Ive just started working on my truck and it looks like im gonna have to be doing some sheetmetal repair. Ive got my dads old miller electric mig welder. Any tips on how to get a good weld and a good clean finish on thin-tin? Ive never really welded before except praticing on scrap but im gonna have to start some where.
do a search, there was a post just yesterday about this same subject. One reply gave a good website to check out: www.mig-welding.co.uk/tutorial.htm
-Keep the metal clean, I use a wire wheel and wipe with lacquer thinner. -Keep the nozzle and tip clean. -Make sure you have a good ground, I use some vise grips to make sure it is tight. -Listen for any popping, and adjust your wire speed until you hear the sound of eggs frying.
If you are going to be doing sheet metal you cant run beads you have to tack the panels to aviod distortion. use compressed air or a wet rag to cool down your welds. its a verry slow process but if you get in a rush you make more work for yourself later. also when grinding welds you generate a lot of heat so keep cooling it down. and last you will need a good hammer and dolly to finish out any lows and highs in the pannel.
This topic came up on MetalMeet today as well. Here is the link: http://www.metalmeet.com/forum/showthread.php?p=148740&posted=1#post148740
Alot of good info in this thread already keep a spacing of no more than 1/16 to get good penetration, the better your prep and fit up the better your end results will be. As said before it is just a buch of tach weld spaced out and eventually over lapping. there are a load of pics on the HAMB to give you a good I dea of what it should look like. But practice on the old steel you are removing cut the old peice in half and weld them back up to set your parameters on your welder, AND GOOD LUCK
Make sure you get good mig welding wire . Not that cheap Chinese shit that has all the impurities in it. You'll know it the minute you use some.
Quenching steel hardens it. If you quench your welds, they are going to require more grinding (and thus more heat) because of that. Tack every inch or so, starting at the middle and working your way out. Then weld between the tacks. Grind and continue.
I never quench welds unless there is something nearby that would be damaged by heat. However, quenching at lower temperatures does not harden sheet meta. I have learned this using a shrinking disc. If you need to quench, wait until the metal cools a little bit first. this article might help: http://metalshapers.org/101/jkelly/index.html Also check out Randy Ferguson's excellent article: http://fergusoncoachbuilding.blogspot.com/ Nice volksrod by the way! John www.ghiaspecialties.com
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