permaculture

[Mark <mpludwig@facstaff.wisc.edu>]

At 08:22 AM 4/10/02 +0100, you wrote:

> Dear Elijah,
>
> My Granddad used to bend copper pipe by filling it with sand and bending it
> over his knee. The sand supports the inner circumference, preventing it
> from kinking (go slowly though!). Thinking about it, a polytunnel would be
> fairly easy to make like this, with the 'ribs' connected by a central
> 'spine' at the top by any of the cheap and easy plumbing connectors
> available.
>
> Thanks for the idea!
>
> Simon.

You will find that copper and aluminium will both be very expensive metals 
to build with compared to steel.  Steel also has much better structural 
characteristics than Cu, especially the softer grades.  The whole trick 
with any bending is to spread out the forces involved and support the pipe 
as with the sand example.  Good luck.
Mark


Mark P. Ludwig
Poultry Research Lab
University of Wisconsin -Madison
608-262-1730 WK
608-846-7125 HM