Welding work - Page 1
Forum section: electronics / beginners

author: jannie
author_rank: Newbie
timestamp: April 07, 2022, 08:24:14 am
content: I'm building a welding cart out of recycled metal from the scrapyard. I am Curious if any of you know of any product that will strip both paint and rust from metal. Trying to save some time sanding and grinding. what about Muriatic acid for this work...?

author: jpanhalt
author_rank: Super Contributor
timestamp: April 07, 2022, 09:27:13 am
content: Stripping both paint and rust used to be quite common. It is done with phosphate/phosphoric acid and with or without electrolysis.Alkaline phosphate solution (i.e., Na3PO4) is an excellent paint remover. A popular rust remover,Naval Jellyis based on phosphoric acid. It also removes paint. Some combination was used commercially for "tank stripping" (e.g., whole car bodies before restoration). Those baths are walso heated, but not particularly hot. I never asked the composition of the brew, and the shop near me is now closed. You can also do electrolysis in just phosphate to get rid of rust and paint.Be sure to note, those baths were for steel. Active metals like zinc and aluminum alloys are destroyed.EDIT: Here are two references I used.Andrew Westcotthttps://www.qsl.net/2e0waw/rust.htmTed Kinseyhttps://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm.

author: m3vuv
author_rank: Super Contributor
timestamp: April 07, 2022, 09:44:07 am
content: iv'e had good results with removing both(cant remember what its exactly called) electrolysys,basicaly stick whatever you have in a solution of salt water or diluted battery acid and connect the workpiece to neg and the pos to a lump of metal,i have mostly used diferent voltages and mixes of electrolyte ,start with say 1amp at 5v and see what happens,normaly the paint loosesn and rust turns to black slime that washes off,the good thing is tho in my experiance the parent metal remains as is unlike sand blasting etc,give it a try,use a plastic or non conductive container tho.

author: Whales
author_rank: Super Contributor
timestamp: April 07, 2022, 09:49:25 am
content: Electrolyte bath cleaning works really well on ferrous parts. Paint, grime, etc. Engine parts come out looking shiny and new. My father uses an iron rod as the 2nd electrode, large plastic drum, wooden beam + wire to hang the parts from and a 5V power supply I gave him (with a latching overcurrent/short-circuit protection I added). I can't recall but I think the water self-heats over time.From what I've read: beware using it with more reactive materials (eg aluminium), it may destroy your parts.

author: themadhippy
author_rank: Super Contributor
timestamp: April 07, 2022, 10:04:49 am
content: Quotewith the right disc , like a low grit flap disc, youll be down to bare metal much quicker than chemicals by the time you dipped and washed the parts off

author: jpanhalt
author_rank: Super Contributor
timestamp: April 07, 2022, 10:39:30 am
content: Flap discs may work on large, flat surfaces, but not so well on complex parts with nooks and crannies. They also produce dust and change the surface more than electrolysis does. Finally, if one uses phosphate chemistry, you can leave a protective coating.

author: MarkF
author_rank: Super Contributor
timestamp: April 07, 2022, 12:47:47 pm
content: A lot of the machinist YouTube channels useEvapo-Rust®to remove rust.Just soak overnight and wash off. I don't know how well it works on paint.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 07, 2022, 05:04:10 pm
content: I used phosphoric acid to clean snow blower parts that I was repainting. It's amazing how well that works, and the parts refuse to rust now, even where paint has chipped off. Recommended!

author: james_s
author_rank: Super Contributor
timestamp: April 07, 2022, 05:08:13 pm
content: I've occasionally used electrolysis using nothing more than baking soda in water. It does a decent job of removing rust, and often the paint will bubble and flake right off too, taking it all the way down to bare metal.

author: jpanhalt
author_rank: Super Contributor
timestamp: April 07, 2022, 05:40:18 pm
content: The main difference between baking soda and phosphate/phosphoric is that the latter removes paint and primes the steel to an extent (phosphated steel is somewhat rust resistant too). Soda doesn't do either unless there is rust under the paint that eventually makes contact with the electrolyte.

