learning to weld

mtaqua

Member
Oct 7, 2006
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I finally got a welder (Clarke 130EN) and some metal working tools. Anyways happy with the welder so far, seems to work great. I went to a body shop and got a fender from a newer model car (seems to be thinner than the mustang body parts). Anyways I've been cutting it up a welding it back together, doing only butt welds. Welding sheet metal is not easy. But after doing it several times it is starting to look better. I learned a few things maybe some other first timers could use. Take it slow, allow the metal to cool. I've rushed everyone, but when it comes time to weld on the car I will go extremely slow, so the metal doesn't warp. Tack it over and over, don't try to weld more than a 1/4 inch at a time. Keep tacking until you have very small gaps then weld the gaps. When tacking weld a tack then move several inches away to keep the heat down. Something I want to try is to use a block of copper or aluminum behind the weld as a heat sink, I need to acquire the copper/aluminum. When smoothing the welds I found it best to start with the stone wheel on the grinder for the high spots then use the sand paper on the grinder to finish it up. When grinding/sanding watch out for to much heat (warp the metal). Hope this helps someone. Now to learn how to use body filler & paint.
 
You should NEVER try to weld a seam on a body panel. Even 1/8 of an inch can be the one to ruin the body job. I use to think it wouldn't be a big deal til my auto shop teacher back in high school told us to take 2 flat sheets of steel, lay them flat and then weld 1/8 of an inch to get them together. Afterwards we flipped the steel and ran a ruler acros it. Until you've actually seen it you would not think how much it can move, until you do your body work that is.
As for heat sinks, aluminum and brass work great as welding wire wont stick to it. Another really simple method is a wet rag on the back.
Another helpful hint, if you ever do have to weld a bead on sheet metal on a vertical joint ALWAYS go from top to bottom, not bottom to top. Bottom to top will get you more penetration for thicker pieces, but on thin material like sheet metal you will more then likely blow a hole in your work.
Hope these tips help you out. :D
 
You should NEVER try to weld a seam on a body panel.

All the old school car customizers would beg to differ as do I. It just takes a lot of practise and a lot of patience. No offence but your shop teacher didn't know how. There are still a few car builders out there that do it. Chip & Troy are the first that come to mind. Checkout the work Wayne did on SN65, the fenders, quarters & front pan are all done in metal. If I remember correctly the wheel flares are the wheel openings from a GM minivan.
 
Take a piece of copper tubing, hammer one end flat, and you have a copper spoon for backing up welds. The spoon doesn't act as a heat sink so much as it backs up the metal and keeps it from blowing out. You can weld seams, but you will get warpage, you need to hammer and dolly it while the weld is still warm. The Marcel's do this type stuff all the time.

mtauqa, are you running flux core or do you have gas? Gas is much nicer on sheet metal as you run smaller wire and you don't have cleanup.
 
gas w/ .23. I just started so I really didn't know much. Things improved pretty quickly as I practiced. I plan on doing a bit more practice before I think about welding on the car. (And buying some welding/body work books to read).

Andrew