Welding and using a cleaning agent first

[safari57]

Many of us do basic welding on our trailers as part of the restoration and on going maintenance. The following is good information to be aware of. An experienced welder almost lost his life because of a simple to do mistake. Worth the read.

Brake Cleaner = Phosgene Article

[Splitrock]

Good to know, Thanks!

[starcraft]

My first welding job well once part comes in. I was thinking of using brake cleaner to get all oil off first. I wanted to primer the part first and leave small area to get ground and also 1inch of the part to weld bare. Wonder if this is ok to do. Can I hold piece into position and do quick 1 second spot weld to hold it. C clamps will not do job or I am not smart enough to figure way to temp attach to weld.

[safari57]

Your local welding supply store can tell you what to use for a spray cleaner. Your health is not worth the risk, get the right stuff to start with.

So far I've been able to get by with a wire brush or a wire wheel on the dremel in really tight spots to get enough area clean for a proper weld.

[Splitrock]

I have a small nozzle for my sandblaster that I can cut a fine line with. I mostly use sand to prep for paint. The wire brush and grinder is the way I've used in the past. I have used sand followed by the grinder on past jobs. I don't weld much anymore. In fact I try not to.

[perryg114]

Brake cleaner is overkill. Any type of Chlorinated solvent including all the refrigerants are bad news when heated. He must have vaporized a lot of the stuff to get that screwed up. I thought they had banned this stuff. The Redstone Arsenal including the NASA areas have several super fund sights where the ground is contaminated from many years of using this stuff to clean rocket parts or whatever. There are also areas with mustard gas and nerve gas that were buried before we knew better. Every time they have to dig up the ground it is a major ordeal. Alcohol is a much safer degreaser and what you don't use cleaning you can drink.

I can't imagine a trailer having enough grease to worry about. I use GUNK to clean up greasy areas then just hose the stuff off. It does not smell good but it won't kill you if you heat it. It is basically paint thinner mixed with some detergents.


Perry

[Kevin245]

Originally Posted by starcraft

My first welding job well once part comes in. I was thinking of using brake cleaner to get all oil off first. I wanted to primer the part first and leave small area to get ground and also 1inch of the part to weld bare. Wonder if this is ok to do. Can I hold piece into position and do quick 1 second spot weld to hold it. C clamps will not do job or I am not smart enough to figure way to temp attach to weld.

Not smart enough? Don't sell yourself short starcraft. Your weld idea is right on target. Allow me to digress momentarily if you will.


What you're referring to as a "1 second spot weld" is actually a tack weld. Tack welds are typically used to fit-up parts for positioning prior to welding. After the tack weld(s) cool you can adjust the part fit-up as needed in preparation for welding. They are small enough that they can be broken if the part needs to be repositioned.


Brake cleaner will certainly remove grease but the residuals should be of concern. It is important to remember that whatever is on, or near the area being welded will receive significant heat input during the welding process and may smoke, or even flame up. When you are welding you're usually right in the thick of things so air quality should be a concern.

If the part has a light oil coating you can use regular soap and water for cleaning. Just make certain to dry the part afterwards. Should any flash rust occur, a wire brush, grinding disk/pad, or emery cloth should take care of that. When I encounter significant grease or grime, I solvent clean, then soap and water wash before welding, otherwise I usually just hit with a flapper disk and go from there.

The key is to have the part reasonably free of grease, oil, rust, water or other porosity generating materials. This includes paint and mill scale. The intent is to have a dry shiny metal surface to weld on if possible. Once the areas are clean tack weld the part into position.


Not wanting to highjack this thread I encourage you to start a new thread if you have more questions on welding. You may want to reach out to ND10CentCan, or Minno as I seem to recall them sharing some of their restoration experiences.

Best of luck,

Kevin

[Nuvite-F]

Originally Posted by starcraft

My first welding job well once part comes in. I was thinking of using brake cleaner to get all oil off first. I wanted to primer the part first and leave small area to get ground and also 1inch of the part to weld bare. Wonder if this is ok to do. Can I hold piece into position and do quick 1 second spot weld to hold it. C clamps will not do job or I am not smart enough to figure way to temp attach to weld.

You didn't say what welding process you were using--stick/MIG/TIG but I'll answer your questions the way I would do it with old fashioned stick welding.

As I visualize this job you will be running mostly vertical welds where the outrigger joins the longitudinal frame member, is that right? Are you experienced at that sort of thing? Out-of-position welds (anything but down) are a little trickier than downhand.

I wouldn't use any kind of solvent to clean anything, just wire brush it good. If you are using a high-penetration rod like 6011 it will go through a little oil or even paint without hardly noticing it. Cleaner pieces starting out will give you a cleaner weld, though.

I wouldn't paint the outrigger before welding it. It will most likely get hot enough to burn off any paint for at least 3 or 4 inches from the weld zone.

Magnetic welders squares are handy for holding pieces in place before welding, but I often just hold the parts with one hand (wearing welder's gloves, of course!) and tack them in place with a couple of tack welds. (The new auto-darkening welding helmets are very handy for this!) Examine carefully after tacking, and if the piece is where you want it, weld away. If not, you can break the tack welds and try again.

If you don't have a lot of experience at this, I would suggest mocking up a similar situation out of scrap and trying it before welding on your trailer.

Good luck, and have fun!
.

[perryg114]

I use a cup brush on an electric angle grinder. It will get most of the funk off. Also you can get sanding wheels and cutoff wheels for the same tool. The grinding wheels will cut through anything. Rust is the main thing you want to get off and any paint. Galvanize steel is bad news. Always grind paint and and coatings off metal before welding and have some air flow. Most burnt organics and anything Chlorinated is bad news. I am glad I don't weld for a living. It has got to take some years off you. You are exposed to metal gases, metal oxides (worse than metals), carcinogens, and out right toxins. It is a good idea to wear an auto paint quality mask with carbon canisters while grinding. It would not be a bad idea while welding. If the guy in the article had the right mask it would have protected him. I can’t wear the paper things because they fog my glasses. Paper won't protect you from organics just particulates.

Perry