Elaine I’ve made a few of these out of silver, the trick is to make
sure that the metal strip is very work hardened. The sheet that I buy
(1mm thick) is not annealed after rolling, so is generally up to the
task, and I make the fold in two bends to give extra springyness -
first I fold the metal over a rod with a 1cm diameter, and then clamp
a thinner rod (6 inch nails work well) on the base of this curve and
pushthe money clip down into position. The Complete Metalsmith by
McReight (sp?) also mentions a special silver alloy called Spring
Silver witch is made for this task, but I’ve never felt the need to
use it. Regards Chris Penner