[R-mm]

Hi all -

Can anyone recommend a good technique to keep parts square while TIG welding? I have been tacking, using various magnets and trying to distribute the heat evenly by stitching one side then the other an inch or so at a time. Is there a clamp that would help me or short of a fixture will the heat always win?

Finally - any tips on how to avoid cupping as I exaggerated in the last pic? I've tried clamping the parts to the welding surface and again going somewhat slow but they always cup a bit.

Welding at 190 amp, Everlast TIG, pure Argon. 3/32 rod, 1/4in mild plate.

Photo Jul 25, 4 29 09 PM.jpg (1.8 MiB) Viewed 2830 times

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[Coldman]

If you have a bunch of them to do, tack them and then bolt the square plates back to back before welding them out. The heat stresses from one side will oppose the heat stresses from the other side. Unbolt when completely cool and they should come out straight.

[Spartan]

The heat will always win. There are things to help you in the battle, such as heavy duty fixturing and opposing the stress as both you and Coldman mentioned. But these things only help...they won't lead to perfection.

Welding is an imperfect form of joinery. You won't ever get close to machining-level tolerances during most non-automated welding, and this is generally known and accepted in the industry. If you need very tight tolerances, the typical order of operations is to weld first and then machine the assembly to tolerance as a second operation.

[R-mm]

Thanks guys. I watched cody and others videos and believe im understanding that its heat distribution and sequence not brute force thats going to carry the day.

[Dimestack]

Tack them up and place a shim under the plate that is only as wide as your vertical plate. If you’re welding .250 material use .250 wide shim. Stick that directly under your vertical piece and clamp the part to the table so it bends down. Weld the part and let it cool before release clamps. Thickness of shim will be determined by your heat input. Perhaps start with some .060 and check results. If it’s to much go down, not enough go up from there. By the end of the job you’ll have it just right. I hope there’s plenty to do. It’s totally worth the time to figure out if there’s more than a few. Straightening isn’t fun so minimize how much you have to do and the time it takes to do it.