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 07, 2022, 06:03:32 pm
content: Twisted/knotted wire wheel on an angle grinder, work outside fully covered, with a face shield, and have breathing protection or a fan blowing clean air your way. Remember, this is why nasty scrap metal is cheap, no free lunch and all that.I've heard bad things about using muratic/HCl, forget the specifics but it makes ferrous metal more rust prone after cleaning.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 07, 2022, 06:18:07 pm
content: Normally I would sandblast the parts then powder coat them.

author: Brumby
author_rank: Unknown
timestamp: May 14, 2022, 03:41:59 pm
content: Quote from: jannie on April 07, 2022, 08:24:14 amWill do paint as well.

author: wizard69
author_rank: Super Contributor
timestamp: May 14, 2022, 06:36:48 pm
content: For Rust and Mill Scale you can go down the local grocery store and get some vinegar. Depending upon how bad the rust or mill scale is you may need to soak the item overnight. In any event this will strip mill scale and rust and leave a nice clean surface. It sometimes pay to give them a quick scrub with a bristle brush and to turn things over agitate every hour or so.In most cases this will not strip paint, or it hasn't for me. However if there is loose paint or rust under the paint, some paint will be removed.The nice part about vinegar is that is widely available. The local hardware store may not have a meaningful supply of rust remover. With vinegar you can buy gallons and gallons to easily fill a large soaking tank. So this is excellent for bulk de-rusting and scale removal that can be accomplished almost anywhere no matter how remote to chemical supplies.

author: Gyro
author_rank: Super Contributor
timestamp: May 14, 2022, 06:52:14 pm
content: Quote from: Brumby on May 14, 2022, 03:41:59 pmHoly Sh*t, that thing is handheld! Since when have you been allowed to wave a laser at the top end of Class 4 around?I thought lasers of anything like that power were supposed to be safely enclosed with guards, safety interlocks etc.

author: Nusa
author_rank: Super Contributor
timestamp: May 14, 2022, 07:12:07 pm
content: You ever notice how often grinding equipment is operated without the safety shields installed? What you're supposed to do has little relation to what actually happens, especially in one-man shops.

author: Gyro
author_rank: Super Contributor
timestamp: May 14, 2022, 07:18:15 pm
content: Yes maybe, but a grinder isn't going to instantly blind somebody who accidentally gets anywhere in the vicinity. A 2kW Class 4 IR laser will - if you get an incident reflection off a nice shiny piece of steel for instance!I don't understand how they can get approval to sell what does appear to be a handheld device.EDIT: Definitely handheld...https://www.laserphotonics.com/laser-cleaning

author: james_s
author_rank: Super Contributor
timestamp: May 14, 2022, 08:28:34 pm
content: Yeah I looked it up, 1064nm so it's a Nd:YAG laser, that's extremely dangerous as the beam is completely invisible but it will pass right through and be focused by the lens of your eye and it will reflect off many materials that reflect visible light, including the base metal you are cleaning. It looks like a useful tool but you sure wouldn't want it to be in the hands of somebody un-trained. At that power level and wavelength it only takes one mistake to ablate the retina from your eyeballs just like it's doing to the rust.

author: IanB
author_rank: Super Contributor
timestamp: May 14, 2022, 08:32:26 pm
content: Quote from: jannie on April 07, 2022, 08:24:14 amChemicals are messy, while sanding and grinding make it hard to get into corners.Maybe find someone nearby who does sandblasting and have all your parts cleaned that way?

author: jpanhalt
author_rank: Super Contributor
timestamp: May 14, 2022, 10:01:10 pm
content: Seems like comparing apples and oranges: commercial sandblast cleaning versus DIY.As for mess, I can do and have done chemical cleaning in a shop on my bench or even kitchen (very small parts). Sandblasting? No way. That is messy. Sandblasting has a place in the cleaning and refinishing business. It would be my first choice for a lawn mower deck, cleaning welds, and maybe for wrought iron railing (because of size). For most other things, I use chemical or mechanical. Why isn't sandblasting used to clean engines and transmissions before rebuild? It is more destructive, and it is virtually impossible to getallof the tiny gritty dust out. I have a 48" x 30" bead blasting cabinet with reclaimer in my shop. I use it only for such rough jobs as cleaning welds and some rusted parts that do not have bearing surfaces. Particle blasting with solid CO2 or bicarbonate is a newer method that has definite advantages over sand, glass beads, etc. It is good for paint.

