09:30:34 am
content: Quote from: Cerebus on September 14, 2018, 04:49:00 pmThe hyperbole is strong in this one!(1)"You could kill everyone in a 50m radius."That is quite a large area, 7853.9816 sqm by my HP22sMy house sits on an 805 sqm block, so I could fit 9.75 such blocks, complete with houses in that area.Since most DIY people don't weld in the middle of an open area of that size, occupied by a lot of people, we have to allow for the real world, in which most people other than the dumbo who stuffs up, are protected by the brick walls of their homes, so most of the damage (& injuries) will be confined to the immediate (small) area around the gas bottle explosion .In a large factory, such an area could be possible, but even then, there are likely to be some obstructions, & most importantly, the operator in that case should have been trained correctly in the use of the equipment.(2) Somehow, because I pointed out that the reaction here was extreme, you extrapolated that to imply that I am a devotee of Ayn Rand, which I most emphatically am not!When I had a swimming pool, I could go into the pool shop & buy a 7 litre bucket sized container of chlorine, without any licence to use it, or any verbal warning about letting oil come into contact with it.The warningwasshown on the container, & in the literature you could pick up at the pool shop.Reports of people blowing up their sheds from misuse of that product are much more common than mishaps with oxy-actelyne equipment.Gas welding equipment commonly includes a small, but "fat" book on the use of the device, including all the safety warnings.Most novices, far from being foolhardy, are positively "timid" when first using an oxy set, because they have heard all the scary stories.One story, (probably apocryphal) going the rounds when I was a kid, was of somebody using an arc welder absent-mindedly striking an arc on an "unused" acetylene bottle.All the above said, a licence to use oxy-acetylene equipment would be a good idea, if it also incorporateda short training course, & was reasonably inexpensive.If it was costly, & meant to block the DIY user from the use of such gear, I would oppose it.

author: Cerebus
author_rank: Super Contributor
timestamp: September 18, 2018, 05:05:04 pm
content: Quote from: vk6zgo on September 18, 2018, 09:30:34 amStandard practice for British fire brigades when dealing with acetylene cylinders that might cook off is to apply a 200m exclusion zone (Official Guidance Document). I'm going to bow to people with actual operational experience of dealing with the hazards from exploding acetylene cylinders. Given that, I thought I was being conservative suggesting a figure of 50m for a potentially lethal zone.Anyway, here in Blighty there are plenty of back street garages and the like within spitting distance of domestic premises. The high street garage I use has domestic dwellings on three sides of it and a busy road in front. It doesn't really matter whether the lethal radius is 5m, 10m, 20m or 50m. What matters is the principle that something with the capability to be lethal to innocent bystanders if mishandled ought to require some proof of competence before you're allowed to store and use it in quantities that pose a significant hazard to the general public.Also you seem to have undue faith in the protective qualities of brick walls. Brick walls are not a good thing to hide behind if you're in the vicinity of a significant explosion or shrapnel from one.As you seem to like calculations the heat of combustion of acetylene is 50.2 MJ/kg. Commercial acetylene cylinders available in the UK hold between 1.13m3and 9.01m3of acetylene at STP. That's between 50 and 402 moles - one mole of acetylene is 26.04g. That's between 1.3kg and 10.47kg of gas. That's between 65.26 MJ and 525.6 MJ. The oft quoted "TNT equivalent" is 4.184MJ/kg. So the smallest common commercial cylinder of acetylene has a TNT equivalent of 15.6 kg of TNT and the largest 125.6 kg.AnM-67hand grenade contains 180g of explosive (Composition B, a mix of TNT and RDX), has a lethal radius of 5m, injury radius of 15m and fragments can be thrown to 250m.TheM795155mm high explosive artillery round contains 10.8kg of TNT. I can find no figures on its quoted lethality, but it's a safe bet that one does not want to be home (in a brick built house) when one is dropped on one's neighbour.So the smallest commonly commercially available (in the UK) cylinder packs more explosive potential than the commonest high explosive artillery round. Even if these figures were off by an order of magnitude (they are not), that ought to drive home to anybody the potential level of deadliness of improperly used or stored acetylene cylinders.Quote from: vk6zgo on September 18, 2018, 09:30:34 amNo you inferred, I did not imply. Go back and read it again.Quote from: Cerebus on September 14, 2018, 04:49:00 pmI duly note that, although you could have used the same basis to dispute "knuckle dragging" (which again was not implied of yourself) you did not, and thus must be assumed, by inference, to have embraced it.Quote from: vk6zgo on September 18, 2018, 09:30:34 amSo you, via a twisty and turny route, finally find yourself having to agree that mandatory proof of competence by way of licensing for operators and keepers of acetylene is reasonable and sensible. Above you characterise "the reaction here was extreme", yet you find yourself having to take the position that you're characterising that way in the same comment. My very first comment in this thread included:Quote from: Cerebus on September 06, 2018, 01:28:46 amHardly a call for a draconian regulatory regime, and I don't recall anyone else in this thread asking for a 7 year welding apprenticeship or anything similarly onerous as a prerequisite for a putative license.

