Low-melting-point alloy Casting: DIY Metal Dice Mold (Easy)

Cast real metal dice safely at home using just hot water!

This project uses a 3D printed PETG mold to cast ultra-low melting point alloys (melting point < 80°C / 176°F) without needing a furnace or open flame.

Unlike traditional casting, this method uses a hot water bath to melt the metal. Since boiling water never exceeds 100°C, you cannot accidentally overheat the metal and destroy your PETG mold.

Key Features

• Real Weight: Creates solid metal dice, not plastic.

• Non-Toxic & Safe: Designed for Lead-Free alloys melted in hot water.

• High Detail: Optimized for 0.1mm layer height printing.

⚠ Required Materials

1. Low Melting Point Alloy(Lead-Free & Cadmium-Free):

   • Quantity: Approx. 50g - 60g per dice.

   • Melting Point: Must be below 100°C (e.g., 70°C - 80°C).

   • Reference: I used a low-melting alloy from a Japanese supplier (Link below), but any generic "Field's Metal" or "Low Temp Casting Alloy" works.

   • Product Link (Reference): https://www.zairyo-ya.com/?pid=178248785

2. PTFE-based Lubricant: (Spray or liquid) - Essential for release.

3. Rubber Bands: To secure the mold halves together.

4. Filament:PETG, ABS or ASA. PLA is NOT recommended as it will warp.

Print Settings (Crucial for Success)

To ensure the mold withstands the heat and produces a smooth finish:

• Material: PETG (Required).

• Layer Height: 0.1mm (Highly recommended to minimize layer lines on the casted metal).

• Infill: 40% or higher (Provides structural integrity and heat absorption).

• Perimeters (Walls): 3 loops or more (Ensures the mold is watertight and durable).

• Supports: No supports required for the mold interior.

Casting Instructions (The Hot Water Method)

1. Apply Release Agent:

   Apply a thin, even coat of PTFE-based lubricant to the inside of the mold parts. This prevents the metal from sticking to the PETG.

2. Assemble & Secure:

   Close the mold parts together and wrap rubber bands tightly around them.

   • Tip: Ensure the mold is tightly closed to prevent molten metal from leaking out.

3. Melt the Alloy:

   Place your Lead-Free alloy in a small metal cup. Submerge it in a bowl of hot water (approx. 90-100°C). The metal will liquify within minutes.

4. Pour:

   Remove the container from the water and dry it off. Pour the liquid metal slowly into the mold.

   • Safety: Wear heat-resistant gloves (Rubber or Silicone)! The metal and water are hot enough to cause burns.

5. Cool Completely (CRITICAL):
   Let the mold cool down completely. DO NOT open the mold while it is still warm.
   Pour the liquid metal slowly into the mold.

   • ⚠ DANGER: If you open the mold before the metal has fully solidified, molten metal can splash out and cause severe burns. Be patient.

6. Demold & Finish:

   Remove the rubber bands and release the die. Cut off the sprue and trim any flash. Sand or polish the faces if necessary.