author: langwadt
author_rank: Super Contributor
timestamp: May 14, 2022, 10:31:32 pm
content: Quote from: james_s on May 14, 2022, 08:28:34 pmEdd China the guy from the original "wheeler dealers" used one and also cooked a steak with ithttps://youtu.be/N8oakDbquJo?t=1868a believe the machine cost several 100k€

author: Nusa
author_rank: Super Contributor
timestamp: May 15, 2022, 04:11:11 am
content: Sandblasting is an excellent example of a tool that can cause serious health problems to anyone that's present without proper safety precautions. Where's the outrage? No worse than a hand-held laser tool in that sense.

author: james_s
author_rank: Super Contributor
timestamp: May 15, 2022, 07:03:31 am
content: Quote from: Nusa on May 15, 2022, 04:11:11 amNot even close. Sandblasting can cause potential health issues if you use the wrong abrasive and/or don't collect the dust properly but that's nothing like a 2kW laser that can cause instantaneous eye damage even from reflections off objects. I have a 1W visible diode laser and the spot on a wall is blindingly bright, it's a very dangerous toy, this is 2,000 times as powerful and completely invisible.

author: electromateria
author_rank: Regular Contributor
timestamp: May 16, 2022, 03:36:42 pm
content: I have a lot of experience stripping rust. I honestly hate it because I don't have the right equipment. I'm working on getting a high CFM compressor so I can sandblast parts in a cabinet. That's one of the best solutions.You could get a wire brush for an angle grinder. LOUD, time consuming and kicks up harmful dust - but effective.You can soak parts in vinegar or other acid - from my experience that works decently but you need to clean it perfectly, then neutralize the acid, then coat the metal with something or rust will quickly reappear.If you have a junk handheld sander and spare motor you could make a vibrating tumbler that you fill with sandblasting aggregate and ball bearings. For me this is the s-tier solution. It just runs and cleans parts perfectly on its own. No breathing in dust, no work - ZERO EFFORTThe downsides are that it's very noisy and potentially quite large depending on what you're cleaning.I made a small vibrating parts cleaner that uses an orbital sander and $4 plastic container (attached images of results). It works very well on rust and grime but not so well on paint.

author: themadhippy
author_rank: Super Contributor
timestamp: May 16, 2022, 04:20:15 pm
content: Quotesheer genius,added bonus is most sanders use velcro to attach the sheets so no need to make things permanent

author: electromateria
author_rank: Regular Contributor
timestamp: May 16, 2022, 06:33:34 pm
content: Quote from: themadhippy on May 16, 2022, 04:20:15 pmIt really is an amazing solution! There's a really nice satisfaction that comes from taking dirty rusty parts (most people consider it "garbage") and making it brand new again with zero effort. I learned it from this fella, his channel is worth checking out:

author: ConKbot
author_rank: Super Contributor
timestamp: May 17, 2022, 03:40:41 am
content: Quote from: MarkF on April 07, 2022, 12:47:47 pmNote that a lot of them are sponsored by evaporust, or at least some restoration channels are. Not saying it's bad, or the channels are doing anything wrong, as most seem to properly disclose the paid placement. But keep the facts in mind. If evaporust was going to ship me a 55gal drum of it to use, I would wouldn't pay much mind to price/performance, or any minor oddities it has during use.Now I will say what works to remove rust that I've used has been citric acid in hot water. Had a pair of scissors that build up rust between the blades. Dunk in a hot citric acid solution, and it ate up the rust fast... But it doesn't leave shiny metal steel, but instead a black oxide finish. Dry it off and oil it if that's your thing. If not, other treatments will be better. Scissors were nickel plated other than the faces touching each other and the cutting edge, which blackened and look pretty good now, imo.Citric acid can also be used for pickling/passivation of stainless steel. Eats the iron near the surface, leaves the chromium, which makes a passivation film that doesn't rust.

author: SilverSolder
author_rank: Super Contributor
timestamp: May 18, 2022, 02:18:42 am
content: Quote from: ConKbot on May 17, 2022, 03:40:41 am+1 for citric acid.Phosphoric acid is also amazing: it reacts with rust and forms a new compound that resists further corrosion. Phosphoric acid can be found in some paint prep products, I like Klean-Strip Prep and Etch, a little goes a long way.