Whether to thin TotalBoat Gelcoat and how much to thin it depends on how you're applying the product and the environmental conditions. Styrene is the recommended thinner for all TotaBoat Gelcoat products. Using other commercially available gelcoat thinning products will not produce the desired results. In addition, do not use acetone to thin TotalBoat Gelcoat because it can change the color.
Thinning gelcoat for spray application
The type of spray equipment and the temperature conditions typically dictate whether and how much you'll need to thin the gelcoat. For ease in spraying, begin by adding styrene, 2-5% by volume; add more, if needed, up to a maximum of 15%, by volume. Take care when adding additional thinner because the more you add, the greater the chance of discoloring the gelcoat.
Thinning gelcoat for brush or roller application
There is usually no need to thin TotalBoat Gelcoat for a brush or roller application. If needed to help with flow, add a small percentage of styrene, 1-3%, by volume.