more welding questions

[Porkchop]

I posted a while ago about oxy-acetylene welding. I have tried this welding since then. I am having some trouble with it though. I am using a book as an aid but it discusses mainly welding of thicker metals. I set the both the oxygen and the acetylene at about 4 psi and I get a good looking neutral flame (yellow outside and sharp inner blue flame). I can make a puddle but then it will just melt away and leave a whole. So I started using filler metal but my welds are coming out uneven between the two pieces of metal. I have been using a #1 tip which is .040", should I try a smaller tip? About how long should I expect to spend welding about 4". Does anyone have any advice for me, I am open to any suggestions. Right now I am working on patch panels on the body but will have to do all of the cab supports and some of the floor also - do you guys think that this welding will be strong enough for those jobs. Thanks for any of the help.
brad

[tom hand]

If you are going to do it with a torch, I would just braze it. 10 times easier than oxy-acetylene welding and plenty strong. I use to do all patch panels that way till I discovered the mig

[Porkchop]

What is the difference between welding and brazing? Would I have to get some different parts/tools for my torch?
thank you very much for the help
brad

[tom hand]

With brazing you are using a brass rod covered with flux... it's takes a lot less heat to get a bond with the brass...it is more like soldering. All you would need is some brazing rods, and any welding place would have them. Some people call it braze welding, but I'm an old timer and it was always call just brazing when I learned how. It is also great for cast iron... I have put many exhaust manifolds back together that way

[progress]

For sheet metal on our trucks 1/32 and less (.03125 in) use a 000 (#75 drill size) tip and run 0.5 - 2 psi oxygen and 0.5 - 2 psi acetylene. The inner cone should be a bout 7/32 inch long. I use this combo for 1/16 thick material as well. Use a water soaked rag to cool after you weld about 1/2 inch. Skip weld so you don't build too much heat in any one location. I use this a lot especially for tricky areas, especially where I can't get my MIG tip close enough.

Good Luck

[Mike C]

Get some 1/8 inch stuff to practice on. Once you get a feel for puddling and feeding the rod, you should be able to extrapolate to other sizes.

[ginter]

Excellent thread! Thanks for starting it Brad. I'm considering doing some of my own patch panel repairs in the near future and I can use this info.

Thanks to all that reply.

[ginter]

If you are going to do it with a torch, I would just braze it. 10 times easier than oxy-acetylene welding and plenty strong. I use to do all patch panels that way till I discovered the mig

Just curious, but I've heard from some folks that MIG is not the preferred method for doing body work. Then there are others that think MIG is fine. Sounds like you prefer it to gas. How come?

[71gmcfanatic]

Oxy-acetylene welding is way to hot for welding body pannels. A light mig welder is the prefered choice because it is much easier to do without warping the body pannels.

[OhioDan]

"Be Careful", and don't try to weld a long stretch. It will generate to much heat and warp and expand your metal. When you get to the end, the metal won't align up any more. Use short length welds, and skip around to different places on your patch piece. If it's a small piece, weld awhile, and then let it cool. I thought oxy/acet. welding was a lost art. Glad to hear it's still being used. Just my $.02. Oh yea, I have a torch set for sale. $350.00. Tanks included.

[Mike C]

Once concern about brazing is that it doesn't take paint very well. My dad and I brazed the rockers in my Jimmy 15 years ago and it worked well. Since the only brass was inside the door area, I didn't worry about it.