welding sheet metal - first attempt didn't go so well

[idosubaru]

for thin sheet you won't be doing much welding in a row

that's what i was attempting the entire time, i thought i would have to do that to get a proper pool and bead...so yeah i was just burning through it the whole time.

 

so you "spot weld" it basically - then how do you properly fill in the gaps?

bondo? i thought all metal would be better than bondo for longevity, etc.

[djellum]

from the factory most of the welds are spot welds, but prob not what your thinking about. resistance welding is putting 2 plates together and they put it in and electrified clamp and run current through it. the squeeze pressure and electricity welds the 2 pieces together in the center. you can see it on the tabs of metal sticking off of the car like the line on the bottom below the car. there will be little circles along in a row.

 

car sheet metal is setup to be welded this way so its not really set up for normal arc welding.

 

the way i would attempt it (I've welded a lot, but not on cars). take a patch panel shaped like a circle just for example. use some magnets to hold it in place. put a small dot weld on the edge, just one trigger pull, zap, just to get it stuck together straight. then go to the opposite side and bend the upper weld to realign the piece, and same thing, zap another dot in there. keep going this alternating, 90 deg or 180 deg around, until its all doted up with a dot every inch or so. then you wire wheel the whole business since your using flux core. you may have to replace some of them since flux core doesn't work as well for this as hard wire.

 

now you grind out the bulge on 1-2 of the spots you have put in, so they don't affect what your welding (gone is ok, minimal is better). the rest of the dots will hold it in place. start on a unground dot and weld a strip. how far is up to the metal, try all the tricks, drag the wire, anything you can do to reduce the heat. the weld may only be a half inch or even less. You walk around the edge going back and forth to the opposite sides to spread the heat just like you did with the dots. stitch it all together, grind it all back down and fix any holes.

 

hard to say when i can't see it, but give it a go on some scrap and list the problems here.

[idosubaru]

Are you welding beads or spot welding it together?

 

Don't weld beads, just stitch it with spots.

this worked perfect! thanks! it was actually really easy as soon as i quit trying to lay a bead on the thing. spot welds every couple of inches and it's done!

 

thanks a bunch!

[Mykeys Toy]

This is a very interesting Thread. Some good info for noobs and what not to get if you can afford it.

[Crazyeights]

Ok, so what is the best way to fill in between the spots before starting body work?

[Mykeys Toy]

SO I was perusing CL and ran across a video link which got me to this.. I don't think it will help with sheet but may improve your technique for other stuff... I found it interesting but I have only scratched the surface of what I don't know.