In this video I walk you through the steps to make a silicone mold. This particular mold will make 4 single pen blanks. I wanted to make a single blank silicone mold so that I could insert embedments into the mold and have it hold them in place while casting. With this design, I can cast embedments in the blanks in precise locations to make the best looking hybrid pen blanks.
Silicone is a wonderful mold material for resin casting, and it’s really not that difficult to use. It’s very similar to regular old resin casting, just mix the two parts up thoroughly and pour it in your master mold. I used MDF for the blank masters, corrugated plastic for the base of the master, and foam core for the walls. Everything was hot glued down, and easy to set up.
The silicone was degassed in a vacuum chamber before pouring, which is a crucial step if you plan to use the mold under pressure. If there are air bubbles in the silicone, they will collapse and could deform the mold in the pressure pot.
I used Alumilite’s High Strength 1 silicone to make the mold, and I was really happy with how easy the product is to work with. Some silicone brands are extremely thick and it’s a chore to get it mixed up with the hardener, but the High Strength 1 was very thin and easy to stir up. Big thank you to Alumilite for sending me the silicone to test out for this video.
The overall mold dimensions are 7.5″ x 7.5″ x 2″, and each slot’s dimensions are 1.5″ deep x 1″ wide x 5.5″ long. It’s probably not necessary to build it as heavy duty as I did, but I wanted to make sure it was sturdy. You could also make the blank size anything you want by adjusting the size of the wood pieces accordingly.