1sttimer
Over 1,000 Posts
Ha - the old "you're an engineer" card. Nice.
My knowledge comes from me sitting there with my MAPP torch for 4 minutes unable to get a red glow. I got the surface discoloration you referenced but with the lever in my vice and some good whacks with a dead blow, no movement.
Maybe it's the tip on the small torch I have? I don't have a MAP-Pro. Mine works well for 3/8" or so. Anything more and it's hit or miss depending on the cross section. Flat bar no prob.
What's your method?
My knowledge comes from me sitting there with my MAPP torch for 4 minutes unable to get a red glow. I got the surface discoloration you referenced but with the lever in my vice and some good whacks with a dead blow, no movement.
Maybe it's the tip on the small torch I have? I don't have a MAP-Pro. Mine works well for 3/8" or so. Anything more and it's hit or miss depending on the cross section. Flat bar no prob.
What's your method?