A standard hydraulic tubing bender for 3/4 OD tubing has a 3" radius
to tube centerline and says the minimum wall without flattening is
0.049 for "high strength" aluminum, or any for soft aluminum. If you
have a piece to try, head to your local hydraulic shop and ask them to
try.

With inner support, there is lots more capability, and as close as
this is, the spring will probably be enough.

On Mon, 05 Mar 2007 11:01:37 -0500, "J.Kahn"
wrote:

I need to make bends of about 30 degrees in a 3/4 x .049 longeron tube,
with a tight bend radius, no more than 3 inches. Can I do the bend hot
without wrinkling the tube by free bending or do I need a supporting die
of some kind? Anybody have any specific techniques?

John