propane freeze spray - Page 1
Forum section: electronics / general

author: jheissjr
author_rank: Contributor
timestamp: July 01, 2025, 02:10:16 am
content: I made an adapter to turn a propane cylinder into freeze spray. I underestimated how much oil comes out in standard use with the propane. The oil is added in the cylinder to give it the smell. The oil is burned with the propane in regular use and doesn’t matter. For freeze spray, it’s not burned off and the PCB looks like it’s sprayed in oil with a hose. Any ideas for other freeze sprays?https://www.amazon.com/dp/B0DHQGNLTL?ref=ppx_yo2ov_dt_b_fed_asin_titlehttps://www.amazon.com/DozyAnt-Universal-Propane-Throwaway-Disposable/dp/B019CND6J2

author: antenna
author_rank: Frequent Contributor
timestamp: July 01, 2025, 03:08:28 am
content: Butane made for lighters (not pen torches) often has no odorous sulfur compounds.I'm waiting to see the non-flammable suggestions myself

author: amyk
author_rank: Super Contributor
timestamp: July 01, 2025, 03:22:18 am
content: Propane is just about the worst gas you could use for a freeze spray because of its extreme flammability. R152a, R134a, or R143a as commonly found in "gas dusters" would be far better.

author: Someone
author_rank: Super Contributor
timestamp: July 01, 2025, 04:13:36 am
content: Quote from: amyk on July 01, 2025, 03:22:18 amWhy bother with Hydrofluorocarbons ? CO2 is dirt cheap and just needs some sensible ventilation relative to the volume used.

author: jheissjr
author_rank: Contributor
timestamp: July 01, 2025, 04:44:26 am
content: QuoteWhat do you suggest for a spray paint can size dispenser?

author: Mr.B
author_rank: Unknown
timestamp: July 01, 2025, 04:56:08 am
content: A sodastream cylinder, suitable adaptor and PPE.

author: iMo
author_rank: Super Contributor
timestamp: July 01, 2025, 05:08:55 am
content: Once upon a time on an electronics flee-market a guy showed me a freeze spray intended for "killing the insects". I thought it is a scam so we talked about it and the guy offered to me to show how it works. He sprayed me with it in my hand's palm. Unbelievable pain, I would not do it again. He talked about -40C.

author: BradC
author_rank: Super Contributor
timestamp: July 01, 2025, 05:12:48 am
content: I use Butane frequently.

author: Brumby
author_rank: Unknown
timestamp: July 01, 2025, 05:30:22 am
content: Quote from: jheissjr on July 01, 2025, 02:10:16 amI got this far and cringed, for this same reason:Quote from: amyk on July 01, 2025, 03:22:18 amI had one experience with a small amount of butane escaping during the refuelling of a butane powered torch/soldering iron that ignited (No, the iron was NOT running during the refuelling, for those who might be wondering.). The flame was elegant and while it only lasted 3 to 4 seconds, it seemed an eternity as I saw it drift higher and higher. Until that flame extinguished, I was seriously anxious ... and you want to deliberately spray highly flammable gas into the air. My suggestion is: don't!Go for a readily available solution. Just search for "freeze spray". I found such products under the brands CRC, Protech, Servisol and Chemtronics in 2 seconds with Google. There are bound to be more.While I do not deny the evaporation of volatile gases will produce the desired result, I am ever wary of what could happen if things go wrong.

author: RoGeorge
author_rank: Super Contributor
timestamp: July 01, 2025, 07:52:33 am
content: The cold comes from the sudden release of pressure, so why not using compressed air instead of propane?Many compressors come with an air tank, and with filters to remove air humidity. Or buy CO2 cylinders, if for some reason it is not possible to have an air compressor.

author: BradC
author_rank: Super Contributor
timestamp: July 01, 2025, 07:59:10 am
content: Quote from: RoGeorge on July 01, 2025, 07:52:33 amNo, the cold comes from the latent heat of evaporation of the liquid in the can. That is a *significant* difference.Grab a can of freezer spray. Now hold it upside down and spray the gas on your palm. Turn it right side up and spray the liquid on your palm. Which one causes frostbite?

