UV Curing Additive

UV Curing Additive for Polyester Surfboard Resin

UV Curing Additive is a powdered photo-initiator designed for polyester-based surfboard resin systems. When mixed into compatible polyester surfboard resin, it allows the resin to stay workable while kept away from direct UV exposure, then cure quickly once exposed to sunlight or a proper UV light source.

This additive works best with Silmar 249A/B polyester surfboard resin, making it a great choice for surfboard building, ding repair, laminating, hot coats, sanding coats, fin work, and other fiberglass surfboard repair applications.

Instead of rushing against a traditional MEKP cure window, UV Curing Additive gives you more control over your working time so you can apply the resin properly before starting the cure. Once exposed to UV light, the resin begins curing quickly, helping reduce wasted resin and making small repairs or production work more efficient.

Features

• Made for polyester-based surfboard resin
• Works best with Silmar 249A/B polyester surfboard resin
• Converts compatible polyester surfboard resin into UV/sun-cure resin
• Extends working time until exposed to sunlight or UV light
• Cures quickly once activated by UV exposure
• Ideal for surfboard glassing, hot coats, fin work, ding repair, and laminating
• Useful for sanding resin and fiberglass surfboard repair
• Powdered additive mixes directly into polyester resin
• Helps reduce wasted resin from resin kicking too early

Mix Ratio

Use approximately 7 grams / 7 cc of UV Curing Additive per 1 gallon of polyester surfboard resin.

Mix thoroughly until the powder is fully dispersed before use.

Application Notes

Keep mixed resin away from direct sunlight, windows, or strong UV exposure until you are ready for it to cure. Apply the resin indoors, in shade, or under controlled lighting.

Once the laminate, hot coat, repair, or fin work is ready, expose it to direct sunlight or a proper UV curing light to begin the cure.

Cure speed may vary depending on sunlight strength, resin type, resin thickness, temperature, and UV exposure. For best results, test a small batch before full use.

Compatibility Note

UV Curing Additive is intended for polyester-based surfboard resin systems and works best with Silmar 249A/B.

For areas that cannot receive proper UV exposure, or when a traditional chemical cure is preferred, MEKP may still be used as directed for the resin system.