Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Plastic molding kits (often involving silicone for mold-making and resin for casting durable plastic-like parts) are great for DIY projects like custom figurines, prototypes, or accessories. These kits typically include silicone rubber, resin, hardeners, and release agents. The process involves two main phases: creating the mold and casting the plastic.

Phase 1: Making the Silicone Mold

This creates a reusable negative of your original object (e.g., a clay sculpture or 3D-printed model).

1.Prepare Your Original Model: Clean and dry your object. If it's fragile, support it with clay or foam to prevent distortion. Place it on a flat base (like a plastic sheet) to build around.

2.Build a Mold Box: Create a containment box around your model using cardboard, foam board, or Lego bricks sealed with hot glue or clay. The box should be at least 1/2 inch (1 cm) taller and wider than your model on all sides to allow for silicone thickness. Seal any gaps to prevent leaks.

3.Mix the Silicone: Measure equal parts of Part A (base) and Part B (hardener) as per your kit's ratios—often 1:1 by volume. Stir thoroughly for 2-3 minutes in a clean container to avoid air bubbles. Work quickly, as silicone sets in 5-20 minutes.

4.Pour the Silicone: Slowly pour the mixture over the model from a height of 6-12 inches to minimize bubbles. Tap the box gently to release trapped air. For complex shapes, use a vacuum chamber if available, or let it sit for 5 minutes before pouring.

5.Cure the Mold: Let it set undisturbed for 4-24 hours (check kit specs). It will feel firm and rubbery when ready.

6.Demold the Original: Carefully cut or peel away the box, then flex the silicone to release the model. If it's a two-part mold (for undercut shapes), align and seal the halves with clay before pouring the second side.

Phase 2: Casting the Plastic Resin

Now pour the resin into your mold to create the plastic part.

1.Prepare the Mold: Spray or brush the inside with a mold release agent (included in most kits) to ease demolding. Secure the mold halves with rubber bands if needed.

2.Mix the Resin: In separate cups, measure Part A (resin) and Part B (hardener) per the kit's ratio (e.g., 1:1 or 2:1). Pour the hardener into the resin and stir slowly for 2-3 minutes. Avoid whipping in air—scrape sides and bottom well.

3.Pour the Resin: Fill the mold from one corner, letting it flow naturally to reduce bubbles. Overfill slightly to account for shrinkage. Tap or vibrate the mold to release air pockets.

4.Cure the Casting: Place in a warm (70-80°F/21-27°C), dust-free spot for 1-24 hours until hard (time varies by resin type—clear resins take longer). Avoid direct sunlight to prevent yellowing.

5.Demold and Finish: Flex the mold to pop out the casting. Trim flash (excess material) with scissors or sandpaper. For multi-part molds, repeat pours as needed.