author: tggzzz
author_rank: Super Contributor
timestamp: July 01, 2025, 08:32:16 am
content: Quote from: iMo on July 01, 2025, 05:08:55 amI have, occasionally, used a standard electronics freezer spray to remove warts and verrucas.That mechanism is very controllable. Yes, you could get it to hurt and possibly damage yourself, but that would require determination and stupidity.EDIT: I wouldneverapply that so someone else, since I cannot whether I'm cooling their skin too much.

author: Ranayna
author_rank: Super Contributor
timestamp: July 01, 2025, 09:13:08 am
content: Quote from: tggzzz on July 01, 2025, 08:32:16 amNow i wonder whats in the cans that are sometimes standing on the table at my dermatologist.These are cold by themselves, there is visible condensation on them.

author: tggzzz
author_rank: Super Contributor
timestamp: July 01, 2025, 09:19:35 am
content: Quote from: Ranayna on July 01, 2025, 09:13:08 amI have seen a doctor put acetone into a container, blast cold gas (CO2 from a pressurised ampoule) through it so it forms a slush, and then put the slush on the wart. The acetone and CO2 ampoule can be stored easily for long periods in a cupboard - very practical for occasional impromptu field use.The physics of a slush would ensure the temperature is in a narrow range. When put on the skin, the skin temperature will be defined by the amount of heat in the slush, which is determined by the heat capacity and mass. Overall the result is that the wart would be cooled down by to a temperature that is better limited than by the uncontrolled application of a freezer spray.Having felt the desirable temperature once, it isn't difficult to replicate it with the freezer spray. I would never use freezer spray on someone else.

author: BradC
author_rank: Super Contributor
timestamp: July 01, 2025, 10:23:16 am
content: Quote from: Ranayna on July 01, 2025, 09:13:08 amMy dermatologist uses liquid nitrogen. She has this neat little integrated spray bottle thing and a large dewar out the back to fill it up from.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 01, 2025, 10:43:28 am
content: @RoGeorgeIt's not only release from pressure. Heat of vaporization plays a factor when very low boiling liquids are used.@? dermatologistsA lot use liquid nitrogen, which can be applied by sprayers or on swabs.1,2-dichloroethane was used years ago in dermatology and for local freezing. I don't know if it still is used. I use 1,1-difluoroethane, which is common in dusters that are not just compressed air. I use a bitterant free version called "Gust." Its availability probably varies by state. It is also flammable.CO2 from compressed cylinders (like used to power airguns, Crosman brand) can be used, but that is probably more expensive. Larger CO2 cylinders as used in the beverage industry are far less expensive but bulky. My "man lift" uses them.Finding something that is non-flammable, cold enough, not too cold, can be easily stored for long periods, doesn't contain non-volatile additives, and doesn't cause cancer if you live in California is difficult. CO2 meets many of those requirements.

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: July 01, 2025, 11:49:29 am
content: Quote from: Someone on July 01, 2025, 04:13:36 amI think you would need a regulator. CO2 tanks are ~800 PSI, propane tanks are ~150 PSI.

author: Gregg
author_rank: Super Contributor
timestamp: July 02, 2025, 06:40:06 pm
content: A vortex air cooler system would certainly be safer than propane or any other flammable refrigerant cold spray. Using propane in lieu of freeze spray is just plain stupid.One major drawback to propane is that it is heavier than air and tends to accumulate in lower levels; hence it is not recommended for use onboard boats.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 02, 2025, 06:53:23 pm
content: Quote from: ifonlyeverything on July 01, 2025, 11:49:29 amHow is that a serious impediment for those worried about destroying the world or getting cancer (if you live in California)? I suspect they cost insignificantly more on Amazon" than a propane tank at Home Depot.*About $22

author: thm_w
author_rank: Super Contributor
timestamp: July 02, 2025, 09:11:56 pm
content: Some boiling points for comparison:- Butane -1°C- 1,1-difluoroethane -25°C- Propane -42°C- Carbon dioxide -78°C- Nitrous oxide -88°C- Liquid nitrogen -196°CFor non-flammable stuff CO2 is probably the cheapest, N2O is also quite cheap with the recent abuse craze.

author: Circlotron
author_rank: Super Contributor
timestamp: July 02, 2025, 11:04:23 pm
content: Nitrous oxide seems to be readily available and non toxic in small doses.

