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How to Apply Gelcoat?

•    DO NOT work in direct sunlight

•    Remove rails, cleats, louvers, snaps, striping tape, etc. Remove seals from the edges of parts or fittings when doing a repair around that part or fitting.  Clean repair area and all tools with acetone prior to application. Spray acetone to clean out Sprayer and/or vFan Airbrush.

•    Duct tape off adjacent gunwale molding, and deck fittings you are unable to remove. Duct tape is recommended over masking tape because it provides better protection.

•    Gel coat should be applied in temperatures of 60ºF to 80ºF

•    Always use eye and hand protection. Read all warnings on product labels

•    SAND DAMAGED AREA  -The heavier fast-cut grits (40/80/100) are used to feather sand and ground out a routed area prior to filling. Also, they are used for the first sanding of gouges, dock dings, scratches, and blisters. When sanding areas that have been filled with putty we suggest using 40 or 80 grit sandpaper, depending on how large the repair is.

•    Once the fill area is level or contoured to the desired shape, sand with 100 grit paper to remove the course scratches from 40 or 80 grit. You should also feather the surrounding area of the gelcoat repair with 220/330.

•    When sanding flat areas use a rubber block. We recommend 3M Abrasives for best results.

•    CATALYZE  FRESH BATCH OF GELCOAT properly. Measure catalyst accurately. Under- or over-catalyzed gel coat will cure slower and look faded or chalky.

•    Do not add more than 15-20% by volume of Styrene Monomer

•    Pot life (amount of time for application of the product) shortens dramatically as you mix larger batch sizes. Keep in mind that you have a limited time to apply what you have mixed (usually between 5-15 minutes).

•    Gel coat will not fully cure without adding a surfacing agent or over spraying with PVA

•    Spraying Gelcoat Check color thoroughly before applying. Gelcoat will not darken or change colors when it dries. The color wet is the color when dry.

•    Generally mix 5oz batches. A good practice is to pour the mixed gel coat from the mixing container into Peval Product container used for application. This further assures that no uncatalyzed material is clinging to the sides of the pot. “Lay on” the gel coat in a heavy thickness (about 10 mils) using horizontal strokes, and working from top to bottom. Avoid brushing as this could remove the waxy surface additive. Remember to always lap wet.

•    Generally, one heavy coat is sufficient. However, if you have opacity problems two coats may be necessary with a light sanding between coats. Once the coating (gelcoat) has cured, it should be block sanded using a 250 wet grit paper to remove all brush marks and high spots. Following this, it should be wet sanded with 320,400 and 600 wet grit paper, buffed, polished and waxed.

•    If there is a trim color, you need to switch the fan aircap from the  vFan Portable Airbrush System and replace it with a standard aircap. Gel Coat requires the addition of fiberglass resin hardener or catalyst (MEKP) at 2% by volume (77ºF) Measure catalyst accurately. Measure catalyst properly as using too much or too little may effect curing and cause fading and chalking. Gelcoat will not fully cure without adding a surfacing agent or wax additive sanding aid. You can spray with PVA before gel coal reaches its gel stage (5-10 min.), or adding 1oz per quart of wax additive sanding aid.

•    Gelcoat may be thinned for use in a Portable Preval Sprayer with styrene monomer. The Sprayer is an amazing spray system however Acetone is NOT recommended except in clean up. Do not use more than 15% by volume of thinner, and always add thinner, tint, OPR metal flake first then add the Catalyst or Hardener and mix thoroughly. Over thinning will result in an inadequate thickness for full curing.  

•    For more detail and precision we recommend using vFan Portable Airbrush System which works with your compressor and is designed for portability, precision paint atomization and material dispensing; for professional touch-ups and surface repairs; surface preparation; and fast curing. The vFan Airbrush delivers a 3” fan and a 1/16” hairline spray pattern.  The dual action vFan is easy to control allowing the user to manage air volume and product output. This precision-based technology allows vFan Airbrush users to atomize product finish coatings, paints and chemicals with nano-sized droplets for ultra-thin layering to feather, blend and to speed up cure times. Initially spray a cover coat as smooth and evenly as you can to cover your repair. This coat should be mostly in the repair area, and may be repeated. Sanding between coats is not necessary unless a surfacing agent has been added to your gel coat. Once your repair is covered, feather a ‘flow’ or sanding coat on the masked-off area making layered passes to avoid a buildup of gel coat in any one area.

•    Each of these coats of gelcoat may involve several passes. Be even and consistent in your Sprayer or vFan movement, overlapping each previous pass slightly and not hesitating on the ends. When spraying to a radius, flow the gelcoat to the tape. In open flat areas, layer passes. Final thickness should be 12-15 mils minimum or the gelcoat may not fully cure. As soon as you are done spraying, clean your sprayer fully with acetone. Most re-sprayed gel coat will cure in 2-4 hours, although overnight cures are ideal. Begin wet sanding with the finest grit that will remove orange peel in the re-sprayed area. This will avoid unnecessary sanding scratches. Usually 320 or 400 grit wet paper is sufficient for the initial sanding. Wet sand to a 600 finish and buff with 3M Finesse-It Marine Compound and polish with Scotchgard Marine Liquid Wax.

•    Store gel coat in a cool, dry place.