I'd recommend mixing up a portland cement-based mixture, rather than using your expensive epoxy....but if you really want to get rid of epoxy, then just try straight silica sand.

I'd go concrete--use about 1 part cement to 2 parts sand, and use a very little amount of water (mix like hell and keep it as dry as possible for more strength) more water=less strength. Once the concrete holds reach initial strength--overnight to 2 days, put them in a bucket of water for a week to cure. Bolt 'em up and enjoy!

Shawn

I actually made some holds with regular 3/4" aggregate concrete--never got around to putting them on a wall, though. I just put a washer in the middle of each hold, and poked a hole down through it. The washer should spread some of the stress from the tightened bolt. All I have to do is go through the washer with lag screws or allen-headed bolts into t-nuts in the plywood.

: 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)