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A Captain's Guide to Gleaming Gelcoat

Gelcoat, like everything else on the boat, needs smart maintenance on a regular schedule.

How To Get That Gleam

There is no shortage of fiberglass products on marine store shelves, but knowing which ones to use is the best way to keep your gelcoat colors rich, true and protected from the elements.

Gelcoat is the pigmented resin that colors a fiberglass boat. It’s typically applied in the thickness of a dime. As a resin, it has no real strength; thick applications in corners with sharp bends, incorrectly sized holes or overstressed fasteners often result in unsightly, cracking veins. Gelcoat is also porous; without sealing it against the elements, exposed surfaces can fade, stain or discolor from improper washings with caustic cleaners, acid rain or simple neglect. And because of its petroleum-based formula, gelcoat ages like human skin under sunlight. It will dry out without protection unless the oil-based substrate is nurtured.

A quick test to determine the overall health of the gelcoat is showering it with a freshwater rinse. If the water beads up, then the gelcoat has some protection. When the water sheets off, it is the equivalent of driving with bald tires on an icy mountain road.

Without sufficient protection, the gelcoat will begin to oxidize, eventually fade in color, and appear chalky and dull. This progression is less noticeable on light-colored gelcoat, but it’s obvious with dark colors. Either way, your boat is begging for attention.

Fortunately, waxing is not nearly as complicated or strenuous as painting, and is easily accomplished on a schedule that fits your boating lifestyle. Best results will be achieved by using the proper maintenance products in sequence, and by following all suggested steps (read the labels on the bottles before buying any wax, polish or other maintenance product).

My first step begins with a thorough wash with Dawn dish detergent. In general, you should avoid dish detergents because a cleaner that removes grease from dishes will also remove wax on the gelcoat. However, for the initial step after a long span of abuse, it is necessary to get the gelcoat as clean as possible and remove impurities. As with paint, wax will only be as good as the surface to which it is applied. Think of oxidation as the scales on a fish you have to scrape away before cooking dinner.


If the oxidation is minor, I like to use a product designated as cleaner/wax, which contains a very fine abrasive that cuts through the old film and brightens up the surface. A cleaner/wax also does a good job of removing small scratches and light stains in the gelcoat. Cleaner/wax is not the same as a polishing or rubbing compound that has more grit; my rule is always to start with the gentlest abrasive possible, because coarser abrasives work by removing the gelcoat.

I also lean toward two applications of cleaner/wax rather than ripping into the gelcoat with harsh abrasives. As a guide, always look at the applicator pad while working. If you notice that the pad is becoming heavily tinted by the color of the gelcoat, you are working on the edge. Best to lighten up a bit.

I like using a clean sponge that remains wet and evenly spreads out the cleaner/wax, allowing just the right amount of compound to work the surface gently with sufficient elbow grease. When a sponge gets clogged and saturated, keep it in a plastic bag or aluminum foil, and get a new one. The old sponges come in handy for spot chores later along the waterline or in tight areas. If you are waxing the boat on land and drop a sponge in the dirt, toss it. You do not want to introduce that type of grit near your gelcoat.

Once the cleaner/wax has dried, buff the surface with a clean terry towel or microfiber cloth. If you use a power buffer, do so gently to avoid creating swirls from burning the compounds into the gelcoat. Even without a power buffer, cleaner/wax used by hand will surprise you with good results.

My next step is a thorough coat of liquid wax that nourishes the gelcoat, followed by buffing with another clean towel. I will follow that step with a second or third coat that adds more brilliance and protects my boat from salt, sun, bird droppings and airborne dirt. Midway through summer, I will take another day and add another coat of wax, or touch up any worn areas that need attention. Maintaining gelcoat is best handled on a regular schedule instead of once a year.

When you are happy with the way your boat looks, you can protect your hard work by keeping the boat clean. Unlike a car that sits in a garage, your boat is out in the weather 24/7. Birds use it for target practice, and rainwater drizzles on it from top to bottom (collecting dirt and leaving streaks of grime on its way to the waterline). Frequently, though, if the wax is doing its job, these blemishes wipe off with a wet cloth or soft brush.

To protect the wax, always use boat or RV soap with a label stating that it will not remove wax. I have actually found that with ample wax on the gelcoat, soaping is not always necessary. A good rinse with clean water prevents the dirt from collecting, and keeps the shine intact.

7 Tips For Your Next Wax Job

1. Use a chamois for metal and windows, and a squeegee for the fiberglass. After washdowns, you can prevent water spots by wiping the boat dry with a clean towel. If you use a chamois, however, and notice white dust when you wring it out, you are actually removing the wax. After you squeegee the fiberglass, do a quick wipe with the towel or chamois for the remaining drops.

2. If you use liquid wax, or liquid polishing or rubbing compounds, be sure to shake the bottle before and while using the product, to keep the contents mixed.

3. When waxing large areas such as the hull, deckhouse or flybridge wings, tape off vertical sections top to bottom, and finish each one before moving on to the next. This technique will ensure that you have properly waxed each area without skipping any portions.

4. Say goodbye to stains. Ground-in stains on nonslip gelcoat surfaces often surrender to an application of Soft Scrub or similar liquid cleanser. Special formulas in these products are designed to lift out the stain rather than grind it away.

5. Use a chemical cleaner rather than a liquid compound for rust stains on gelcoat. Liquid rust-stain cleaners dissolve the oxidation, but require utmost attention not to damage other surfaces. These cleaners also work well for removing hull stains and “mustache” waterline discoloration. A gel rust-stain remover is more user-friendly. Wear gloves and eye protection when using these industrial products.


6. When employing a power buffer, change the pad frequently, or clean it regularly every few feet so you are not spreading the wax it buffs back into the gelcoat. Be alert when buffing near hardware or other fittings that could snag the pad and cause you to lose your grip on the machine.

7. Always start in a small area and see how well a new product works before going full steam ahead. Check the instructions on the container, and follow the recommended safety advice.