I'm bending L stock made of aluminum for a bracket. Should I be heating the aluminum before bending ? The first piece formed a crack after bending.

It's the thin stuff sold at Home Depot--

from my experience and the mechanical guys I was working with on robotics...the home depot stock is not always bendable...its the wrong type of aluminum...there are loads of types.

I have used a torch...it does not melt till 1200 degrees, but to much heat does make it funky.

I heat it, but I do a heat, then bend a little...then heat..then bend...

Rich

It's hardend. Most L stock is an extrusion. Never bent extrusion in the aircraft industry. FAA doesn't like it cause it cracks. You can try a shrinker stretcher. Heat will make it loose its temper (hardness). If that doesn't matter torch away. Aluminum turns shiny a split second before it melts.

Thanks for the heads up. I have a plan B that will not require bending.

I have 6063 O (bendable) aluminum round tube. I use for applied grab rail on my railing. It's 1.9" OD. Let me know if you need any.
DIYRailing.com

Take an oxy acetalene torch, light the acetylene only apply some of the soot to the aluminum stock in the location of the bend on both sides. The add the oxygen to make a neutral flame. Use the flame to remove the soot from the aluminum. When you have carefully removed the soot you will have expanded the molecules and softened the metal.