It is relatively easy to make molds and casts. The problem lies in how to get the mold to release from the model and the cast from the mold. A release agent makes things easy without any tears or deformation.

The standard approach to mold making and casting is to first make a mold of the model using materials like clay, wax or mold rubbers. Once the mold is cured, finished and ready, it is used to make the cast with materials like plaster, resins and casting rubbers.

However, in the mold making and casting process, there is always the risk that the materials may stick to the model or mold and become difficult to separate. This can end up damaging the model/mold, not to mention wasting the money and efforts that went into making the mold/cast. So, the question is how to make a mold or cast without such kind of bonding or mechanical locking between the materials?

What to do?

The trick is to use a good release agent that will allow easy demolding. This is usually a chemical that, when applied on the surface, will prevent certain materials from adhering to each other, thus allowing for perfect molds and casts.

There are different kinds of release agents to suit the type of material being used as well as the surface that it has to be separated from. While some artists prefer regular items, like petroleum jelly, talcum powder, soap, wax, etc., it is always better to opt for specially formulated release agents as they are designed to form a barrier between the surface and material.

At times, the model may have to be sealed prior to applying the release agent to keep the latter from getting absorbed into the model.

It should be noted that while silicone does not stick to anything except itself, seasoned artists still prefer to use a release agent as this will increase the life of the mold! A release agent is essential when making a silicone body mold as it will keep the fine body hair from getting entangled in the mold. Moreover, special hair release agents are available that can be applied on the head to protect the hair and will also wash off easily.

When it comes to how to apply the mold release, first clean and dry the model or mold properly. Start by giving a light and even coat to the surface. Allow it to dry before giving another light coat or two. Here it is crucial to ensure complete coverage of the surface and yet not make the coating too thick as this may mar the minute details of the model/mold. Release agents also come in spray form and should be evenly misted on to the surface to ensure an easy demold.

The extra effort is more than worth it as the mold/cast will come off easily once it has cured. The same procedure can also be used when making two part molds.