Re: gelcoat

Posted by Alex Meller on May 17, 2004

Gel-coat works best sprayed into a mold, with a polyester boat layed up on it.

You can get gelcoat to stick to epoxy, but it is not a particularly strong bond.

I have owned several light weight sailing dinghies built of epoxy (glass, Kevlar and honeycomb core). Since epoxy gelcoats are not really available, polyester is used. The gelcoat is sprayed into the mold and then the epoxy hull is vacuum bagged in the mold.

Then when the boat is dinged, you have to do the outer layer of the repair with gelcoat matching the original.

Gelcoat does not flow out to form a smooth coating nearly as well as high quality paints. Brushing on gelcoat, and getting enough on to cover everywhere will most likely result in a thick, heavy, coating, with noticeable brush marks. Then you will spend hours-and-hours sanding that down to a smooth surface and then polishing.

People who are good at gelcoat repairs frequently spray it, and this can be done using a cheap disposable "Pre-Val" sprayer (about $8.00). Spraying ususally results in much less sanding than does brushing on.

A two part polyurethane carefully brushed on will give you a smoother finish with much less work. The two part polyurethane will be slightly more brittle than the gelcoat, but more durable in other ways. It will also fade less quickly.

Alexander "Ali" Meller

In Response to: Re: gelcoat by LeeG on May 17, 2004