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bending aluminum

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Posted by Jeff on December 10, 2007, 8:45 pm
 
   I have some warm weather here and want to finish my solar water
collectors.

   I have .01" aluminum flashing and need to bend some channels to go
around the 1/2" copper risers. I have a jig of sorts where I'm pushing
the 1/2" copper (5/8" OD) pipe into a slot the same width. This forms a
"U" but the "U" springs back out quite a  bit when it is withdrawn  from
the channel.

   Any ideas on forming a more closely fitting channel in the aluminum?

   Jeff

Posted by Anthony Matonak on December 11, 2007, 3:58 am
 
Jeff wrote:

The only thing I can think of is to figure out how much it "springs out"
and find some pipe of that smaller diameter to form the slots. When the
flashing springs out it'll be the right size.

You might also try heating the aluminum while it's in the jig to remove
the temper. I'm not sure how well that works or how hot you would need
to get it but if your fire insurance is paid up it might be worth a try.

You could always just cheat. Cut a strip of flashing wider than the
copper pipe and screw or rivet it on top to hold the pipe in place or
make the back of your collector out of wood with slots cut in it and
just never take it out of the "jig".

Anthony

Posted by Jeff on December 11, 2007, 11:49 am
 Anthony Matonak wrote:

The trouble is that you can only wrap the flashing around half way (an
open "U" instead of a "C"). No matter what the initial size,  then it
will alway spring back.

   I think this may need to be a two step process. One to bend this into
a "U", but a U that has sprung (when I rivet this, I want to minimize
the shear on the rivets) and then a following bend around a smaller
diameter. I'm unsure how to accomplish that second closing bend.

   I think I'll try pushing it closed and have a rough idea on that.

   Jeff




Posted by nicksanspam on December 11, 2007, 12:33 pm
 Jeff wrote:


Some aluminums are springier than others. Amerimax coil stock worked fine
for me with almost no springback, eg Lowes 2'x50'x0.018" brown and white
coil, sku 17376, Napco (704) 473-7868) or Home Depot's sku 125467, for
Amerimax (717) 299 3711 p/n 69124. A different unpainted stock sprang back
big time.

Nick


Posted by gary on December 11, 2007, 4:11 pm
 
Hi Jeff,
The jig shown down the page a ways at this link:
http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/House.htm
Has the top of the pieces that form the groove tapered down a bit so
that when you take it out of the jig the two fins have a bit of down
slope.  When you staple the fin to the backing board the fins are
straightened out, and this pinches the tube a bit tighter, and wraps
it a little more than a U channel would.  I'm not saying its ideal,
but I think its a touch better than just a U channel.
It does  require a backing board behind the fins, which you may not
want to do.

Gary


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