Mastering the Art of Silicone Mold Making: A Step-by-Step Guide

1. Measure Components

Weighing silicone accurately is the key to a successful mold. Start by measuring the base material first in a clean, dry mixing bucket. Utilize a digital scale for precise measurements.

2. Mix Thoroughly

Combine the activator with the base material and stir rigorously. Use a paint stick or a paddle drill bit, ensuring thorough mixing that reaches the sides and bottom of the container.

3. Vacuum Chamber

Place the mixed silicone in a vacuum chamber to eliminate air bubbles. The material will expand and collapse as air is drawn out. Continue degassing for 5 minutes, slowly releasing the pressure back into the chamber.

4. Pour

Pour the silicone carefully into a corner of the mold box, aiming to fill from the bottom up. Avoid pouring directly onto the master to prevent damage or air entrapment. Fill ¾” over the master for optimal results.

5. Allow to Cure

Let the silicone cure overnight or as per the Technical Data Sheet (TDS) instructions. To minimize air bubbles, consider using a vacuum chamber for 5-10 minutes or placing the mold in a pressure tank at 40-60 psi during the curing process.

6. De-mold

Disassemble the mold box and gently remove the silicone mold. After carefully taking the master part out, consider a slight post cure in an oven at 120 degrees F for one hour before casting the first part. Some molds may require cutting along a parting line using a sharp xacto knife.

7. Finished Product

Clean any flash, blow off the mold’s surface with compressed air, and reassemble the mold using packing tape, rubber bands, or screws. Ensure not to over-compress the mold sides. Your mold is now ready for polyurethane casting, marking the completion of a meticulous silicone mold-making process.