Is It Normal for Gel Coat to Be Sticky, and How Can It Be Solved?

Q: Is It Normal for Gel Coat to Be Sticky, and How Can It Be Solved?

It is common for polyester gel coat , when used as the first layer, to retain a slight stickiness. This helps achieve better cross-linking with subsequent resin layers. However, if the gel coat remains sticky when used externally (such as on the surface of a product), it can pose a problem, especially when repairing molds or applying surface refinishing coatings. To address stickiness, you can add a wax solution to the unsaturated polyester or vinyl ester gel coat (typically at a ratio of 2-5%). This wax solution, made from paraffin and styrene, will form a very thin barrier between the gel coat and the air during curing, allowing the wax to polymerize at the surface, resulting in a hard, non-tacky finish. However, for large-scale gel coat renovations, it is advisable to use air-dry gel coats rather than adding wax solutions. Adding wax can lead to potential bonding issues and reduce surface gloss.

It is common for polyester gel coat, when used as the first layer, to retain a slight stickiness. This helps achieve better cross-linking with subsequent resin layers. However, if the gel coat remains sticky when used externally (such as on the surface of a product), it can pose a problem, especially when repairing molds or applying surface refinishing coatings.

To address stickiness, you can add a wax solution to the unsaturated polyester or vinyl ester gel coat (typically at a ratio of 2-5%). This wax solution, made from paraffin and styrene, will form a very thin barrier between the gel coat and the air during curing, allowing the wax to polymerize at the surface, resulting in a hard, non-tacky finish.

However, for large-scale gel coat renovations, it is advisable to use air-dry gel coats rather than adding wax solutions. Adding wax can lead to potential bonding issues and reduce surface gloss.