The Stovebolt Site Forums The Shop Area Paint and Body Shop Oxy propane torch settings

I have a propane gas axe and want to try to use it shrink some pretty significant dents on my hood. If I succeed, yay! If not, I think I can find a good hood fairly easily in these parts.
For this, what do you recommend for pressure and flow using a brazing tip? I haven’t removed the cutting tip yet.

I can't say for sure what you have, not being familiar with oxy/propane torches. But I would use the smallest brazing tip you have and work in small spots. I've used a '0' torch tip with oxy/acetylene for a little shrinking.

I'd say this is a question for Robert (MP&C), him being the expert sheet metal guy. He can probably give you some tips so you don't totally destroy the hood.

Might consider using a shrinking disc in lieu of heat. More control...metal properties change quickly with heat. Or maybe hammer and dolly first. Just a thought.

That’s my plan, Apache, but I don’t think I’ll be able to get it dokey with hammer and dolly. It had a pretttymwhack on the front that caused a good crease. The metal has been damaged pretty badly. Not a huge area, but it is significantly dented.

Getting an Oxy-Propane flame adjusted down to a fine enough point to shrink with might be a challenge. An acetyline rig with a #0 tip allows me to heat an area about the size of a dime or smaller red hot, then quickly quench it with a water-soaked rag. Shrinking is mostly used to correct "oil canning" where the dented metal has been stretched beyond its natural "memory" elasticity. Rough out and "metal finish" most of the dent out with a hammer and dolly, then shrink the places that refuse to go back to their original contour. Resist the urge to heat before you do the necessary hammer and dolly work to achieve a contour that's very close to original.
Jerry

I would double check the wack in the front that you mentioned. You may have to pull the wack on the front a bit to get that dent out. Once your sure the front edge is straight then you can think about shrinking.

I have used a oxyacetylene torch with the smallest top to shrink with success. Like HRL said, heat a dime size spot cherry red, then I take a hammer and lightly tap the area around the spot to massage the excess metal into the spot then quench. I then cool the panel before heating another spot if required. It may require several spots to eliminate the excess metal.

It’s fairly easy once you get the process and practice it a few times. You’ve got the talent, I’ve seen your work.