mjr6550
Aluminum
- Joined
- Oct 7, 2012
- Location
- Lansdale, PA
I decided to try sand bending some DOM tubing as a learning exercise for a future project. The tubing is 5/8" diameter, 0.120" wall thickness. I needed an inside radius of about 1/4" (if possible).
I made some wood plugs to cap the tubing, packed tight with dry sand, clamped the tubing in a vice against a piece of 1/2" diameter steel rod. I heated the tubing with an OA torch and bent away. The results were poor. I'm pretty sure I know why, but would like any feedback anyone can offer. First problem is that I was using a tinted face shield and working outside. I think I was supposed to heat to dull red. Being the the tubing is small, I got to orange pretty quickly (did not see dull red). Second problem is that with the tubing in the vice horizontally I think I heated the crap out of one side and did not heat the other side quick enough. The photos show significant distortion at one side of the outside of the bend and cracking at the other side.
I would appreciate any general input of heating methods. BTW, I was using a rather large cutting nozzle (don't recall the size, but probably rated to cut 1/2" steel-I need to buy a rosebud). I was using what I think was a neutral flame (maybe even a bit carburizing? and not using extra oxygen.
I made some wood plugs to cap the tubing, packed tight with dry sand, clamped the tubing in a vice against a piece of 1/2" diameter steel rod. I heated the tubing with an OA torch and bent away. The results were poor. I'm pretty sure I know why, but would like any feedback anyone can offer. First problem is that I was using a tinted face shield and working outside. I think I was supposed to heat to dull red. Being the the tubing is small, I got to orange pretty quickly (did not see dull red). Second problem is that with the tubing in the vice horizontally I think I heated the crap out of one side and did not heat the other side quick enough. The photos show significant distortion at one side of the outside of the bend and cracking at the other side.
I would appreciate any general input of heating methods. BTW, I was using a rather large cutting nozzle (don't recall the size, but probably rated to cut 1/2" steel-I need to buy a rosebud). I was using what I think was a neutral flame (maybe even a bit carburizing? and not using extra oxygen.