I know very little about TIG welding.I bought an aftermarket rear sus.for my truck.the truck is on a jig and the rear sus.has been tacked with MIG.The finish welding will be TIG, by a pro. Have i done more harm than good,by tack welding in MIG.

cool thanks.

dont have a tig welder here but i gotta hell of a big mig. we have built frames amd everything else you can think of. why is tig now the only way to go when mig was it before. someone with a gun in his hand that knows how to weld can weld a frame up just as good and strong as tig welded.imho...

Re: bad welds
 

I have done quite a bit of TIG welding so here is my opinion on a couple of things asked here.

I believe the issue would be if the whole thing were MIG welded and then ground down / or not, then TIG welded over because the TIG is such a smaller weld bead that you would not get weld penetration to the base metal only into the weld already there.

I think because moly tubing is so much more prevalent than in the old days. Tig does provide a smaller nicer looking weld in the right hands and MIG is not recommended on moly even though it can be done. It is a little harder to tell the penetration of a MIG weld also.

Curtis

10-4 on the moly and mig, unless you for sure know what you are doing, i would stay away from any high stress areas, with mig welding and moly tubeing.

Could be either, but you weren't wrong. It can be tacked with MIG and finished with a TIG.

Curtis

i myself fixing the bubble gum-use a mig.I was asking a different question.sorry.Now im not a pro.but decent with a MIG.Watching pros. on TV and such i seem to see them MIG the frames then TIG the cage.I'm a collision repair tech and fix wrecks all day long.But welding a full frame or a cage no.I'll leave that to the pros.I stand behind my repairs.but don't feel comfortable roll testing a cage that i welded.
I'm building a 98 gm regular cab with a 10 foot box dually,twin roots blowers from a 3.8 liter 6.6 duramax.The rear sus is a 4 link bag kit.I'd rather ask guys who do this all the time rather than the smuck at the local donut shop.Thanks again fellas.

Re: bad welds
 

well curtis thats a good answer. and you are right about that. but ive built frames and for hotrods and racecars with my mig and we have them all stand strong for yrs. i made a roll cage back in the mid 80s that got a true test in a 57 chevy ,buddy rolled his streetracer at 100 mph and walked away with a hell of a headache but he walked away. yeah tig is pretty but is it really stronger. that doesnt make any sense for it to be stronger if you really break it down.