It depends on how thick your copper is, and what kind of hammer
blows you give. Also how long the strip is, as if the proportions are
too blunt you will not get much curvature. Long narrow, elegant
proportions are important for best results.
If you forge heartily you should get some movement.
This piece is about 2 feet high, out of 20 guage
And this one is about 2 1'2 feet across out of 24g.
For best results on a Rueger fold:
Keep the hammer at right angles to the fold edge (the handle is
parallel to the fold edge when forging) The blow should cover one
half the distance across the folded sheet (halfway from fold edge to
The mark of the blow should be a single mark, a single blow rather
than a colletion of little pecks. You may not be able to do this on
this size, instead try and get the marks as long as you can.
Stay just inside the fold edge with the hammer blows. (use a
synclastic forging hammer peen).