author: Someone
author_rank: Super Contributor
timestamp: July 02, 2025, 11:24:30 pm
content: Quote from: Circlotron on July 02, 2025, 11:04:23 pmLow Toxicity =/ Low Danger.Nitrogen and most hydrofluorocarbons simply dilute air. But N2O and CO2 disrupt oxygenation of the blood and present immediate life threatening dangers at much lower concentrations, with N2O being signficantly worse.

author: langwadt
author_rank: Super Contributor
timestamp: July 02, 2025, 11:59:24 pm
content: Quote from: Someone on July 02, 2025, 11:24:30 pm"inert" gasses are worst because when you need to breathing basically runs on CO2 level not O2 level, so if there is no O2 there is no CO2 in the lungs and you won't even know that you are suffocating

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2025, 12:07:01 am
content: Quote from: langwadt on July 02, 2025, 11:59:24 pmWhile it is true CO2 stimulates breathing, the converse is not true. That's one reason nitrogen asphyxiation for capital punishment is effective and presumably painless. You just keep breathing regardless of the CO2 concentration and don't notice its absence.Edit: Most of the CO2 in your lungs and blood comes from you , not the atmosphere.

author: langwadt
author_rank: Super Contributor
timestamp: July 03, 2025, 12:10:51 am
content: Quote from: jpanhalt on July 03, 2025, 12:07:01 amyeh so you don't feel suffocating you just pass out

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2025, 12:12:17 am
content: You don't even know you "pass out." It's a myth that says you do.PS: You type a lot faster that me. Note my edit.

author: thm_w
author_rank: Super Contributor
timestamp: July 03, 2025, 12:21:04 am
content: Quote from: Someone on July 02, 2025, 11:24:30 pmCO2 above about 3% is dangerous (though anything over about 0.1% is not optimal for health), nitrous is given to patients at levels up to 9%. So I don't think that your concern is relevant unless you are working in a small sealed room. We are talking about using a few grams to freeze an IC.Greenhouse wise N2O is apparently 300 times worse than CO2 though.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2025, 12:48:50 am
content: You don't get to 3% in typical situations easily. As for danger, there are plenty of warning symptoms. In a lab I worked, we has a walk-in incubator (35°C) with 3% to 5% CO2. You could work in there for short periods without adverse effects.

author: Someone
author_rank: Super Contributor
timestamp: July 03, 2025, 01:13:13 am
content: Quote from: thm_w on July 03, 2025, 12:21:04 amDelivered in controlled situation with trained medical person monitoring (to produce an intended sedation effect) is not the same as unintentional exposure! Not comparable at all.3% and higher concentrations are obtained even in ventilated rooms, I tried to evacuate a room at 5% but the acclimatised workers just shrugged and carried on. 5% N2O would have had much higher effects on them.

author: amyk
author_rank: Super Contributor
timestamp: July 03, 2025, 02:34:42 am
content: Incidentally, the propellant used in aerosol cans and meant to be used relatively casually, like hairspray and air fresheners (odourisers), when marketed as "natural", really means "flammable hydrocarbon" - often a propane/isobutane mix:https://s3-ap-southeast-2.amazonaws.com/wc-prod-pim/Asset_Documents/Air%20Wick%20Aerosol%20Pure%20Spring%20Delight%20SDS.pdfQuote from: jpanhalt on July 01, 2025, 10:43:28 amNote that many small CO2 cylinders are just compressed gas; to get an actual freezing effect, you need liquid CO2.Also, the refrigerants used in common freeze sprays go down to around -40, but CO2 is much colder.

author: Analog Kid
author_rank: Super Contributor
timestamp: July 03, 2025, 02:41:28 am
content: I thought breathing excess nitrogen results in the bends.

author: Mr.B
author_rank: Unknown
timestamp: July 03, 2025, 02:44:11 am
content: No, that is dissolved nitrogen in the blood expanding and forming bubbles as pressure decreases, typically during a dive ascent that is too rapid.Breathing air too rich with nitrogen simply asphyxiates.Edit to correct some wording.