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2018, 12:07:45 am
content: QuoteI'm sure the average house has more energy than that just in the 2x4's for the frame. If you could accidentally make a proper bottle explode, that would be different. Even the entire trailer truck of bottles cooking off (posted earlier in the thread) wouldn't have blown up a residential neighborhood or anything like that.Licenses for this are stupid. If someone has intent to harm other people, paying $30.00 to take a 5 hr nap while some retired hill billy reads a 10 page brochure isn't going to deter them. Show me where terrorists used acetylene gas to kill people. Show me where criminals have held up a business or a bank with a bottle of acetylene. Show me where an accident killed the neighbors on either side.Like fertilizer, there's a matter of quantity. For larger quantities sure. To fill a bottle, it's not a big deal unless there's some consequence to society. I don't see evidence of it.

author: helius
author_rank: Super Contributor
timestamp: September 19, 2018, 12:15:59 am
content: At a swapmeet yesterday, I saw a pocket-sized "torch" with piercer-type slots for 12g oxygen and butane canisters. I'm sure that could get exciting in case of a leak.

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2018, 12:24:49 am
content: The reason that drivers licenses work is because they identify people. The test is just so the government can say "we told ya." The actual implementation/importance is in the motor vehicle registration and identification/accountability. Almost anyone that isn't legally blind can get a driver's license. It's after they fuck up that they lose it. The test doesn't screen out alcoholics or testosterone laden idiots.The guy in the OP would have been accountable for any damage or injury he caused whether or not he had some stupid license. When people start doing damage and getting away with it, that's when we need registration of people buying acetylene. This Harold guy knew what he was doing was dangerous, because his friend told him to stop and refused to be in the vicinity, if nothing else. He took his chances. As long as "Harolds" are few and far between, requiring licensing for personal use would be a bigger problem.

author: Cerebus
author_rank: Super Contributor
timestamp: September 19, 2018, 12:59:47 am
content: Quote from: KL27x on September 19, 2018, 12:07:45 amSo something explosive has to be in active use as weaponry by terrorists and criminals before you consider itproperlydangerous? AndIget accused of hyperbole? Why do you bring intent into it? It's not deliberate mayhem that we're trying to avoid but people who are terminally stupid, or think they "know best" - you know like the guy on the building site who doesn't wear a hard hat, or use a harness when working at height because "I've done this for twenty years and I'm still hereeeeeeeeeeeeee" <Splat!>.Quote from: KL27x on September 19, 2018, 12:07:45 amUse Google, the list of fatal accidents involving acetylene as a primary cause is very long.Here's a van, well what's left of it, whose driver died because of an acetylene leakHere's the green building in the background:

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2018, 01:08:41 am
content: QuoteEither that OR it causes significant damage to other people.If a guy very rarely blows up his van or his shed or his entire house, it's unfortunate.Just google suicide rate and compare that to how many people die from acetylene accidents and tell me why it matters.And you think spending tax payer money for a bunch of cunts to come up with a formal accreditation course will fix that? You think the guy in the van knew his tank was leaking but didn't know it could explode? No, it was an accident, and he didn't know the valve got bumped.It takes a paragraph to describe what not to do. IanM pretty much covered it. I wonder what else they can do in a licensing class that will mean squat other than bore people to death.And tell me, what percent of applicants do you suppose are going to fail this course/test? If you said anything but zero, you're kidding yourself. Accidents happen in real life; it's not because people are too dumb to pick the right answer on a common sense multiple choice quiz while someone is watching.It's like you think needing a license to buy rope, or some education about how people squish when they fall from 100 feet, is going to stop people from falling off mountains.When the guy in the van's family successfully sues the distributor of the acetylene... this is when you will need a frigging license and registration to buy acetylene. It will be to protect the seller, not you.

author: Cerebus
author_rank: Super Contributor
timestamp: September 19, 2018, 01:31:40 am
content: Quote from: KL27x on September 19, 2018, 01:08:41 amAh, so you have an acceptable body count in mind below which it's unacceptable to spend a cent of public money, do you? Not that anybody mentioned spending any public money, it's quite easy to make these things self-financing. How many bodies exactly? How many deaths/100,000/annum is your threshold for a cause of fatalities to be worth trying to do something about?

author: vk6zgo
author_rank: Super Contributor
timestamp: September 19, 2018, 01:37:31 am
content: Quote from: Cerebus on September 19, 2018, 12:59:47 amDamage to large areas of glass? -----yesDamage to wooden? window frames?----yesDamage to brick walls?-----nothing visible in the pix.Surely, using your examples, there would be huge holes in them.Was there any injury to anybody else? ---well, you don't tell us, so we can only guess.

