You can buy flexible styrofoam tubes for kids toys
ropes etc.in several diameters. Wal Mart and most
swimming pool suppliers sell them. They have a hole in
the center for a rope or whatever. Put some copper
tubing in the center hole. force it into whatever
contours you need, the copper tube will keep the
shape. Slip the composite tube over the outside wet it
out. When it cures, dissolve the foam and the copper
can be pulled out. Most important, let me know if it
works. I need to do it too.
                              John