author: Circlotron
author_rank: Super Contributor
timestamp: July 03, 2025, 07:50:12 am
content: Yep, okay, ignore my suggestion regarding nitrous oxide. In my neighbourhood there seems to be an epidemic of N2O sniffing, In the last several months I have found twelve empty 3kg cylinders of the stuff lying in parks and on the roadside. And no dead bodies, at least not yet. The stuff is marketed as whipped cream propellant.https://www.miamimagic.com.au/cdn/shop/files/MiamiMagicInfusions_3.3LPinkCylinder_USA_1.jpg?v=1706865685&width=1100

author: coppercone2
author_rank: Super Contributor
timestamp: July 03, 2025, 08:10:14 am
content: You don't want to use N2O. I found the most cold is when something evaporates. The freon will douse the thing being cooled and rapidly evaporate off of it. CO2 can do similar, if it condenses dry ice on the object. N2O will not do this. And likely you just found some post concert/party debris. essentially hippy liquor bottles.N2O is used when you need it to dissolve in certain things (i.e. high solubility in lipids), or to make a variation of a oxy/fuel flame (less hot) for some temperature work (soldering, brazing (particularly on aluminum).if you mix dry ice with a solvent you get a special case, it is a slurry that maintains a somewhat constant low temperature. Different alcohols and solvents reach different temperatures. This is useful for condensing gases for chemistry experiments or drying vacuum pumps.If you shoot a RTD with the freeze spray you will see that it gets ridiculously cold, I believe I got something like -60 C on a rather large RTD.I feel that chemtronix freeze spray is a very formidable product in terms of cooling small objects to temperatures that are very low. Keep in mind it gets very impractical to use it on electronics when it gets this cold, when its this cold, the dew point is very low, meaning you get frost even when its very dry. I have shorted out op-amps before during experiments, they got damaged from the ice that built up on the part.For spot cooling, a double RTD (commercial) will get a insulated object to around -50C after a while if its cooled well.Frost is always your biggest problem here.What I would like to know is what people found they can do with these low temperatures. I managed to put together some stuff that can achieve these low temperatures and I am sadly out of ideas. As far as reaching a milestone goes, this one is kinda bleak, applications wise.The main thing to keep in mind with cooling:the amount of energy aphase changewill remove per gram will over totally over shadow a PV=nRT change in temperature, even if the change in pressure is vast. Liquid evaporating = phase change. Gas decompressing is PV=nRT. Its weak in comparison to phase change. Ice melting is334 J/gram. To increase the temperature of 1g water by 1C is only4J. 334/4 = 84.A factor of 84 is HUGE.The exact calculation has to do with latent heat. Also keep in mind about N2O, Like I said, its like oxygen-lite for fire. Good enough to make a real "nasa" rocket with or to improve the performance of a cutting torch over using air. So any design using it has special fire concerns. If you know about O2 related fires, you know its not even close to a joke...

author: BradC
author_rank: Super Contributor
timestamp: July 03, 2025, 08:29:46 am
content: Quote from: coppercone2 on July 03, 2025, 08:10:14 amN2O is stored in the bottle as a liquid, so it certainly does evaporate when sprayed.

author: coppercone2
author_rank: Super Contributor
timestamp: July 03, 2025, 08:31:22 am
content: Maybe some huge ass medical or distribution bottle. Not the ones in the media panicthat might be in the shady black balloon filler van in a concert parking lot that sounds (and shakes) like there is a titanoboa inside, probably eight 6 foot tall tanks on a manifold that make the thing bounce on the suspension.

author: BradC
author_rank: Super Contributor
timestamp: July 03, 2025, 08:46:21 am
content: Quote from: coppercone2 on July 03, 2025, 08:31:22 amYes the ones in the media panic. FFS stop shooting from the hip and do some basic research.Medical N2O is known as Entonox and is a 50/50 gaseous mix between N2O and O2. Cream chargers are *liquid*.

author: coppercone2
author_rank: Super Contributor
timestamp: July 03, 2025, 08:51:41 am
content: thats a 15lb tank the size of a fire extinguisher lolUsually people litter 12gramcartridges.I also wanna see the genius idea for getting liquid out of that thing you linked, for this cooling application, that makes this remotely practical in a way that is actually reliable / usefulany trick that works for propane has about a extra 750 psi problem for all the hardwareI wonder what that low grade china stainless does when it starts getting cold at 900 psi when someone tries to take liquid out of it

author: BradC
author_rank: Super Contributor
timestamp: July 03, 2025, 09:11:37 am
content: Quote from: coppercone2 on July 03, 2025, 08:51:41 amAny they have 12 grams of liquid. Not gonna argue, so I'm out.

