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
--I bent some of the same tube by filling it with sand, bending it
around a 10" pulley that had been turned out inside to 3/8"
radius--Pulling it around with the inner race of a big ball brg that had
used 3/4" balls--this was pressed onto a smaller brg which was bolted to
a bar that pivoted on the center support of the pulley. BUT--
that's a 5" radius & you want 3"---might do it though..send ya a pic if
your interested. wass biplane at tds dot net