Straightening Tubing With Heat

Sometimes you do what you can to prevent metal warpage when you weld and it still happens. What to do?

Here's a little tech tip.

I welded up my frame horns, and half way through there was a loud BANG that scared the bejezuss out of me. One of my tack welds popped that was holding everything straight.

After I was finished, I checked square, and both horns were racked to the left.



Here's the trick: Use a cutting tip in a torch (a rosebud tip doesn't apply enough of a precise heat unless the piece is massive) to heat the convex areas of the warp in small areas at a time.

I started with two golf-ball-sized spots; one outside of the PS, one inside of the DS. Heat to cherry red, then just let it cool completely. As it heats, the warp will get worse, but as it cools, it will shrink back beyond where it started. I checked after the first cycle and it moved a little. I did it again, heating a vertical strip this time, since the first attempt didn't do much. Better to take baby steps than go too far.

Here you can see the grey areas are where I heated.



I checked again, and bingo. The camera is making it look crooked, but it is straight.



At one shop I worked at, we used to straighten bent garbage truck frames with this trick, but it took 3 torches going at once to heat their massive frames enough to work. This also works on bent axle tubes. With patience, it is a very precise method.

 

Frigging awesome.

As for steel stock. I have gotten some straight from the supplier not straight on several occasions.

 

I used a 8 foot long 4x4 and cold bent the twist out of my frame horns worked very well had my son lever one way while I levered the other. Result dead straight frame horns..

 

I have seen I beams straighten . with rose buds and a water sprayer . oil industry construction

 

I need a shop assistant.

 

you definitely need one of those.

 

"Flame Straightening."
My secret weapon.

 

It's slow. You could watch it and not see it.