Polynt Group 23

The primary reason for using tooling gel coats for the manufacture of fiberglass molds is to produce a blemish-free, durable, high-gloss surface. It is advantageous to exercise strict quality control and application procedures when using tooling gel coats. Proper application is very important, since many of the defects that result from poor application do not appear until the part has been removed from the mold. Many gel coat defects result from conditions that can easily be corrected. A few of these are listed below: · Do not use varnish as a sealer or finish coat when preparing a plug, as the styrene in the gel coat will soften the varnish, even when well-waxed and coated with a parting film. · Proper spray technique is very important to eliminate porosity in the gel coat film. Internal air-atomization spray equipment, airless, or catalyst injection spray equipment can result in porosity in the gel coat film if improperly applied. Tooling gel coats will not be as tolerant of inaccuracies in a catalyst injection system as are production gel coats. · Tooling gel coats appear thick in the container. After mixing the gel coat, it becomes sprayable. Do not overmix, however. Overmixing breaks down viscosity, increasing tendencies to sag and causes styrene loss, which could contribute to porosity. Tooling gelcoat needs mixing when opened (and daily thereafter). The gel coat should be mixing to the sides and bottom of the container with the least amount of turbulence possible. Air bubbling should not be used. It is not effective and only serves as a potential for water or oil contamination · Always keep the container covered (except, of course, when transferring material). An open container is easily contaminated and allows for more styrene evaporation. · Each coat must cure as a total film, rather than several thin films which might cure independently of each other. It is essential to cover overspray and thin passes as soon as possible--within 5 minutes. Thin, independently curing films can create a textured effect when the surface is sanded and buffed · Never reduce tooling gel coat with a conventional paint or lacquer thinner, or acetone. · Disperse catalyst thoroughly in tooling gel coat. Poor distribution causes uneven cure, print-through, and premature release from plug before lay-up. · Do not over-catalyze. Excess catalyst plasticizes tooling gel coats. · Print-through (fiber pattern) and distortion are directly proportional to film thickness. Thicker films (not to exceed 40 mils wet total) resist print-through and distortion better

Uncatalyzed tooling gel coats have a usage life of 45 days from date of manufacture when stored at 22°C or below in a closed, factory-sealed opaque container and out of direct sunlight. The usage life is 45 days if stored at 33°C and 22 days at 45°C.