If you’ve ever worked with molds—be it for casting resin, plaster, concrete, wax, or making your own soaps or candles—you know how important it is to get the finished product out of the mold cleanly.  That’s what mold release agents are for. A mold release agent will allow you to remove the item from the mold without sticking, tearing, or changing the shape.

 But what can you use for a rubber mold release agent? Let’s examine some basic and effective options.

What is a Mold Release Agent?

A mold release agent is a lubricant or coating that gets put on the inside surface of a mold before pouring in your casting material. Their job is simple: stop the casting from adhering to the mold. The release agent allows for a cleaner de-molding experience and helps keep your mold in good shape for reuse.

Common Types of Rubber Mold Release Agents

There are several release agents you could use depending on what material you are casting and what type of mold. Below are some of the most popular.

1. Silicone Spray

Silicone spray is a popular choice of rubber mould release agent. It’s easy to use, can be applied by spraying it onto your mould, and works with most materials. It creates a slick surface that deters sticking. Simply spray on a coat, allow it to dry, and it’s ready! Silicone spray works perfectly with resin, rubber, and even some plastics.

2. Petroleum Jelly (Vaseline)

Just apply Vaseline to the mould either with a rag or your fingers. It works great with rubber and latex when casting concrete or plaster. Just don’t overdo it or it might mark up your final piece.

3. Dish Soap and Water

No fancy products here! If you are casting plaster or clay, a mixture of soap and water works well as a release agent. Just brush it on your mould, let it dry a little, and pour. It’s a gentle and inexpensive release agent for one-off jobs or quick projects.

4. Commercial Mould Release Products

These products are specifically designed for use with specific materials. When casting urethane or silicone, it is best to use a commercial rubber mould release agent if the manufacturer recommends using one. These are developed for a clean release without damage to the mould or the cast part.

Final Tips

Always test first. Before you go to the full casting, try the release agent on a small area or a test piece.

Use the right combination. Some materials will not react well with certain release agents. An oil-based release agent may not work well, for instance, with certain resins.

Always use a light coat. An even thin coat is better than a thick greasy coat.

Conclusion

Choosing the right rubber mould release agent can make a significant difference in your casting project. When casting with your first creation that is made out of an everyday item, or a professional-grade spray, all projects are all the same. You want a clean release, perfect projects, and moulds that last longer. Try a few options. You may be surprised!