Grant Erwin wrote:
I scrounged a piece of 1/2" copper tubing 100' long
back in the '80s but have never had the nerve to try to bend a neat
spiral. It's awful easy to kink tubing during bending. Lots of guys tell
you to do this but no one to my knowledge has yet actually described how,
ideally with pictures.

I have not formed 1/2" copper into coils but have done lots of 1/4" and
3/8" stainless (316L) tubing coils. The way I did them is easiest with
two people. Find a parking lot with a 10" or 12" diameter steel pipe
sticking up out of the asphalt like a parking barrier. It will probably
need to be 4 or 5 feet tall. Get your partner in crime to hold one end
of the tubing against the pipe at the bottom with the stub length you
want outside of the coil sticking out. You walk around the pipe while
pulling the tubing tightly against the pipe. As long as you keep the
tube tight against the pipe while you walk, it will not kink. If you let
the tension off the tube, it will kink instead of forming neatly around
the pipe. Refrigeration copper is pretty soft, so I think the same trick
would work.

Sorry, no pictures, I did all these in or around a semiconductor fab
that prohibited cameras.

Bob