Thru Dec 24th: Free set of clamping cauls with qualifying order. (Max one free set per shipping order.)  See the Home Page for details.
 
Non-Stick Clamping Cauls for Resin Casting (set of 10)
These are various-sized blocks of HDPE or UHMW to use as hold-down clamps.  Place them on top of objects you want to clamp or weight down to prevent floating in the mold.  The blocks protect your clamps from the resin, and they do not harm the surface below.    They can be stacked, if needed, to apply pressure where the clamp can't reach. 
The package contains a variety of sizes, including one long, one larger, and 4 smaller random size blocks.  The edges are softened for easy handling.