What is a gel-coat and what is it for?
Gel-coat is basically a relatively thick layer of resin with colorant added. In the manufacturing process it is the first layer of the hull, sprayed against the inner surface of mold. Its smooth shiny finish is an indicator of the mold finish. Any mold imperfections would be reflected in the gel-coat as well. Functionally, it serves as a protective finish to the structural portion of the hull's composite lay-up, particularly against abrasion. The gel-coat also provides a barrier to moisture penetration into the weave of the hull lay-up.
Is there anything special about the resin used for gel-coats?
Yes, the resin is formulated specifically for this purpose. It tends to have a high elastic capacity and is engineered to provide superior strength without an inherent cloth structure as well as exceptional abrasion resistance.
What is a skin-coat?
Skin-coat boats are boats made without a true gelcoat. There is a layer of resin applied to the mold surface and the hull is laid up directly on that layer of resin. This construction is performed generally only when minimum weight is the goal such as for marathon and triathlon racers. These boats are usually much better taken care of than most recreational boats nor are they exposed to hazards as freely. Skin coated boats are lighter than gel-coated ones but are also more subject to porosity which can allow moisture to penetrate into the structural lay-up and cause deterioration.
Are clear-coated boats skin-coated?
No. you can obtain clear-coat as a gel-coat. The same resin mix used in a gel-coat is used but no coloring has been added. This will lighten the boat a little as pigment does add weight. The disadvantage is discoloration of the lay-up fabric upon sustained exposure to UV light.
Why does my canoe seem to show every scratch?
Every paddler knows scratches are inevitable and regardless of the color of the gel-coat, all scratches show up as white. This makes them very evident. Some paddlers will go so far as to select a white or sand colored hull to minimize this effect.
Are the scratches something to be concerned with?
Not as long as they remain strictly a cosmetic issue. When scratches are deep enough to reveal the internal cloth's weave, it is time to take corrective steps.
Why does the gel-coat chip on the stems of my boat?
Two reasons. The biggest is that this is the most likely place for the boat to sustain an impact. Additionally, the gel-coat is thickest as it wraps around the stem of the boat. This does weaken the bond between the gel-coat and the structural layers and when subjected to a sharp impact can be chipped away. Be thankful, for this is actually the gel-coat doing its job. Often the damage will be limited to the loss of a small piece of gel-coat with the underlying lay-up escaping any damage,
Is gel-coat difficult to repair?
No. It takes some patience and some thoroughness to generate the best possible finish but that's pretty much up to you. Basically, you'll be filling a scratch, gouge chip, or hole with new additional gel-coat and then sanding and polishing to fair it in and bring up the shine. Deep scratches, holes, or chips may require multiple applications of gel-coat but this is not really a time consuming procedure.
Is the repair hazardous?
Not if you wear the gloves provided and use safety glasses and a NIOSH certified respirator for Dust and Mists. It's best done outside and on a day with temperatures between 68-75°F for sufficient working time.