Suggestions for a thin consistency glue/cement

Hi there.  This is maybe a little off topic....

I have designed a set of chess pieces in a 3D CAD system.  I left a pocket in the base of the pieces to add weight.  My idea is to add steel shot (or lead shot if I can find any) into the cavity then pour a glue/cement into the cavity containing the shot to seal them inplace. 

My question is: What is there in the way of cement that is of a thin consistencey which will flow into and around the shot? I have used two part epoxy in other applications, but that is more like honey and a pretty short pot life. I'd really like a thinner product like a medium weight oil or even water.  I will use some type of ABS plastic when printed so the cement should not damage, soften or deform the base. 

Suggestions?

Larry