#Industry News
Building Boats: Gelcoat
Taking a closer look at what goes into a first-rate finish.
The first of an infrequent series of articles designed to help you better understand boat design and construction.
Fight for the Finish
Let’s start at the top with a glimpse at what goes into a first-rate finish. While we could have chosen from a select number of boatbuilders as an example, we’re going to detail the techniques employed by Cobalt Boats to achieve long-lasting good looks.
Mold Maintenance
The finish of a molded part depends upon the quality of the mold. Any imperfection in the mold surface is likely to show on the outside of the finished product, particularly in sunlight. So a strict regimen of mold maintenance is mandatory.
In Cobalt’s case, this includes polishing by hand between every boat. Though an electric polisher would make the job quicker, even in experienced hands these leave slight swirl marks that might be mirrored in the final finish. Going for “best” leaves little room for compromise, takes longer and costs more. So the molds get polished by hand.
Another way in which Cobalt achieves its heralded finish is by allowing parts to cure in the mold longer than the industry average. The exact times aren’t that critical to cite, since various molding techniques and choice of materials all dictate the optimal in-mold cure time. Suffice it to say that builders that allow the parts to cure longer end up with better-looking boats. The reason? With the part cured more fully, it’s stiffer and harder, and so it’s less subject to damage when being pulled from the mold.
What Lies Beneath
Any boat can look good for the duration of a boat show. But a truly good finish, in our opinion, stays looking good on the water, in the sun and for the long term.
Gelcoat is brittle, as far as resins go, and if the underlying structure moves a lot or shrinks and expands too much, even the highest-grade gelcoat applied to the best-maintained molds is not going to hold its showroom looks.
Cobalt bonds the stringer system to the hull with methacrylate adhesive, ensuring fluid paths for the loads that a boat must withstand under way. Fittings are backed with plates, so when a cleat is loaded, the laminate doesn’t flex enough to cause stress cracks. Kevlar reinforcement is used in key stress areas to ensure the stiffness required for parts to retain their shape at high speed in rough water.
Material Wealth
Builders like Cobalt use custom-blended gelcoats. But there’s more to a fine finish than just the quality of the finish material itself. I encourage you to tour the plant before buying any new boat. You’ll see that much more goes into a shine than just some wax and elbow grease.
