Plug Welds - Mig or Tig?

[strokedelky]

I am a welder by trade but don't do too much sheetmetal. I'm in the process of replacing the roof skin on my El Camino (had a sunroof) and I was wondering which would be better. Mig or tig for the plug welds? I know most do it with a mig but was thinking tig may be a little less work afterwards (no welds to grind down). What do all the experts here think on this?

Thanks, Darren

[72chevellephil]

use mig,the tig will warp the hell out of any large panel you weld up.tig is the worst for plug welds.phil

[strokedelky]

Thanks, 72. I was kinda thinking like that just thought it might save a little grinding afterwards. Oh well, no big deal.

[Taylor1969]

Once you get in a groove grinding isn't all that bad.

If you prep well and setup the welder plug welds with a mig shouldn't be that bad. Just make sure to use a punch to make a bunch of holes and start welding.

[ahowudoin]

I never would of thought that tig was that hot. I thought it would have been better, Just take longer. Guess you learn something new everyday.

[Duesey2]

I have a tig and mig and have experimented with an infrared gun after each when spot welding. They both emitted the same amount of heat after several experiments. The tig is easier to dress out though. Mig is much faster for me and I don't have to mess with a foot pedal. I use the tig on delicate areas.

[chdnny]

I have a tig and mig and have experimented with an infrared gun after each when spot welding. They both emitted the same amount of heat after several experiments. The tig is easier to dress out though. Mig is much faster for me and I don't have to mess with a foot pedal. I use the tig on delicate areas.

even if they were the same temp wouldnt the tig have a bigger heat afftected area?

[MonzaRacer]

Tig hotter than mig, not if you have control of the weld.
Heck I would rather see a sheet metal part tiged over mig anyday.
Mig is simply faster in the filing part.
As for heat if you think its gonna be hot NAPA has a spray gel heat blocker that isolates the weld area very well I got one bottle off of the MATCO truck but it has since been discontinued. But NAPA selsls it in the Balkamp book.
If you can weld 2 razor baldes together with a tig how can it make a "hotter" weld or cause warping?
Never seen it and if your a welder you know how to control your heat for the weld process.
Good luck.

[hotrdblder]

tig is not hotter, when tig welding you have the heat on the material for longer periods cauing the heat to get out further then stich welding with mig, i like to do 3-4 tacks to form a stich, but 99% of the time i am doing plug welds/glueing as i replace the entire panel, there is a reason oems used pinch welds etc

[strokedelky]

Well, just to let everyone know I got it all finished up on the weekend. Most of the plug welds were in the front and rear window openings and along the drip rail. I played around a little bit and found for most MIG was preferred but there was some welding needed on the roof skin itself above the windshield and TIG was my friend. Nice small profile and a narrow heat effected zone with 1/2"-3/4" long stitch welds. A 36 grit disc on the angle die grinder made short work of the welds afterwards. Thanks for any and all replies.

Darren

[derekf]

Darren, do you have in-progress pics of the roof replacement? I'm in the same boat with my Camino and its sunroof.

[Taylor1969]

Darren, do you have in-progress pics of the roof replacement? I'm in the same boat with my Camino and its sunroof.

most of my pics can be found here...

http://s205.photobucket.com/albums/bb172/taylor1969/

[cheapthrillz]

Im not sure who makes it, but you can get a thumb amp control that is much easier to work with than the foot controls (my opinion).

[rich-allen]

When welding with tig, the surrounding material is almost three times hotter than any other type of welding.
Weld deposit is instantaneous from a mig. The surrounding material is affected as the heat dissipates.

There are instances where tig would be a better option but this is not one of them.

Finally a thread I can relate to.

[hotrdblder]

When welding with tig, the surrounding material is almost three times hotter than any other type of welding.
Weld deposit is instantaneous from a mig. The surrounding material is affected as the heat dissipates.

There are instances where tig would be a better option but this is not one of them.

Finally a thread I can relate to.

exactely

[parsonsj]

Thumb controls do help in awkward positions, but they have one drawback (at least for me): rolling the control affects the tungsten location and arc. Perhaps my technique needs work, but I've never had much luck in small amperage changes while the arc is struck.

jp