Dennis Fetters wrote:
Morgans wrote:
"J.Kahn" wrote in message
.. .

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?



Fill the tube with water and freeze it. Bend it with the ice inside,
this will help keep it from collapsing. It's better than trying to use
sand and cheaper than low temperature metals.


I'll experiment with that. Thanks. Doesn't the ice tend to crumble at
the bend and loose its ability to support the tube?

What about welding caps on the ends of the raw tube, one cap with a
treaded hole to take a plug, then filling with water that's had all the
air bubbles removed and plugging?

John