TIG welding sheetmetal

So I've got a new Lincoln Precision TIG 185 here at work. From all the reading I've done, this seems to be a pretty nice machine.

I've been gas and MIG welding for a while but I have very little experience welding sheetmetal and no experience with TIG at all. I need to weld some rust repair patches on my tub and I'm wondering if anyone can give me some pointers with how to approach it. I think the best method is to cut the panel as exact as possible and butt weld it to the existing.

Any pointers out there?????

Thanks!

mruta

 

Are you asking about the welder or about the rust repair technique? Here's a good article about rust repair that may provide some pointers: http://www.autobodystore.com/door_rust.htm

Most patch panels are flanged somehow, either with a flanger or with a backing panel.

If I were replacing complete panels, I'd probably just use plug welds. That most closely duplicates the spot welds used on the original. If I were patching in the middle of a panel, I'd weld all the way around to avoid gaps and cracks later.

 

My question was geared more towards the welding technique and TIG setup.

I'd like to try to butt weld the patch panel into the side of the tub rather than flange, punch and weld it from behind if it all possible. With TIG, I know I've seen where people cut a panel to fit exactly and then it was butt welded without even needing the filler rod.

Has anyone here tried this approach? I know it would be easier to flange it and use plug welds from behind using my MIG welder but I never seem to do things the easy way...

mruta

 

I have done this with a torch and if done carefully makes a virtually invisible repair

 

I butt welded a few panals on my floor. I just welded a 1/2" spot, went to another area. Welded some more until the seam was all welded up. I had a little warping but nothing a hammer and dolly couldn't fix. I cut the floor so as to have the butt welded seam over the top of the floor support chanals, but I was replacing both floor and the support chanals.

 

I do a series of spot welds. Like Scott said above about 1/2 inch at a time then work the opposite end or other side. I do have some clamps I've bought that give me the right amount of clearnce for the weld. Very little warpage when I do it that way. Most body men I've ever talked to like butt welds better than overlaping the metal, they tell me with the flange or overlap your just asking for trouble with rust later.

 

David- which welding method (gas, MIG, TIG) did you use for what you described above?

I'm pretty decent with MIG but I think I could do better with TIG and a lot of practice.

 

Mig, but I used to do it with torch but you get a lot worse warpage and have to do more hammer work. I also keep a damp rag handy and lay it on the metal not the weld mind you just the metal just to keep the temp down. I think this keeps it from getting to warm and rippling.

 

Mike I use a tig at work, alot, I would butt weld it. It will take a lot of practice to get the heat setting right and I recommend using the smallest tip your stinger will handle.
I also use a auto darkening helmet. I am not an expert but if I practice a little and don't get in a hurry I do pretty decent, especially if I am in a decent open area where I can get comfortable and move the stinger where I need it and am comfortable using it. None of the welding on my frame was MIG'd it was all done with a Miller 225 Tig unit.
They offer way better control than a torch or MIG unit but take more practice to get good at and if used to long will also add a lot of heat to the part. With a TIG unit penetration is always top notch compared to other forms of welding.

 

I had planned to use a crimper until I tried to use it on the heavy gauge metal the Jeep body is made from. Yow! The butt joints worked good. I took a little extra time and some extra metal because of goof ups, but I made sure the new pieces were cut as precisely as possible, so there was very little gap. I started with a posterboard template, using it for a test fit, then traced it to the sheetmetal and tried to get it as exact as the template. On the bodywork, the weld appearance doesn't matter, since your going to grind off almost everything anyway. Just make sure you get good enough penatration on the weld and you should be good.

Jim

 

my buesness i do some sheet metal work with my tig, its somthing once you get the hang of it you will like the end resuslt, but the fit is more critical than the weld, you cant fill out of position butt welds with a tig unless you been doing it for some time, just practice ( ALOT ) and you will get it, this is using a ESAB 250 squre wave machine.
one more thing about tig is if your fit-up is sloppy ( gaps, dirty base metal and position of weld ) its harder to get a good end result, jason.