: Your mentioning polyester resin made me think of automotive filler
: putty--it's a pre-thickened polyester resin. Bondo 'n Sand would be a
: perfect hold-making medium. (With little need for the non-boatbuilding
: type to have to learn about thickening resins, etc.)

Hi Shawn,

I wouldn't recommend using Bondo to build handholds. Bondo has very little structural strength and will fail if weight is applied to it. The micro balloons in it are for FILLING purposes only.

You could perhaps use one of the longstrand fiberglass fillers which do have considerable structural strength but they are hard to sand. You could use a mold or use plastic to form them by hand. Attaching them to the wall will be another problem.

Ian