Mold Release Products

What Are Mold Release Products?

Mold release products are specially formulated agents — available as liquids, paste waxes, and aerosol sprays — that create a barrier between a mold surface and the material being cast or cured within it. In marine and RV applications, these products are indispensable whenever fiberglass hulls, decks, gelcoat panels, and composite parts are manufactured or repaired. Without a proper release agent in place, cured resins and gelcoats can bond permanently to the mold, ruining both the part and the tool.

Why Mold Release Matters in Marine & RV Work

Fiberglass construction is the backbone of modern boat and RV manufacturing. Whether you're laying up a new hull, spraying fresh gelcoat, or making a custom composite component, a reliable mold release agent determines the quality of the finished surface. A well-applied release barrier allows a smooth, glossy parting film to form between the mold and the laminate, protecting the mold's integrity and ensuring clean, repeatable part removal across multiple production cycles.

Marine environments are especially demanding — hulls and decks must withstand constant water exposure, UV radiation, temperature swings, and physical stress. The same resilience required of the finished part is also expected of the mold release agent used during its creation. Choosing the right product for your resin system (polyester, epoxy, or vinyl ester) and your mold material (fiberglass, metal, or plug) is critical to a professional result.

Types of Mold Release Agents

• PVA (Polyvinyl Alcohol) Liquid Releases: Water-soluble films that are sprayed over the mold surface. They form a thin, peelable barrier that promotes a full cure of polyester gelcoat and eliminates surface tackiness.
• Paste Wax Releases: Carnauba- or silicone-based waxes buffed onto mold surfaces to provide a durable, multi-cycle parting layer. Ideal for production runs where many identical parts will be pulled from the same mold.
• Aerosol Spray Releases: Convenient spray-can formats for quick, even coverage on complex or hard-to-reach mold geometries.

Top Brands in Mold Release Products

Evercoat is the top-selling brand in this category and a long-trusted name in marine repair. Their PVA Mold Release is a water-soluble liquid that forms a smooth parting film for a glossy finish on molded surfaces, and it serves double duty as an air-inhibiting agent that promotes a full cure of polyester gelcoat — eliminating the tacky surface feel that plagues improperly cured laminates.

Rexco brings decades of composite industry expertise to their mold release lineup. Their Partall product family includes both PVA liquid parting films and paste wax releases — including the well-known Formula Five, a silicone-based paste that blends carnauba wax with modern polymers for reliable multi-cycle releases on demanding fiberglass and composite molds.

WhaleSpray offers a range of aerosol mold release agents, including H1-certified silicone formulations designed for applications where low toxicity and clean release are essential. Their sprays are well-suited to maintenance and repair scenarios where quick, consistent coverage is a priority.

Sprayon rounds out the category with industrial-grade aerosol release agents known for broad material compatibility and ease of use in both shop and field environments.

Choosing the Right Mold Release

Match your release agent to your resin system: PVA films pair naturally with polyester and gelcoat applications, while paste waxes work well for production molding with repeated pulls. Always apply release agents to a clean, properly prepared mold surface — contamination is one of the most common causes of release failure and surface defects in finished fiberglass parts.