Casting pewter can seem like a challenging process, but with the right tools and materials, it's completely doable, even for beginners. David Boardman, a passionate creator, shared a detailed tutorial on Facebook about how he successfully cast a pewter hand model using Siraya Tech Fast Navy Grey Resin for 3D printing and Siraya Tech Defiant 25 Silicone for molding. Here's a step-by-step guide based on his process.
Step 1: Preparing the 3D Print
Start with a clean and fully cured 3D print made from Siraya Tech Fast Navy Grey Resin.
To clean and cure the print:
- Cleaning the Model: Use methyl hydrate, 90%+ isopropyl alcohol (IPA), or ethanol to clean the print.
- Rinse: Rinse the model in hot soapy water, then follow up with a cold water rinse.
- UV Curing: Submerge the model in a container of water and cure it under UV light for at least 30 minutes. Cure in water for 30 minutes to ensure the resin does not inhibit the curing of the silicone.
- Drying: Ensure the model is completely dry before proceeding.
Step 2: Setting Up the Silicone Mold
Once your 3D print is ready, it's time to create the mold using Siraya Tech Defiant 25 Silicone. Here's how:
- Attach a Sprue: Add a sprue to the model, which will serve as the entry point for pouring the pewter. Use double-sided tape to stick the sprue to the center of a small Dixie cup, ensuring there's about ½ inch of space around the model.
- Mixing the Silicone: Measure equal parts (100g each) of Part A and Part B of the silicone. Mix thoroughly in a clean container for about 3 minutes, scraping the sides and bottom to ensure a uniform mixture.
- De-Gassing the Silicone: Use a vacuum chamber to remove any air bubbles from the silicone for 2-3 minutes.
- Pouring the Silicone: Slowly pour the silicone down the side of the cup rather than directly onto the model to avoid trapping air bubbles.
- Curing: Let the silicone cure for 4-6 hours at room temperature (around 25°C).
Step 3: Finalizing the Mold
After the silicone has cured, it’s time to release the model and prepare the mold for casting:
- Remove the Silicone: Carefully remove the cured silicone from the cup.
- Cutting the Mold: Make three cuts down the side of the silicone to release the model. Start cutting where the pewter will be poured (the point where the model was attached).
- Vent Holes: Drill small 2mm holes into the silicone, close to the top of the mold, to vent air while pouring the pewter.
- Dusting the Mold: Lightly dust the inside of the mold with baby powder or talc using a small paintbrush to help the pewter flow and fill the details.
- Securing the Mold: Use elastic bands to keep the cuts tightly together during the pewter casting process.
Step 4: Melting and Pouring the Pewter
Now that your mold is ready, it's time to melt and pour the pewter:
- Melting the Pewter: Use an electric melting pot, such as the Hot Pot 2, to melt the pewter. It typically takes around 15 minutes to melt, and you should aim to maintain the temperature around 400°F. Use a thermometer to monitor the temperature.
- Pouring the Pewter: Pour the molten pewter slowly into the mold to minimize air bubbles and ensure all details are filled.
- Cooling: Allow the pewter to cool and solidify for 10-15 minutes.
Step 5: Finishing the Pewter Casting
After the pewter has cooled:
- Removing the Casting: Carefully open the silicone mold and gently remove the pewter casting.
- Finishing Touches: Trim any excess material (the sprue) and smooth the casting as desired.
To see David's original post, visit his Facebook page.
Happy crafting!