I remember someone posting tech on filling holes using a MIG in conjunction with another metal rod which guides the flux into the hole area. I thought I saved this thread, and I've searched the TECH archives to no avail. Anyone remember this article? If you wrote it, could you point me to it? Thanks, Mike
Use a piece of copper pipe with an end flattened out on it. Back the hole with it, and shoot the wire into it. It won't stick to the copper, the hole fills fast, and you don't get "porcupines" on the backside of the hole. The copper helps as a heat sink, as well.
i just welded mine shut with a regular gas welder, don't know if i was supposed to do it that way, but it worked.
Also you can stick a nail in from the back and weld it from the front. Works on small holes and avoids burning through. Don't use a galvanized nail; bad fumes.
Not a problem if you have a lot of bodywork to do, but even with my small MECO torch (which is fantastic by the way!) it can shrink the metal and warp the panel. Sometimes this is just what is needed though. On an otherwise straight panel, I'd use the Mig and a copper backing plate. Much faster than a torch, as you have to let each hole cool down much longer with a torch.
I've tried brass and aluminum and they didn't work very well for me. The dissimilar metal melted and contaminated the weld. What I use is a big ol' chunk of steel I have. It is a piece of 5" round stock about 3" long... solid steel... I turn the welder down to the heat range for the sheet metal... I turn up the wire speed a tad... then I back it with the steel. The lower setting is not "hot" enough to penetrate or stick to the big ol' piece of steel... but it fills the hole like a bye-gum! I've done hundreds of holes this way... Sam.
if the hole is big enough that you need to back it with something, you need to make a plug for the hole.
so should it be approached like tack welding? get the wire against the rim of the hole and pop it. then go to the opposite side and do the same, repeating till filled -OR- just zap and fill? thanks. gotta do the chevy in time for the luau.
I have a peice of brass round stock,2 inch I think.I back the hole,and weld away.No problems yet.JMO.................EVIL
thats how I do it. but i kinda pop it in a half moon... let it cool... nuther half moon... let it cool...
OK, I pulled my head out and found the post I was looking for. Thanks for all the posts so far: http://www.jalopyjournal.com/forum/showthread.php?t=61876 Mike
that technique works really good for filling gaps too.. not that I've ever had to... I'm just sayin...
Wierd. Never would have thought to try that. I have used apiece of copper pipe with the end hammered flat though. I actually it used as a backer filling holes in my frame.
The backing in this case, is for the Mig wire to bend on. Of course there's a limit to how big a hole can be filled this way.
on a frame, or anything thicker than sheet metal, a buddy told me that you can tap the hole & thread a bolt into it, cut the bolt flush with the surface, grind smooth, weld & regrind.
I did about fifteen holes last night on the '55's firewall... I could not get the big ol' chunk-o steel into some places... so I used a brass drift. The brass splattered a bit... but I found that if I concentrated the wire directly onto the firewall and not let it hit the brass... it did ok. I never really paid too much attention to this... but I noticed that when the wire would hit the brass, there would be an arc between the firewall and the brass... causing it to splatter a bit. I had my buddy bob on the inside, and he was holding it tight... but the drift had defects on it. So I would imagine if I were to turn it down in my lathe, and then hold it perfectly flat on the firewall... I'd cut down on the problems. This is thin sheet metal... I'd imagine that a thicker frame would make this effect less common... We all find out little tricks along the way... that's what makes rodding so FUN! Sam.
Use copper as backing, NOT brass. From what I've experienced, the MIG will stick and react with the brass, but doesn't seem to do so with copper.
I used a similar trick on my fairlane when shaving it. my trim holes were 1/4"x5/16" so I just placed the tip of a 1/4" steel rod into the hole and tacked on either side (leaving jsut a nub inside and 12" or so outside the panel) then I used a cutoff wheel to trim it off near flush (this was on a corner) then filed flush and continued on.
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