How to Make Plastic Moldings

Make Plastic Prototypes of Matchbox Cars

Creating a plastic molding can be a do-it-yourself project. Manufacturers of plastic prototypes make use of big machines to produce prototypes of different shapes and sizes. If you are only making small prototypes, there is no need to buy the expensive plastic molding gadgets. You can create your own plastic molding in the comfort of your own home using things that are already available at your fingertips using a small amount of effort and time.

Things You'll Need

• Small jar made of plastic (ex: peanut butter or mayonnaise jar)
• Used soda bottle made of plastic
• Plastic wrap
• Duct tape
• 2-gallon empty milk or water plastic containers
• Cutter or exacto knife
• Wooden frame
• Vacuum
• Clamp or laundry wooden clips
• Heated gun or electric plate

Instructions

1. Puncture several holes, 1/4 inch apart, on top of your plastic jar cap. Set aside.

2. Cut a little slit on one side of the body of the plastic jar using a sharp exacto knife or blade. The size of the hole should be enough to fit the tip of a 2-liter plastic soda bottle. Set it aside.

3. Cut the top or mouth opening of the 2-little plastic soda bottle, leaving a small portion from the neck close to the opening. Then, insert this through the slit on the plastic jar you have prepared in Step 2.

4. Wrap the plastic jar with plastic wrap. Wrap around two to three times, making sure to wrap around the areas of the slit where the soda bottle opening was inserted. Ensure that it is air tight by wrapping duct tape over the saran wrap and around the slit opening.

5. Place the punctured lid on the plastic jar (see Step 1) and close it tight. Wrap more duct tape around the sides of the lid.

6. Prepare your plastic to use for molding. You can use empty 2-gallon milk or water plastic containers. Cut the body of the plastic container to reveal a couple of flat square pieces.

7. Use a couple of 2-inch wide framing wood to hold the piece of plastic in place. Place a couple of small clamps or wooden laundry pins to secure them into place.

8. Choose the object that you will create a plastic prototype of, small enough to fit the top of the punctured plastic jar lid. An example would be a matchbox car. Place the piece on top of the punctured lid.

9. Connect your vacuum hose to the mouth opening of the 2-liter soda bottle that you placed on the side of the plastic jar. Turn it on. This will help suck out the air.

10. Hold the plastic medium that you prepared in Steps 6 and 7 on top of an electric plate or use a heated gun to blow on it until it starts to turn soft and gooey. Apply enough heat without melting the plastic too much that it liquefies. Take the heat off once the desired elasticity is reached.

11. Place the softened plastic immediately on top of the object that you will mold. This will take about a few seconds and the air suction would mold the plastic tightly around the object.

12. Turn off the vacuum and let the plastic cool off for about 5 minutes. Remove the plastic molding from the object by gently peeling it off. Cut the excess plastic leaving only the protoype image of the object.

Tips & Warnings

• Create a bigger plastic molding using bigger jars or using empty 10-gallon paint plastic containers.

• Use an oven to soften bigger plastics.

• Do not use gas flames to soften your plastic as the end result will not be as good as the suggested method above. Gas flames can leave dark residues and can cause the plastic to burn in flames.

Resources

• Read this Article in Spanish