author: NE666
author_rank: Frequent Contributor
timestamp: July 03, 2025, 09:25:20 am
content: Whilst there's some interesting discussions here, I seriously fail to see the point in taking ANY of the risks being highlighted, nor undertaking any of the complexity involved, rather than just using a readily available, commercial freezer spray can.If you were doing it on an industrial scale, maybe. But for hobby use, I don't see it.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2025, 09:44:10 am
content: Quote from: Analog Kid on July 03, 2025, 02:41:28 amI am not a diver, but my understanding is that "bends" and "rapture of the deep" (aka nitrogen narcosis) are both due to nitrogen. Both are related to the high solubility of nitrogen. The first is bubble formation as already described. The second is probably due to disruption of nerve conduction, just as one sees with many anesthetics, such as cyclopropane.. It does not require particularly high pressure, just a high partial pressure of nitrogen.There are now 4 states that allow nitrogen asphyxiation for capital punishment according to Google. Alabama was the first to actually use it. I had no part in choosing nitrogen over any other gas, such as argon or helium, but suspect that the narcotic effect may have been a factor in its selection. It also costs less.

author: tooki
author_rank: Super Contributor
timestamp: July 03, 2025, 09:56:46 am
content: Quote from: jpanhalt on July 03, 2025, 09:44:10 amYep.Apparently,allbreathable gases except helium (“and probably neon”, according to wiki) exhibit narcotic effects at high pressure. So for deeper diving, divers use gas mixes with helium, so that despite the gas high pressure, the actual amount of other gases is kept low enough to be safe.Because those so-called “technical gases” (in diving lingo) are conversely unsafe to use at shallower depths, deep dives require changing gas mixes at various depths. In some long, deep cave dives, they do multiple preparation dives to strategically deposit cylinders of gas at different depths.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2025, 10:15:40 am
content: @tookiThe narcotic effects of nitrogen v. (say) argon are said to be related to its high solubility infatsand interruption of neural junctions. Solubility in water is a different story. It does not require a particularly high pressure of nitrogen to see that effect.

author: tooki
author_rank: Super Contributor
timestamp: July 03, 2025, 10:33:43 am
content: Quote from: Analog Kid on July 03, 2025, 02:41:28 amNot exactly.I don’t know how much you know about diving. But basically, you are breathing compressed air*, and the regulator constantly adjusts the pressure so that it is equal to the pressure imposed by the water column above you, so that it’s in equilibrium. (Otherwise your lungs would collapse due to the water pressure squeezing the heck out of you.) This means that the deeper you go, the higher the mass of air you have in your lungs, even though the volume stays the same. This much higher air pressure facilitates nitrogen dissolving into the blood, so your blood (and then the water in other body fluids and tissues) gets more and more nitrogen dissolved into it, until eventually reaching saturation**.If you then decompress too quickly (by ascending too fast), the dissolved nitrogen can outgas as bubbles, just like opening a bottle of soda. Those bubbles, in turn, can cause harm. (The term “the bends” comes from bubbles forming in joints, IIRC.) So with the exception of the saturation diving described in the footnote, divers must plan “decompression stops” during the ascent, where you just dwell at certain depths for a little while to allow safe elimination of nitrogen.The amount of nitrogen dissolved in the blood is a function of depth x time. So even fairly shallow dives can require significant decompression stops, if the dive time was very long. (For recreational scuba divers, the dive time is typically limited by the air cylinder, so decompression stops are minimal. But it becomes a real issue if using rebreathers or air supplied by hoses from the surface, either of which enable much longer dives.)In other words, you need to unscrew the cap from the soda bottle veeerry carefully and slowly to let the gas escape slowly.*up until you reach depths where nitrogen narcosis becomes an issue and you have to switch to special gas mixes containing helium. This is where it becomes “technical diving”, usually the purview of professional divers, as comparatively few recreational divers bother seeking the necessary training and certifications.**Once saturated, decompression can take a full week, so professional divers who need to do things like underwater welding do “saturation diving” where they stay saturated for extended periods, like weeks, and live in a compressed habitat on the support boat in between dives, followed by a single decompression. Otherwise they’d spend far more time decompressing than working…

author: tooki
author_rank: Super Contributor
timestamp: July 03, 2025, 10:38:11 am
content: Quote from: jpanhalt on July 03, 2025, 10:15:40 amThe narcotic effect is known to affect all breathing gases except helium (“and possibly neon”). The effect is simply known to bestrongerin gases with high lipid solubility, like nitrogen.

