How To Cast Concrete Molds
•Pourable Mold Rubber
Step 1 – Seal Item to Be Cast
Using sealing agent, cover item to be cast with two layers of agent. Let each layer dry for at least 15 minutes between coats.
Step 2 – Seal Leak-Proof Container
Coat inside of leak-proof container with sealing agent. You can use a plastic container or a cardboard container.
Step 3 – Apply Release Agent
Using a release agent that works on latex and polysulfate, apply the release agent to both the container and the item to be cast.
Step 4 – Mix Pourable Rubber
Pourable mold rubber usually consists of a powder and a liquid agent. Using a disposable container, mix the two ingredients together.
Step 5 – Make Rubber Form
Pour a few inches of the rubber on the inside of the leak-proof container. Wait a few minutes and let the rubber begin to form a slightly solid skin.
Press the item to be cast into the rubber but do not let it go all the way to the bottom of the container.
Pour the rest of the rubber over the item and cover it completely.
Set aside to dry for at least 24 hours.
Step 6 – Release Mold
When rubber is dry, slide it out of the container.
Use razor blade to carefully cut the mold in half to create two parts.
Remove the cast item from between the two halves.
Step 7 – Create Bore Hole
Replace the two halves of the mold together and replace them in the original container that held the rubber.
Using the power drill with a wide gauge drill bit, drill a 1 inch wide hole down the center of the mold until you reach the hollow core of the mold.
If you want to then use your mold to create concrete items, here are the instructions:
Step 1 – Apply Releasing Agent
Apply concrete releasing agent to inside of rubber mold halves.
Step 2 – Replace Mold
Replace two halves back together and reinsert into the mold container.
Step 3 – Pour Cement
Mix cement. Pour cement into the mold through the bore hole in the top of the mold. As you pour the cement into the mold, tap and shake it to release any air pockets or bubbles up to the surface of the mold.
Set aside and let cement dry for a minimum of 24 hours.
Step 4 – Release Concrete
Pull the mold out of the container and carefully peel the two halves apart.
Use steel file to smooth any excess concrete that may have seeped between the two mold halves and created a jagged seam on your concrete figure.
Making a mold for concrete figures and then using that mold is a relatively simple and easy project.