I have a Surly frame (4130) with a pretty bad kink in the downtube. Its probably shot, but I'd like to try to bend it back. Does it make sense to heat the steel before cold setting? Not necessarily with a blow torch - I was thinking of using my heat gun which can easily get it hot to the touch, but not red hot by any means. Would that help?
I know the various risks and problems from reading other posts and previous experience.