Welding Tips and Tricks

I'm welding 72" x 6" frames from 0.375" stainless steel tubing with a 0.035" wall thickness. If you can imagine a trombone - the part that slides back and forth - this is what my pieces look like. They're lighting diffusion frames for the film industry.

These SS tubing frames weld into a 0.375" "handle" (which is really just a piece of rod sticking out from the frame. There are also one or two cross members on the tubing frame to strengthen the whole thing and help it keep its shape.

As I'm only welding on one side of the tubing, I am getting distortion along the length of the 72" pieces.

I have tried with some success to handle this by applying heat from my TIG torch to the back of the tubing, meaning, the side that was NOT welded. I simply hold the torch perpendicular to the piece and hit the pedal, taking care to not blow a hole by going too far.

I have also tried with less success to use a propane torch to replace the heat from the TIG torch (which tends to liquify the metal quite easily) but as this does not get as hot, I don't get results which are as good. The pieces are straightER but not fully straightENED.

Question: To reverse heat deformation from my original welding in this instance, do I need to apply the same intensity of heat to the back side of the welded piece to reverse the distortion? Is it temperature of heat that effects the straightening or duration of heat or none of the above.

This heat-straightening is an important part of my process on these pieces so any advice would be welcome.

Jon

If you only weld one side of a tube and distortion occurs (expected) then you can use flame heat to straighten it.

While heating, move the tube beyond straight then let it spring back. This will take some trial and error. But with a bit of effort you can get it very, very close.

Good. I'll post my results. I must say it's quite satisfying to be able to perfectly straighten deformed metal.