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What can you use as a mould release agent?

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Mould release agents are important for the manufacturing of vehicle parts. They prevent hardening material from bonding to a mould; that is, the rigid frame that is used to shape liquids or raw material in the car manufacturing process.

In this article, we’ll ask what mould release agents are, how they work, and discuss the various type of substances that can be used as mould release agents.

What are mould release agents?

Mould release agents are used in the manufacturing of vehicle parts produced from materials such as fiberglass, carbon fiber and plastic. They can be particularly useful for making custom vehicle parts including interior parts, body panels spoilers and other accessories from these materials.

You can use mould release agents made with wax, silicone, solvents and water. We’ll come on to these options in more detail later in this article.

When applied correctly, mould release agents can be fundamental to the production of perfect vehicle parts. Not only that, but they preserve the mould for future use and reduce labour time.

How do mould release agents work?

The agents are applied by brushing, wiping or spraying onto the surface of the mould, before the moulding material is added. It is essential that the mould release agent is compatible with the material of the mould itself.

Some mould release agents – such as those made from silicone or wax – form a physical barrier that separates the mold and the hardening material. It is this that effectively prevents bonding during the curing process.

Other mould release agents interact chemically with the surface material of the mold to stop the setting material sticking to the mould after setting.

An effective mould release agent will improve the flow of the moulding compounds across the mould. This makes filling detailed areas easier and results in accurate feature definition.

What can you use as a mould release agent?

Mould release agents can be split into four main types. Each has its own properties, and some are more suited than others to certain applications.

Let’s put a spotlight on these types of mould release agent:


Wax-based mould release agents can be seen as traditional agents, having been on the market for the longest time. They are usually produced from beeswax, carnauba and other natural waxes.

Among the advantages of wax-based mould release agents is that they offer an effective release for the majority of materials and are fairly simple to apply. On the flip side, wax-based mould release agents are not designed for high-temperature applications. Wax-based mould release agents are usually used for low-temperature moulding with materials such as plastics, compsosites and rubbers.

Wax-based mould release agents create a barrier between the inner layer and surface of the mould. This stops adhesion and prevents the mould from becoming damaged.

These type of release agents come in a liquid or a paste. The liquid versions are simple to apply evenly, can effectively release most materials quickly, and are typically used with large or complex moulds. Conversely, the wax-based release agents coming in paste form are better for smaller moulds and offer a more durable barrier.


Silicone-based agents offer high-performance release – due to their thermal stability – and are versatile enough to be used in a broad variety of applications. Despite this flexibility, there are some materials that silicone-based mould release agents are not suitable for.

From sprays to emulsions and fluids, silicone-based agents come in several forms. They work like any mould release agent, creating a barrier between the surface and inner layer of the mould, preventing the two materials from sticking together.


Solvent-based mould release agents work by delivering active silicone or wax ingredients onto mould surfaces. Solvents that are commonly used for this include mineral oil, xylene, acetone and toluene.

Advantages of solvent-based agents include their quick drying time, which makes them especially suited to high-volume manufacturing. They are also ideal for the wetting of detailed mould surfaces and precision surface transfers. They can be sprayed onto cloths for quick application by wiping, even on large or complex moulds.


Water release agents are a type of solvent-based release agent. They are different from traditional solvent-based release agents such as mineral oil, in that they are safer and less expensive, not to mention more environmentally friendly. Because water-based mould release agents have a lower viscosity and are less thick, they are easier to apply evenly.

Water-based agents are most commonly used in medium- and high-temperature applications. They offer a combination of effective release performance and the ability to protect moulds from rust over time.

That’s a wrap on our overview of mould release agents, which are a vital facilitator in modern-day automotive production.

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