When working with polyester, epoxy, or other casting resins where you are casting something in a mould, a good release agent is indispensable. A release agent ensures that your mould and finished product separate cleanly without damage. But which type of release agent to use for which purpose? In this article, we explain the difference between release wax and PVA (polyvinyl alcohol) and help you choose the right one for your project.
A release agent forms a barrier between your mould and the material you are casting or laminating. This prevents the finished product from sticking to the mould, which can be frustrating and may damage both the mould and your workpiece. Two commonly used release agents are:
Each has its own properties and applications.
Release wax is a popular choice when working with smooth, non-porous moulds, such as polished polyester or metal moulds. The wax is applied thinly and then buffed off. Multiple layers are often required, especially for a new or untreated mould.
Benefits of release wax
When to use release wax
PVA (polyvinyl alcohol) is a liquid, water-soluble film applied over the mould. Once dry, it forms a visible protective layer between the mould and the resin. PVA is often used on new moulds, complex shapes, or materials where adhesion is more likely, such as wood, plaster, or unpolished moulds.
Benefits of PVA
When to use PVA
In some cases, both agents are used together. This is especially recommended for new moulds, complex shapes, porous materials, or important projects where reliable release is crucial. For extra release security, combine wax and PVA as follows:
The wax fills tiny imperfections and creates a smooth surface, while the PVA forms a visible physical barrier.
Always pay attention to the following when combining release wax and polyvinyl alcohol:
Use the right polyvinyl alcohol
Some PVAs contain solvents that can affect the wax layer. always use a good quality PVA, such as RESION polyvinyl alcohol.
PVA is fragile when handled
Let PVA dry completely (30-60 min.) and avoid touching afterwards to prevent damage.
Do not use in reverse order
Never apply wax over PVA! Wax will not adhere properly and both agents will lose their effectiveness.
End result: no high gloss without post-processing
PVA leaves a matte film on your workpiece. You can rinse it off with water, but if you want a high-gloss finish, polishing is usually required afterwards.
See the table below to find out which release agent is suitable for your application.
| Application | Release wax | PVA | Wax + PVA |
|
Smooth, polished mould |
Yes |
Optional for extra protection |
Best choice for new moulds |
|
New or porous moulds |
Limited effectiveness | Yes | Yes |
|
High-gloss finish without post-processing |
Yes | No | No |
|
Difficult-to-release shape |
Limited effectiveness | Yes | Best solution |
|
Single-use mould (e.g., wood or plaster) |
Not suitable | Yes | Best solution |
At Polyestershoppen.com, you can find high-quality release waxes and PVA release agents. Our product specialists are happy to help you choose the right product for your application. Do you have questions about your specific project? Feel free to contact our customer service team— we’re happy to advise you!
Use PVA for new, porous or complex moulds. Wax is better for polished, reusable moulds with smooth surfaces.
Yes. Apply 3 to 5 layers of wax first, let each layer dry and buff it. Then apply a layer of PVA for maximum release reliability.
Yes, especially with new or untested moulds. Epoxy bonds strongly, so using both wax and PVA gives better results.
Yes, PVA leaves a visible matte layer. It can easily be rinsed off with water after demoulding.
Use wax on smooth, non-porous moulds such as polished polyester or metal. It’s ideal for reusable moulds with a clean finish.
For a new or untreated mould, apply 5 to 7 coats. For a previously used mould, 1 to 2 coats is usually enough.
Yes. Let the wax dry for 5 to 10 minutes, then buff it with a soft cloth to create a shiny, even layer.
No. Wax is not suitable for porous surfaces like wood or plaster. Use PVA instead, or combine wax with PVA.
No. Wax leaves no visible film, which makes it ideal for high-gloss finishes without extra polishing.
Do you have a specific question? Call one of our specialists for free advice +3185 0220090