author: thm_w
author_rank: Super Contributor
timestamp: July 03, 2025, 11:19:50 pm
content: Quote from: amyk on July 03, 2025, 02:34:42 amAny sodastream or small 12g/16g cartridge you buy will be liquid, as explained above about nitrous. 12g liquid CO2 expands to ~6L of gas. Example:https://www.amazon.com/Guard-Dog-Security-CO2-Cartridges/dp/B0C13XDFHTQuoteyes, that is why I posted a list of temperatures above.Quote from: NE666 on July 03, 2025, 09:25:20 amSure but thats our thing, taking things to extremes.A can of non-flammable MG super cold 134a 400g is $30-40. 400g sodastream refill is about $20. As you say not much reason to bother when you might go through a can every few years.

author: tooki
author_rank: Super Contributor
timestamp: July 04, 2025, 08:23:50 am
content: Quote from: iMo on July 03, 2025, 10:49:39 amOnly if you’re soldering and/or farting into your air supply at 100 feet or more under the sea!

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 09:17:38 am
content: This is how you would get.. pour-able liquid that can soak something (like a freeze spray does) from a N2O containerHe has to freeze it in a dry ice or liquid nitrogen vat. In that form it might be a effective coolant.your not going to be getting liquid out of those tanks if they are at room temp. The pressure is too high. It boils too fast.Butane is -5C and propane is -40C boil point and the pressure for liquefying it at room temperature is much lower. Butane is like 16psi, propane is maybe 100 and propane is already getting very 'violent' to remove from a room temperature tank. Compare this to 900psi nitrous tank. With this kind of liquid you can transfer it into another sealed container OK but its not like you can get it out of the bottle like you could with butane or freeze spray togentlydrip or soak something with it.I want to see you use a nitrous cartridge or tank to freeze something in the same way you would freeze it with a normal freeze spray. At the doctor he will have a liquid nitrogen syphon which takes it out a dewar via a light pressure or even a push pump where it is already cold enough to be 'stable' for doing wart 'cryosurgury'. But no one is going to be getting liquid gas from a high pressure tank @ 900 psi, and not on a circuit card, not for a short burst. Maybe if you wanna rip the chips off with high pressure or somethingYou can probobly get it to self condense so you can drip it if you waste a whole bunch of gas to cool a heat sink of some kind built into the nozzle, maybe that is OK for a rocket but its ridiculous to plan to do that for a PCB . I still think its a ridiculous proposition.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 04, 2025, 09:53:00 am
content: @copperconeYou can pour liquid nitrogen (bp ~ -196°C) readily at normal room temperatures and pressures. N20 boils at -88°C. It can be poured. Propane (bulk) is delivered in liquid form and sold by the liquid gallon.

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 10:15:49 am
content: Poured from a dewar which is it cold in already, as far as I know. From what I have seen with high pressure tanks is that you won't be pouring nothing out of them.. the temperature of those dewars is already -270 insidea pressurized storage tank is at room temp all the way throughIf you put that tank upside down and opened it, you would still have 900 PSI there. And I would be really not want to cool cheap chinese pressure tanks to low temperatures...... or get pressure regs cold.. or a cheapo tank valve cold. Are they even stainless steel? (which has better cold behavior, if its proper). And pressure regs typically have rubber in there.if you empty that tank through a cryo condenser and c collect it in a dewar then it should be easy to pour or dispense. but not from the high pressure tank.THose big n2 dewars might have a light pressure on them, with a small regulator, but its still cold in there. If you look at LN2 lines on physics things, they are well insulated, so the cold N2 does not heat up too much from going through the lines and stays coldIts easy to pour liquid propane into another tank because nothing releases the pressure, it pressurizes everything to a pressure where its a happy warm liquid (in the tank only) so it can flow by gravityopening high pressure tanks without a reg isscary

author: jpanhalt
author_rank: Super Contributor
timestamp: July 04, 2025, 11:10:54 am
content: @coppercone2You are ignoring how liquid nitrogen (LN2) is stored and used by consumers. In school, I kept the main trap for my high vacuum system system cooled with LN2 for days, even weeks on occasion. On-site storage and traps were at atmospheric pressure. LN2 has a relatively high heat of vaporization (compared to liquid helium). Sure, some is lost, but it is far from immediate. The greatest danger we faced was if there was a large leak (e.g., a stopcock was partially open) and oxygen would condense in the trap.

