In article ,
Chris Bacon writes:
Andrew Gabriel wrote:
One way this
used to be done with very large copper pipes was to fill them with
molten lead under pressure instead of sand, at a suitable temperature.

I want you to tell me more about this, please.

Not sure I have any more info. I got it from an old book on using
copper (which is also where I learned of filling with sand to
bend pipes). There was a photograph of two young factory workers
bending a pipe this way. Next time I'm over at my parents', I'll
dig out the book and see if it says anymore. It's hardly suitable
for 'd-i-y' pipe bending though;-)

--
Andrew Gabriel