On Wed, 01 Aug 2007 16:12:45 -0500, Jon Elson wrote:



I've got steel, SS and even copper down just PAT, but aluminum still
drives me crazy. I don't know why. (I have a Lincoln Square-Wave TIG
300, supposed to be a good machine.)

Practice, practice, practice; 5-10x as much as it took to get good at
SS. g

I came up with this technique for folding aluminum without a brake
after learning a similar technique that jewelers use. The grooves in
the 1/8" sheet are cut about 1/16" deep with a 90 degree single flute
countersink. You can see some cracking on the outside of the bends in
the second photo - annealing or a different alloy should take care of
that in cases where it matters.

This probably doesn't help much if you need to install internal ribs,
but it does make nice boxes.

http://www.suscom-maine.net/~nsimmon.../Mailbox00.JPG
http://www.suscom-maine.net/~nsimmon.../Mailbox01.JPG
http://www.suscom-maine.net/~nsimmon.../Mailbox02.JPG

The jewelry technique involves scoring a piece of sheet by hammering a
piece of curved steel wire into the surface of the sheet. You can make
interesting 3D shapes in soft metals very easily this way.

--
Ned Simmons