Bending T6 aluminum

[inventing_man]

Hi guys
I'm using 1 1/2 inch X ,065 wall 6061 T6 on a project. The bends would be formed on a 1 foot radius die sweeping the tube to about 120 degrees . A second piece will be on a 16 inch die and bending 180 degrees.
I read somewhere that to successfully cold bend T6 , a rule of thumb is not to bend under 3 1/2 times its dia. That would be a 4 .5 radius.
So would This cold bending using large radius dies, yield good results with out having to do a lot of heat treating and stuff ? The tubes can ovalize some , that would be acceptable . I'm going to build a roller follower bender with hard wood dies.

[ancient kayaker]

I've never bent Al tubing that tight. Bends in Al furniture use a technique where the tubing face on the inside of the bend is changed from convex to concave. There's some good data at http://www.finishing.com/251/52.shtml

A spring inserted inside the tubing that's a reasonably good fit will help prevent kinking: tie a heavy cord to it to retrieve it. Another trick is to fill it with wax.

[Typhoon]

I can't speak for the diameter you are going to use, but I used to bend anodised 25mm, 2mm wall T6 aluminium tube to 150mm radius all the time. No crushing of inside of the bends, but some fine crazing of the anodising on the inside of the bends. The bends were all to 90 degrees or there abouts.
We used a simple nylon block which the tube bent around, forced by a lever with a nylon roller on it. Both pieces shaped to the same profile of the tubing.
I think you will be O.K with the dimensions you quote.
Aluminium, especially tempered aluminium, is very springy, make sure your bending rig will go about 20 degrees PAST your bend angle, or the tube will spring back to a lesser angle than what you are after.

Regards, Andrew.