"Nige" wrote in message
...

I need to bend some 22mm copper pipe into quite a wide radius curve -
is it possible to use conventional pipe benders to do this (the type
with long handles)?

It's just that from looking at them, they appear to have a fixed radius
former - or is there a way of increasing the radius of the curve you
make?

Above all, I need to produce smooth curves - is there a better way of
doing it?

Any advice would be appreciated...

Cap up one end, fill with fine sand, cap the other end. Bend over suitable
structure to make the curve. This could be you knee or two metal rollers.
First anneal it. Where the curve is to be heat the copper to cherry red
then quench in water. This makes it more pliable. You will need a
substantial blow lamp to anneal it. You could try it cold first, it may
work. When making the bend, do not make sharp pulls, Gentlly move up and
down the bend pulling a small amount at a time.