Flattened copper tubing

Flattening the 1" copper tubing will give a flat 1.5" by (guessing) ~0.1"
ribbon.  According to what I've read on the subject, this is a prefered way to
go.  I use tubing "tubularly" only because it is readily available and flat
copper isn't.
The inductance of a spiral coil is a function of the inter-turn spacing; i.e.:
the overall number of turns in a given coil raduis.  So, the more turns you can
pack into that radius, the better!  Flattening tubing brings another benefit,
too: the edges are automatically nicely rounded which means there is less chance
of corona; which means you can have an even closer inter-turn spacing; which
means more inductance!
I discussed the possibility of flattening copper tubing with my brother (metal
is his profession) and he offered this advice:  you must find a way to wind the
coil as you flatten the tubing because, as has been pointed out by otherst, the
copper will be much less "forgiving" after being flattened - it will easily kink
if bent.  The trick is to feed the tubing into the rollers in the same plane as
it was packed - this is no easy task, I assure you!
Best of luck,
J. D. Wiggins