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 07:24:35 pm
content: what pressure did you keep your big LN2 tank at. From what I understand they are like <10psi. The big barrels (dewars) people wheel around.I have yet to see anyone working from high pressure N2 tanks.You d o realize room temp LN2 tank would be... 40,000 psi. 10x more then a welder bottle of compressed nitrogen.. you are talking like... 12 inch steelwall thicknessfor continuous safe storage in a tank of substantial diameter. That is around the pressure reached in the barrel of a firing M16 . If you wanted to get liquid out of it, you would need to deal with liquid that wants super flash boil propelled by 40000psi.Not sure I ever saw a storage vessel that can handle 40kpsiWhat I have seen at research places for He or LN is a big ass super insulated dewar that is filled with very cold liquid that loses maybe 1% of its contents per year to stay cold through a suspicious vent that is frosted over when its 105F outside the physics building, and they transfer cold liquid into the mobile dewars for experiments that lose maybe a few percent of their contents per week.

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 07:44:35 pm
content: these people can make you a room temperature LN2 storage bottlehttps://www.hydropac.com/pressure-vessels.htmlsomething like this, but you would also need a very special gas regulator

author: thm_w
author_rank: Super Contributor
timestamp: July 04, 2025, 08:39:43 pm
content: Quote from: coppercone2 on July 04, 2025, 09:17:38 amIt should be possible without blowing ICs off the board:https://www.compoundw.com/products/compound-w-nitrofreezeYou seem to be mixing up nitrous oxide and liquid nitrogen. Liquid nitrogen can just be poured from a dewar as mentioned, but the storage loss makes its impractical. I still think CO2 and N2O might be viable options.

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 08:49:26 pm
content: OK the nitrofreeze might be actually using the sponge on the end to act as a condenser. It has low thermal mass so it rapidly gets cold. I did not think to put a sponge on the end. The sponge also acts as a restriction for flow, which is good at 900 PSI. That looks like a durable felt tipHave you actually tried to see if you can actually get liquid to get on something, or if the sponge part just gets really really cold?By design I would think the wart remover would want to confine as much cold to the sponge area, so it focuses the cold on the wart only. If it could actually drench your finger it would be dangerousexcessive 'spot cooling' of a IC might lead to a fracture. Normal freeze spray coats and relatively uniformly cools the whole chip

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2025, 09:09:35 pm
content: Quote from: thm_w on July 04, 2025, 08:39:43 pmCO2 plus acetone daubed on with a cotton wool bud was a recognised technique used by my doctor

author: Gyro
author_rank: Super Contributor
timestamp: July 04, 2025, 09:44:04 pm
content: Quote from: tggzzz on July 04, 2025, 09:09:35 pmAn IPA soaked swab swung rapidly in the air was the technique used by my dentist when I was a kid. If only I'd realized that it wassupposedto hurt when applied to a chipped front tooth, I would have saved a lot of unnecessary pain!

author: jpanhalt
author_rank: Super Contributor
timestamp: July 04, 2025, 10:32:23 pm
content: Quote from: coppercone2 on July 04, 2025, 08:49:26 pmSadly, I find it hard to decipher what you are trying to say. The use is a swab dipped in LN2 has already been described (Post #16). That is well established and is several decades old. There's no "might" about it.

author: thm_w
author_rank: Super Contributor
timestamp: July 04, 2025, 10:46:36 pm
content: Quote from: tggzzz on July 04, 2025, 09:09:35 pmYeah I think its clear by now these are all used medically, just debating on electronics use. Which is probably unnecessary, human skin is more fragile than a typical IC.and LN2 on its own will make things brittle, but they won't spontaneously shatter just from being cooled, AFAIK.

