On Sat, 29 Sep 2007 22:41:59 -0700, Bruce L. Bergman
wrote:

On Sat, 29 Sep 2007 19:58:11 GMT, John Doe
wrote:

Is there an easy way to bend aluminum flat bar? Like a device, either
store-bought or homemade? Something other than a simple vice.

Yes, there are many ways to use bending fixtures on bar stock to
bend it at any radius you desire - if you Google around someplace like
Harbor Freight Tools you'll find several.

But if you don't heat treat and anneal the aluminum bar stock to
"dead soft" condition first before you try bending it I can guarantee
failure,

No. As long as you control the bend radius, any of the wrought alloys
are bendable without annealing. The minimum radius depends on the
specific alloy, temper, and thickness.

because Aluminum will fatigue and crack at the bend.

Fatigue is a result of cyclical stress, not a single event.

Sometimes with a sharp bend you have to anneal it, bend part way,
anneal it again, then finish the bend.

There may be some exotic aluminum alloy that strain hardens that
quickly, but I've never run into it.


With Aluminum there is very little difference between the heat
needed to anneal and to melt. You'll end up with some "Oopsies" and a
puddle of Aluminum on the floor where you lingered with the torch just
a little bit too long...

If it is necessary to anneal, the temp should be around 650F; the
melting point of common aluminum alloys is in the range 900-1100F. See
the post by Bill Marrs for one trick for annealing. (As he implies,
we're not talking about a true anneal, but reducing the temper enough
to make relatively sharp bends.)

--
Ned Simmons