Welding sheet metal...

Lifted79CJ7

So who wants to give some tips on the best types of welding for fixing sheetmetal??

FSJer

recently came across a product called "heat sponge", saw it in an autobody magazine . You apply it beside where your going to weld the panels togehter , and go for your life with a mig welder . you normally do a heap of tack welds to prevents warpage, but in this review they cranked the mig up to ywice the output you'd normally do it on and after they finished , there was no warpage as you clearly see it. Amazing stuff.

i think their website is called www.usaweld.com

FSJer

check out www.eastwood.com

tyrodtom

Stuff similar to the heat shield compound has been around quite a while. It doesn't stick very well on vertical panels, for it to work well it needs to be close to the weld, on a vertical panel the liquid in it runs into your weld, not good. What a very skilled welder can do with a mig as far as speed and welding heat are a far cry from what most people can do. I almost always start in the middle and work from the center out,with tack welds, even with heat compound. Most of the welding you will do on any car will be vertical. I've been mig welding for over 20 yrs.

Mudrat

Could used this stuff when I was rebuilding my rockers :smile: I was trying to keep it fairly smooth with tack welds and hammer finishing :shock: Well, I can tell you it's been a learning experiance - which is one reason I took on this project, teach myself some things. Pat

tyrodtom

One thing that is important when you weld with any method is to have the equipment set so you don't spend too much time on each weld, the longer you take the more the heat will spead and weaken the surrounding metal. When you hammer the weld you are actually ( if you're useing a hammer on one side and a dolly on the other) compressing the weld, forging it. A mig weld bead is harder right from the torch because of the shielding gas, there's fewer impurities in the weld. When you were talking about hammering the weld were you talking about acteyline torch or a mig welder. I've wondered if it's a good idea to hammer weld a mig welded bead, you might end up with the area you hammer welded being less flexible than the metal around it. Got any metalurgist handy? I noticed long ago the bead from a torch weld is softer than the bead from a mig weld.

Mudrat

tyrodtom wrote
When you hammer the weld you are actually ( if you're useing a hammer on one side and a dolly on the other) compressing the weld, forging it.
A mig weld bead is harder right from the torch because of the shielding gas, there's fewer impurities in the weld.
When you were talking about hammering the weld were you talking about acteyline torch or a mig welder.

Tyrodtom - yup was Mig'n everything. I set up some coupons and practiced with the 16ga I was using just to get a feel for the heat and penetration
I'd run a short bead and dolly the weld, bead/dolly, bead/dolly. Finally just said screw it and ran about a 1" bead, go the other side of the run with a bead working out from the middle about 8-10 inches between beads then let it cool before going back and connecting the dots. I found the hammer and dolly wasn't doing like it showed in the books or video, so I used a flap wheel and smoothed them out. I got some distortion, but hey! It's a Jeep :wink: It's fine for a trail Jeep, but not something I would do on the GW or the 56 T-Bird mama-san wants though :oops:

I rebuilt this whole 'B' piller, rocker, p-side floor and the upright area where the roll bar mounts, and the whole rear deck (rolled in the stiffeners too!) using this method. You can see it's not perfect - but there is NO bondo at all on this CJ!!!

Pat

tyrodtom

when you hammer weld you hammer when the metal is red when it cools down to where you can see no color you quit hammering and cool the surrounding metal with a wet rag. A mig weld bead doesn't hardly stay red long enough to hammer weld. Even if you got every thing set up so you can go from gun to hammer/dolly quick, it's pretty hard. Maybe 2 guys one hammer, the other weld. But if you want to hammer weld it's easier with a aceyline torch.

Mudrat

tyrodtom wrote
Even if you got every thing set up so you can go from gun to hammer/dolly quick, it's pretty hard. Maybe 2 guys one hammer, the other weld. But if you want to hammer weld it's easier with a aceyline torch.

Agree - that's why I said screw it :roll: Still working on the technique and getting the gas welding bit a little more under control. I tend to over heat for some reason before my puddle gets right :-| Too big a tip maybe?? When I get time to get back to that part, I'll work on it. For now the body work is done and I'm trying to finish the axles.

Thanks for the tips though - keep'm comming :t: (Jack's gunna need all the help he can get =D> )

Hi Jack :sa:

Pat