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2025, 10:55:06 pm
content: Quote from: thm_w on July 04, 2025, 10:46:36 pmI'll put acetone on my skin, but not on PCBs nor plastic nor front panels.QuoteI think you'll find SMD components (especially ceramic) can be damaged by thermal shock, hence they specify soldering temperature ramp up/down times.

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2025, 11:04:47 pm
content: I got a spray can of compressed acetone and its a expenisve addiction. Works ALOT better for cleaning PCB from flux then IPA. But it evaporates fast and smells worse. Spraying it on a wipe and rubbing flux residue works like 4x faster then anhydrous ipaflux remover spray is a little better but that stuff really burns cashI am going to guess though, that in terms of chemical exposure, the acetone is less then the alcohol because... it works so much faster.

author: Analog Kid
author_rank: Super Contributor
timestamp: July 04, 2025, 11:22:14 pm
content: Acetone: for years I was convinced it was more harmful than any other hydrocarbons, because of its pungent odor and ultra-fast evaporation.Turns out it's much less harmful than other solvents, like naphtha, which smell more benign.Moral of the story: don't necessarily trust your nose. Read the MSDS.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 05, 2025, 12:33:56 am
content: acetone is not a hydrocarbon.

author: Analog Kid
author_rank: Super Contributor
timestamp: July 05, 2025, 12:37:06 am
content: Quote from: jpanhalt on July 05, 2025, 12:33:56 amOK: solvent then. (Technically a ketone.)

author: coppercone2
author_rank: Super Contributor
timestamp: July 05, 2025, 01:28:41 am
content: acetone does occur in your body but it might stress mucus membranes out and do damage to some tissues where alot of it passes through, as usual you need to vent itif you ever saw a fool work with acetone you might see a nose bleed if their hunched over something their gluing for hours, i.e. for gluing models preciselybenzene actually smells very pleasant, but is one of the more toxic solvents you might run into.

author: SteveThackery
author_rank: Super Contributor
timestamp: July 05, 2025, 10:52:39 am
content: Quote from: coppercone2 on July 04, 2025, 11:04:47 pmIm a big fan of acetone as a general purpose solvent, but unlike the alcohols, acetone will dissolve several commonly used plastics. So you have to be careful with it.

author: coppercone2
author_rank: Super Contributor
timestamp: July 05, 2025, 06:55:01 pm
content: After desoldering a chip clean with acetone, after soldering a chip on, clean with alcohol. that way there is a big free space and it at least saves you 1/4 of the cleaning timebut that is what i mean too, its so good as a cleaner that a rubbing a damp cloth cleans flux good. with alcohol you need to make a little pool, agitate it with a brush, and then dab it.

author: tooki
author_rank: Super Contributor
timestamp: July 05, 2025, 09:21:24 pm
content: I use a blend of alcohol and acetone as an inexpensive and effective PCB cleaner; it’s exceptionally good at removing flux. But indeed, one must be very careful with many components, since it’ll wash the printing (both text and color bands) off of many parts.

author: Mr.B
author_rank: Unknown
timestamp: July 06, 2025, 12:14:05 am
content: Quote from: tooki on July 05, 2025, 09:21:24 pmWhat ratio have you found to be the best if you don't mind disclosing?

author: tooki
author_rank: Super Contributor
timestamp: July 08, 2025, 05:34:13 pm
content: Quote from: Mr.B on July 06, 2025, 12:14:05 amI don’t use anything too specific. I just fill a wash bottle with an eyeballed mix of around half and half, so the actual ratio could vary significantly. I haven’t done any testing to find an optimal ratio.Straight acetone is an exceptionally good flux solvent, but it evaporates so quickly that depending on the cleaning method, you can’t actually clean off the flux-laden solvent before it starts drying back onto the board. The alcohol slows down evaporation (or perhaps is simply able to keep the flux in solution after the acetone dissolves it, even once the acetone is largely gone). So the blend is easier to work with, and if using ethanol, is also less pungent.

author: Mr.B
author_rank: Unknown
timestamp: July 08, 2025, 08:46:36 pm
content: Quote from: tooki on July 08, 2025, 05:34:13 pmThank you @tookiI will give that a try.