"David Billington" wrote in message
news:4f105d8d$0$2492
I used the large pipe trick but wanted to preserve the surface finish on
some 5mm aluminium so used some 5mm UHMWPE sheet I had around between the
pipe and al. The surface of the PE sheet didn't look to good after forming
but the aluminium hardly showed a mark.

That's a good idea. I've tried cardboard but it rips easily. Plastic sewer
pipe tends to crack. It might be good enough for auto body steel.

jsw