Petri Dice | A How To Guide

Petri dice capture a mesmerizing, marbled explosion of color, making each piece uniquely beautiful. In this blog, I'll guide you through the process of casting petri dice using dice blanks and numbered molds, ensuring no cure inhibition occurs.

Working with resin requires patience. It's common to encounter setbacks, even if you follow the instructions perfectly. The key is to persevere and practice. Over time, you'll develop a feel for how your resin behaves in your shop's environment, especially since temperature and humidity play such a significant role.

Materials You'll Need

To get started, you'll need the following tools and materials:

• Dice blanks mold (for creating your base dice)
• Numbered mold (for adding the numbers and finishing the dice)
• High-quality epoxy resin
  • I prefer to use Unicone for the blanks and Liquid Diamonds for the numbered portion.
• Alcohol inks in the colors of your choice
• Pinata White Alcohol Ink (SPECIFICALLY THIS - IT'S IMPORTANT)
• Nitrile gloves, safety goggles & a respirator rated for organic vapors
• Mixing cups, stirring sticks, and a heat gun (a lighter or torch can be used, but a heat gun is highly recommended with petri, as it's easier to ignite these materials)
• Sandpaper and Zona Polishing Papers for finishing

Step 1: Cast the Dice Blanks

1. Prepare your dice blanks mold.
2. Mix your epoxy resin according to the manufacturer's instructions, ensuring precise measurement and thorough stirring to avoid bubbles.
3. Pour resin into each of your dice cavities, filling each about 3/4 full.
4. Allow the resin to "gel" for 15-20 minutes before adding alcohol inks. This prevents the inks from pooling at the bottom and allows for better tendril formation.
5. Add your chosen alcohol inks to the resin, followed by the Pinata White Alcohol Ink. The white ink, being heavier, will drop into the resin, creating the petri effect.
6. You can add multiple layers of ink, but one layer is usually sufficient for dice due to their smaller surface area.
7. Top off with a small amount of resin to help the inks flow. Gently swirl with a toothpick, if desired.
8. Use your heat gun to remove any bubbles.
9. Securely close the mold with the lid and place it in your pressure pot.
10. Allow the resin to cure for the recommended time (usually 24-48 hours) as per the manufacturer's instructions.

Step 2: Transfer to the Numbered Mold

1. Once the blanks are fully cured, remove them from the mold and sand any rough edges.
2. Lightly sand the surface of the blanks where the new resin layer will bond. This improves resin adhesion and prevents contamination.
3. Mix a fresh batch of resin and pour it into the numbered mold, filling each cavity about 3/4 of the way.
4. Dip the blanks in the fresh resin and place them in their corresponding cavities in the numbered mold.
5. Fill any remaining empty spaces in the mold.
6. Allow the resin to sit for at least 5 minutes to allow bubbles to rise.
7. Use your heat gun to remove any bubbles.
8. Securely close the mold with the lid and place it in your pressure pot for the recommended curing time.

Step 3: Demold and Finish Your Dice

1. After the resin has fully cured, carefully demold your dice.
2. Experiment with the waiting time before adding alcohol inks to achieve your desired droppage effect.
3. Feel free to tag me in any of your creations! I love to see what you all create with my molds!
4. For finishing instructions, refer to my blog entry on hand polishing and pottery wheel techniques.