:I've thought of doing the same thing. When I considered using epoxy I was not willing to use that much epoxy for the hand-holds. My solution was to make the hand-holds from wood and then cover them with some kind of coarse cloth (like your shirt, not glass) Seems to me that the cloth will provide the rough texture needed for hand-holds and would also bond the cloth to the wood. I have not tried this yet but would be my first way to go when I do. Hope this helps.

I have a friend who's into rock climbing and is making himself a climbing
: wall in his basement. He has only one 4x8 sheet of plywood on the wall
: with a very few wood blocks for hand-holds, because the purchased holds
: are expensive (~$7 each, and you need quite a few...)

: I have a bit of extra epoxy and was thinking about attempting some holds. Any
: opinions on what would be the best for cheap, bulky filler? The holds
: would be in irregular shapes cast around something like a big hex bolt for
: attaching to the plywood climbing wall. The holds have to be strong enough
: to support a man's weight.

: So should I keep with the standard sawdust? Sand? (it would mimic rock
: nicely)