clay up

1. To create a sculpture made of clay to be used as the model for a mold. A noun or pronoun can be used between "clay" and "up." I was working for a special effects studio for a while, and it was my job to clay up the various creatures and props before they were put into their silicone molds.

2. To cover a portion of a blade, especially its spine, with a clay or clay-like mixture before tempering the blade in a quenching liquid. A noun or pronoun can be used between "clay" and "up." It's important to clay your blade up before you begin the tempering process, or else your blade could end up cracking.