Gelcoat Repair Kit - Pure White Gelcoat With Wax, Hardener & Tinting Pigments

SKU:GEL-RK-W025

$64.95 USD

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107 in stock

Size: Quart

Quart Gallon

Quantity

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Professional grade isophthalic gelcoat kit for marine, automotive, and composite repairs. Lay your build coats straight from the can: unwaxed gelcoat stays recoatable, so each coat bonds to the last without sanding. Stir the included surfacing wax into the final coat only, about 1 oz per quart, and that coat cures tack-free and sands clean.

Most boat white is not pure white. Factory and weathered off-whites lean warm or grey, and these two pigments are the ones that take you there: a touch of yellow warms it toward cream or ivory, a touch of black cools it toward grey. Tint a small test batch a drop at a time and let it cure before you judge it, because the color shifts as it cures.

What's in the box:

1 quart pure white ISO/NPG gelcoat, unwaxed (1 gallon in the gallon kit)
1 oz MEKP hardener (2 oz in the gallon kit)
2 oz surfacing wax for the final coat (16 oz in the gallon kit)
1 oz Carbon Black and 1 oz Bright Yellow liquid pigment
2 inch natural bristle chip brush (two in the gallon kit)

You supply: mixing cups, stir sticks, nitrile gloves, and sandpaper for prep and finishing.

Ideal for boat hulls, decks, bathtubs, and fiberglass restoration projects where durability and finish quality matter.

Specifications

Technical specifications

Gelcoat: pure white, ISO/NPG, unwaxed
Surfacing wax: included as a separate bottle, 1/2 to 1 oz per quart, final coat only
Pigments: 1 oz Carbon Black and 1 oz Bright Yellow liquid pigment
Catalyst: MEKP included, 2% by volume: 19 cc (2/3 oz) per quart, 76 cc (2.5 oz) per gallon; 1.5% hot to 2.5% cold
Sizes: quart kit and gallon kit

Includes

Pure White Gelcoat, unwaxed
MEKP Catalyst
Surfacing Wax, separate bottle
Carbon Black + Bright Yellow Pigments
Chip Brush

Features

Pure white ISO/NPG gelcoat, MEKP, surfacing wax and black and yellow tinting pigments in one kit
ISO/NPG marine gelcoat
Tint to the hull color, catalyze, and wax the final coat so it cures tack-free
Build coats stay recoatable; add the wax only to the last one
Black and yellow tints, the two that move pure white toward an off-white

View full details

How do I repair a gelcoat scratch or chip?

Clean the area with acetone, then sand or grind the damage to a slight V so fresh gelcoat can key in. Mask around it, mix gelcoat with the right amount of MEKP, and add surfacing wax to the final coat so it cures tack-free. Apply slightly proud of the surface, let it cure, then wet-sand from coarse to fine and buff to a gloss. Match the color first with pigment on larger or visible repairs.

How do I color-match gelcoat to my boat?

Start with a neutral or white base gelcoat and add polyester-compatible pigments a little at a time, testing on a scrap or hidden spot until the cured color matches. Cure shifts the shade slightly, so judge the match after it kicks, not while wet. Older hulls fade, so you may need to tint a little off the original to blend. For a solid white hull, a pure white gelcoat often matches with no tinting.

How do I apply polyester gelcoat?

Clean and sand the surface, then catalyze the gelcoat with MEKP and lay it down in two to three coats. Spray it at about 18 to 20 mils wet, or brush and roll thinner coats, letting each one flash before the next. Because polyester gelcoat is air-inhibited, the final coat needs surfacing wax (or a PVA film) to cure tack-free so you can sand and buff it.

How much MEKP do I add to gelcoat?

Catalyze polyester gelcoat at about 1% to 2% MEKP by volume, with 1.25% a good starting point near 70°F. That works out to roughly 1.5 to 2.5 ounces of MEKP per gallon of gelcoat. Use a little less in hot weather and more when it is cold, and always follow the ratio printed on your MEKP. Do not exceed about 3%, which can crack or discolor the coat.

Do I need to add wax to gelcoat?

Only if you are using unwaxed (sanding) gelcoat. Unwaxed gelcoat stays tacky on the surface because air stops polyester from curing, so you add surfacing wax to the final coat, or spray PVA over it, to seal out air and cure it hard for sanding. Our Finish Kits ship the wax as a separate bottle with the gelcoat: lay your build coats unwaxed so they recoat without sanding, then stir 1/2 to 1 oz of wax per quart into the last coat only.

Why is my gelcoat still tacky and not curing?

A tacky surface almost always means air-inhibited cure, not too little catalyst. Unwaxed gelcoat will not harden on top until you add surfacing wax to the final coat or seal it with PVA. Other causes are too little MEKP, temperatures below about 60°F, or high humidity. Confirm your catalyst ratio, warm the shop, and wax or PVA the last coat.