Hard weights for BP?

So here's my issue...

I dive in a local aquarium, and they ban shot weights. Potential risk of leakage, fish ingesting shots, etc. So I currently use a loaner weight belt and hard weights.

My query? Where can I find weights or molds to bolt on to the BP? I'm familiar with cam-band pockets, but with the hypersalinity and shallow depth, we're talking ~24lbs of lead. I'm currently looking at melting down my two rope weights, and using a wax/sand mold.

TIA,
Mike

**edit** For clarification, wax form to shape the sand mold. And yes, the sand would be dry.