How to Make a Bullet Mold

You can make a mold to cast a bullet using urethane RTV molding rubber and a few items found at a craft store. Making a mold will allow you to make as many duplicates of a bullet as you wish. Since one-part molds are used for flat objects, a two-part mold is best for this project.

Things You'll Need

• Bullet
• 5 rectangular acrylic pieces
• Glue gun
• Non-hardening clay
• Uncooked rice
• Liquid measuring cup
• Urethane RTV molding rubber
• Mold-release spray
• Knife
• 2 pieces of wood (same dimensions as the mold)
• 4 wide rubber bands

Instructions

1. Create a container out of rectangular-shaped acrylic pieces. Put the bullet on its side on a flat surface and arrange four acrylic pieces in a rectangular shape around the bullet. Put a fifth acrylic piece underneath the bullet. Make sure the acrylic box fits tightly around the bullet with only about an inch space left around it.

2. Glue the acrylic pieces together with a hot glue gun. Allow it to dry.

3. Place non-hardening clay into the bottom of the container and spread it out deeply enough to cover up to the middle of the bullet (after it is pushed into the clay later). Make sure there are no bubbles in the clay.

4. Push the bullet into the clay. Make sure it does not touch the bottom of the container.

5. Punch six half-inch deep holes into the clay around the bullet using the eraser end of a pencil.

6. Pour uncooked rice into the acrylic container until it covers the bullet completely, plus a little extra. Pour the rice out of the mold into a measuring cup. Take note of the number of ounces and then mix this same amount of urethane RTV molding rubber according to the manufacturer's directions.

7. Spray the inside of the mold container (clay, acrylic and bullet) with mold-release spray.

8. Pour the urethane RTV molding rubber very slowly into the corner of the mold. Allow to dry for 24 hours.

9. Pry off the bottom acrylic piece with a knife and flip the mold container over. Remove the clay with a knife. Repeat step 7.

10. Mix the same amount of urethane as before and pour it into the corner of the container, allowing it to dry for 24 hours.

11. Pry off the sides of the container using a knife. Separate the two parts of the rubber mold and remove the bullet.

12. Sandwich the rubber mold between two pieces of wood and fasten it together with a few rubber bands.

13. Pour the casting material of your choice into the mold to replicate the bullet.

Tips & Warnings

• Don't pour the rubber onto the object because this could create bubbles that would ruin your mold.

References

• YouTube Video: Two-Part Mold Making
• HP Publish: Making Loading Dies and Bullet Molds