I'm trying to TIG 1/8" aluminum sheet and am having trouble with the metal moving around from the heat. On the pic below, I clamped everything down, but the metal still started to warp after removing the clamps. Wondering if you guys have any pointers before I try it again.

 

make the box by bending it of one sheet and weld it at the corner might help. Flat surfaces tend to warp.

 

Yeah, it was just that the metal only comes in 12 foot sheets, and the total structure is longer than that, so a piece had to be welded in.

 

I would try to keep the sheet cool or add more sheets of aluminium on top and below it to absorb the heat.

I'd also try to weld fast and in smaller sections to utilize more efficiently the heat needed, minimize how much gets dissipated into the sheet and give it time to cool between welds.

 

Would

not work for heat warpage?

 

Compensate for warping by pre warping the part the opposite direction

 

How the eff does that thing work?

 

Yeah, that makes sense. I'll work on welding faster with less heat.

 

It's a metal shrinking wheel.

It heats the raised portions of the warpage, and the heat differential allows the metal to reform into its original shape.

They used to be used in auto body repair, after welding in a patch panel. These days, the panel is usually either replaced entirely or body filler is used, so shrinking after welding isn't really done any more.

 

This is incorrect. When you weld, the metal shrinks. A shrinking disc would make it worse. When doing sheet metal work, a high spot or "stretched" spot is shrunk down level with the rest of the panel. When you weld a sheet metal panel it will sink down, you then have to hammer on dolly the effected area in order to stretch it back to its original shape.

 

Would it help to weld smaller lengths?

 

to me it looks like your start/stops are waaaay far apart. i would def shorten those and maybe alternate which bead you are welding on.

 

And why would you add that small piece in the middle? Why not bend it out of a single piece of aluminum?

 

he already answered that ^

 

Ah ha

Could you reconfigure the design so you can weld on a corner?

 

good idea ^

 

thats what I was going to suggest, eliminate the dumb little piece and just run a single length from corner to corner.

 

After you finish welding, do you let it cool down before your release the clamps???

If you don't then that will be your problem.

You may try to weld the corners, but that will take more material, but it won't warp on you.

Stefan

 

Put a wet rag on the sheet metal when you are welding. When it starts to steam and get hot let the metal cool down. You can dip the wet rag in a bucket of water and help cool the metal down while you wait. Don't get any water on the immediate area you are welding though for obvious reasons. Also be very cautious of steam, some hot steam won't feel to good.

 

Thanks for all of the advice. After reading suggestions from this thread, I layed tack welds every few inches, clamped everything down really well, then welded in small 1-2 inch sections alternating between sides. Everything was good the second time around. Thanks guys!