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The use of gel coat in composite boat construction.
Gel coat is used by OBECO as first (spray-in) layer for all boat fabrication. It serves several important purposes. One, even though the layer is quite thin, it serves as an abrasion layer that protects the fabric underneath. Secondly, pigment may be added to the layer that by its opacity provides protection to the composite laminate from ultraviolet degradation. Thirdly, some of the other resins such as vinyl ester and epoxy that may be used to manufacture composite kayaks can, if used directly in the molds from which the boat shapes are derived, can stick to the molds and prevent release of the part. This may result in damage to the molds, which is akin to a mutation in the biological world. A thin gel coat layer facilitates release of the part from the mold easily. A fourth purpose is to seal the laminate that is laid over it. For without some type of seal, applied after the part is released or before the laminate is laid up, the boat will surely have "pin holes", tiny holes in the fabric that are not filled with resin and through which water can find its way into the boat. Gel coat is the industry standard for composite boat construction and there are presently no alternatives. Gel coat is a polyester resin to which a thixotrope has been added. The "thickening agent" serves to help the resin stay in place on the mold surface and not form runs. This allows it to be sprayed into molds in very thin even layer that becomes the outer layer in the fabrication process. Although gel coat does not provide additional strength to the laminate for its weight, its advantages far outweigh any disadvantage of increased weight. Canoe polo kayaks and slalom kayaks can fabricated to weigh 7-10 kg and this very light for the size of the craft.
The gelcoat is the blue green color. Once this step is completed, the material and
resin are laid into the mold over the gelcoat. When that is complete, the deck is removed from the mold. Since the mold was specially prepared, after the meterial hardens in the mold, the gelcoat remains attached to the deck materials and separates from the mold so that the deck of the boat is color of the gelcoat shown in the picture.

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OBECO Whitewater Products 10385 - 60 Avenue NW, Edmonton, AB T6H 1H1
Dale at (780)982-1315 or Darryl at (780)982-1250   Fax: (780)463-0612
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