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2018, 01:37:56 am
content: QuoteShow me one accident that would have been stopped by licensing. Harold? No. He could have swiped it from his employer. Even if the employer took a useless day course and paid his $25.00, it wouldn't have mattered.Your thing with the hard hat or harness? Guess who cares about that? Their employers are the ones on their ass about that. And it's not because they give a shit about the guy on the scaffold. It's because they care about OSHA fines, workmen's comp, or the guy's widow and her lawyers. Do you think the guy on the scaffold doesn't know what happens if he falls? Do you think he needs more education about gravity? If you work for yourself, you can build your own 100 foot high private tower without any safety gear, if you want, and no one will bother you about wearing a harness or a hard hat, or using non-OSHA compliant tools.If you can convince your employer you won't sue, you might be allowed to work 1000 feet in the air with no harness. The Navajo Indians were allowed to build skyscrapers with no harness, because their employers trusted their familes to not sue.

author: Cerebus
author_rank: Super Contributor
timestamp: September 19, 2018, 01:55:13 am
content: Quote from: KL27x on September 19, 2018, 01:37:56 amAs they say up north "There's no talking to some people".

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2018, 02:11:50 am
content: QuoteWhat's the point of posting this? We were talking just fine. If you change your opinion, it's ok. If you still believe in it, then you have a long way to go to support your argument, and we are all ears. It's an interesting point of view, you have.In the US, there are very few people who buy acetylene outside of a professional work environment. Many professional welders do not even bother to have acetylene at home. Not wanting to die is a pretty good deterrent to anyone who won't use it on a regular basis. A lot of places in the US, private monopoly is making it too expensive, anyway. You have to lease the cylinders by month, whether you use any gas or not. Besides, we have plasma cutters and TIG/MIG. I wonder if there are more people jumping out of airplanes (and sometimes dying) or private acetylene rig owners, here.When Kim Kardashian tweets something about oxyacetylene being great fun for all, then we might need some regulation. Fucktards aren't generally interested in cutting and welding things and paying a several hundreds of dollars for the privilege. And I guarantee the guy selling the gas at the welding shop scrutinizes unrecognized faces asking for a fill, and he makes sure their gear is well-maintained. (Both because he is aware of the dangers and he doesn't want to blow himself up, and also because he has new gear to sell you).Before you cry for tighter regulation, ask yourself if you had a single thought about this topic before this forum thread. And ask yourself if you will care in 6 months from now.

author: Cerebus
author_rank: Super Contributor
timestamp: September 19, 2018, 02:28:20 am
content: Quote from: vk6zgo on September 19, 2018, 01:37:31 amI wasn't trying to prove a particular thesis, and I don't see why you're seeking to imply that. It was, as stated, aleakin a van not a whole cylinder exploding ab initio. The report, coming from the Telegraph and a local northern newspaper documenting an explosion in Wolsingham, Durham is remarkably remiss in failing to specifying the exact quantity of gas involved in the explosion. I can't imagine why they were so remiss on the physics unless they were distracted by the trivial issue of a man dying as a consequence of a preventable explosion in a public place.I picked it simply because it was the first I could find that had pictures of surrounding as well as the erased body of a vehicle. I though that perhaps the obvious realities of the sight of a fatal explosion might drive the real-world consequences home to those quibbling about the supposed futility of licensing and the huge restriction in people's freedoms that they imagined that might entail. The pictures came fromhttps://www.thenorthernecho.co.uk/news/3787789.Acetylene_gas_explosion_____Hundreds_could_have_died___/andhttps://www.telegraph.co.uk/news/uknews/1552777/Welder-dies-in-van-blast.htmlWere there other injuries? No other fatalities listed, but why does it matter? That there aren't is mere happenstance concerning who was near or not when it happened at 7am. Would you volunteer to be standing between the van and the buildings behind? Isn't the danger self evident enough without being able to supply you graphs of the overpressure in various locations compared to the quantity of a high explosive necessary to achieve the same overpressures.

author: Beamin
author_rank: Super Contributor
timestamp: September 23, 2018, 04:25:10 pm
content: Quote from: TerraHertz on September 16, 2018, 02:50:29 amThank you for pointing out the fact that I'm legally blind and losing more and more of my eye sight. Some days it looks like I'm looking through wax paper. You think it's annoying to read a post with typos try dealing with this all day every day knowing there is no cure and it's only getting worse. Then add to that people who get impatient that it takes you longer to do things because they can't be inconvenienced for 30 seconds. It takes me a long time to make a post and sometimes errors go through even after I check them like when auto correct changes things and it looks the same to me. Rather then just give up I do it anyways and just try to ignore the people that are unpleasant and considerate. I didn't chose this nor would I wish this upon anyone else. Sick of being called lazy when I have to put in double the effort to make something 1/2 as good.