You can use your imagination when dealing with epoxy resin, create any shape you can think of. You can even make shapes and molds of your own, there is no limit to what you can do. The problem comes when you have to release your cured resin from the mold. For this, in many cases, you will need a resin mold release agent. Read on to find out more about the pros and cons of mold release agents and the various ways in which you can use it, especially for use on silicone molds.
What are Mold Release Agents?
A mold release agent is a chemical that prevents certain materials from adhering to each other. Not adding a release agent will cause these materials to bond, which then produces more problems in cleaning up and creating a perfect casting.
Do you use epoxy resin and molds regularly? You will then understand the need for an epoxy release agent. Always use an epoxy release agent in your molds, as you do not want your epoxy resin to stick to your mold. Not only do you use the resin mold release agent on small castings, but on larger projects as well. For example, embedding epoxy resin into the wood, or other types of materials.
If you do decide to do your own molds, whether its glass fiber mats or epoxy resin, remember to apply an appropriate mold release agent onto the negative mold form. However, if you do not use the release agent, the created mold won’t be able to come free, and all your work would have been for nothing.
The epoxy release agent creates a barrier between the mold and the resin, preventing the resin from sticking to the mold. If the resin does stick, it will damage the mold and more than likely you will not be able to use the mold again.
Epoxy release agents can be used for:
- Polyester Resin
- Polyurethane Resin (occasionally)
When it comes to materials like wood, there is not a suitable epoxy release agent. This is because wood and some other materials like plaster or foam are porous, they will absorb the release agent and it will then be ineffective. So, in future, if we mention a wood epoxy release agent, it means that the wood has been sealed beforehand.
Mold Release Spray
When using an epoxy mold release agent, there are two forms of application, a release wax and release spray. Which one you select will depend on what you want to do. A mold release spray works well on more intricate and smaller molds because it is easily sprayed on. The wax release agent needs to be rubbed on to surfaces.
The mold release spray functions as a blend of wax substances and aerosol. The aerosol delivers the barrier wax substance onto the mold. The wax substance will remain while the aerosol particles evaporate.
Best use for Mold Release Spray
The mold release spray is excellent to use on molds that have detailed surfaces and lots of corners. The spray method can get into the corners and disperses the release agent evenly over an uneven surface. Sometimes, the release agent can remain on your resin casting. To get an even surface, you can polish your resin epoxy casting or try some soap and water. In most cases, this is not necessary.
Applying the Mold Release Spray
The surface you are going to spray must be clean and free from any greasy marks or dirt. The same is valid for all mold release agents including the wax and PVA release agent. If any residue is left on the surface of your mold before casting, it will stop the release agent from sticking to the mold. The release agent will simply glide over the surface without fulfilling its purpose. Once your casting has cured, it will demold with difficulty and this can damage the mold.
Once you have carefully cleaned the surface, shake your mold release spray can. Spray over your mold surface, making sure it is only a thin layer. Spray every angle and when spraying, make sure to hold the can about 20-30 cm away from the mold. Leave for about 2-3 minutes. Then, if needed, polish the layer with a soft cloth.
When it comes to new molds, you should apply at least three to several layers following the above process. Allow to flash off (the required time you need to wait before applying another coat) overnight after each layer has been sprayed.