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

John,

They make special heavy springs which fit inside
tubes to support the inside radius of the bend and
keep it from collapsing when you bend it. Pulling
on the spring causes its outside diameter to get
slightly smaller so that you can get it out of the
bent tube after you're done.

Check at automotive parts stores and Harbor Freight.

Good luck with it,

Don W.