frame repair + heat

[TravisH]

Thought I'd ask this here before I go do something stupid.

Why don't people use a torch to help straighten out a frame? I know on heavy trucks it affects the temper and properties and will lead to cracking, but I can't see it on a half ton? I don't see how heating a frame would affect it any more than welding (again, not done on heavy trucks)

[dennislbrooks]

TTT --I want to hear opinions also.

[jgrh64]

liability issues here, maybe ask a frame shop what the best approach would be.

[7T7]

It's a fairly common practice on the older vehicles at most body shops to apply heat to a rail, but they don't heat it up to a red glow. Most of the time the bend or kink can be hammered out while the frame is being pulled.
Like on our old trucks it's probably not as big an issue as the newer Hydraform frames on the GM & Ford trucks. Toyota recommends that no heat be applied when pulling their frames, and on these new frames for GM, its 90 seconds for 1500 degrees, I believe, You can check www.i-car.com and go to the technical section and it will tell you all about full frame vehicles and what is recommended.
Now as far as I'm concerned all the bag jobs I have done, where welding has been done on the frame, I have not seen any cracks or weak spots. Maybe I have been lucky. I think common sense prevails when you weld, don't get it cheery red in to big of an area.

[72CSTC5]

I can only speak of the GM frames. You can apply heat but they want you to keep it to a minimum. They want you to lightly hammer the metal to "vibrate" back the molecular structure of the steel back in to place. Cold pull where ever you can but we use heat quite often in our Chevy Dealer Bodyshop.

[71 lowrider]

I have worked in a frame shop for 36 years and I have been heating buckled rails and crossmembers since I started in the business. The process is the same as most procedures,use common sense and moderation,you will be alright.