Gelcoat Care and Restoration

By Brian Gordon, Last updated: 4/2/2019

Pride of Ownership

Family washing a Wave Runner

Maintenance becomes a family affair!

Owner apathy and dull, tired gelcoat go hand in hand. In the opinion of some owners, bright, shiny boats don’t sail any better or catch more fish, so why bother with maintenance? But keep in mind that maintaining your boat’s gelcoat will help you “catch” more customers should you ever want to sell.

If You Have a New Boat . . .

If you happen to be the owner of a fresh-out-of-the-mold, brand-spanking-new boat, you are in luck. Why? Because unlike other owners, all you need to do is wash your boat and apply a quality wax. Waxing your boat now will protect that like-new look and head off a time-consuming restoration project down the line.

About Gelcoat

Gelcoat is the coating sprayed up against a highly polished mold at the beginning of the fiberglass layup process. This process results in the smooth, mirror-like finish typical of new boats. With the passage of time, unprotected gelcoat will oxidize and eventually take on a chalky appearance. As part of this process, it becomes porous. The more porous it becomes, the more readily it will stain. The process continues until the boat becomes one of the dilapidated wallflowers that we have all seen at the dock. The good news is that nearly all gelcoat can be restored, provided it is not completely worn through.

Four Steps to Gelcoat Restoration

West Marine heavy duty boat soap

Marine boats soaps like this one are low-sudsing formulas that are better for the marine environment.

Step one: Remove all surface dirt. To remove the surface dirt, wash your hull and topsides with marine boat soap diluted in water. Apart from rinsing residue-free, marine boat soaps are better for the environment compared to popular dishwashing liquids, most of which are high in sulfonates and should be avoided.

Sometimes, molded-in non-skid areas can be difficult to clean. In this case, try using a chelating non-skid cleaner. These cleaners are formulated to break the bond between the dirt and the deck without heavy scrubbing.

After removing the surface dirt inspect for damage. Look for stress cracks around stanchions or other areas that might be an indication of an underlying structural problem. If you have any surface scrapes or gouges that need repair, check our Advisor “Do-it Yourself: Gelcoat Repairs” which includes an instructive video that covers gelcoat restoration, scratch repair, and polishing and waxing techniques.

Step two: Remove the stains. Nearly all boats have some degree of gelcoat staining. Unfortunately, mere soap and water frequently won’t remove all the stains, which exist at a deeper level within the porous gelcoat surface. Stains can be localized or in the case of some boats cover the entire topsides and hull. There are two types of stains: mineral and organic. Mineral stains include rust stains and “black streaks”. Organic stains include discoloration due to bird droppings, coffee, wine, and leaves.

Stain on a boat gel coat

Acid-based stain removers are the ticket for removing what you see here.

Acid-based stain removers are effective for removing most mineral and organic stains. Acid-based stain removers packaged in the form of a gel are the easiest to use, because they hold well to vertical surfaces and because they work chemically, with little or no scrubbing required.

When using an acid based stain remover, wear rubber gloves, eye protection, and keep it off of paint, varnish, or galvanized surfaces, as it may dull these areas.

Due to air pollution, many boats are stained over their entire surface. This may not be readily apparent, but as a quick check, try swabbing some of the gel stain remover across an area that otherwise looks ok. Allow the gel to remain for 20 minutes and then rinse it off. If the color changes (whites will become whiter, colors will brighten) you have general staining. To return the boat to its original color, you can use the gel stain remover over the entire topsides and hull.

Besides acid based stain removers, there are other formulations that target specific types of stains. These include black streak removers, rust stain removers, exhaust stain removers, mold stain removers, and even bird and spider dropping stain removers. So if you have trouble removing any of these, try using a stain remover specifically formulated to take them out.

Davis fiberglass stain remover

This acid-based stain remover is a gel formulation that holds well to vertical surfaces.

Step three: Remove the oxidation and restore the shine. Unless your boat is very new, it most likely will have some oxidation. Light oxidation manifests itself as a slight dulling of the gelcoat. Moderate to heavy oxidation can be seen in gelcoat that has a chalk-like powder at the surface.

Before selecting a polish, it is important to understand that polishes and their more aggressive cousins, rubbing compounds use abrasives to smooth the pitted surface of porous gelcoat and restore the shine. If your gelcoat is heavily oxidized, you might need to start out with rubbing compound and then follow up with successively finer grades of polish. Bear in mind that each time these products are used, some of the gelcoat is removed. Therefore, care should be taken to use the least aggressive product that will get the job done. Polishes and rubbing compounds can be applied by machine or by hand.

Step four: Protect the shine with a wax. Once you have polished the surface and removed the stains, it is time to seal and protect the surface with a wax. In addition to sealing out oxygen, which prevents oxidation, many waxes contain inhibitors that protect gelcoat against damaging UV light. There are several types of wax, each of which has its adherents. Choices include pure carnauba, carnauba polymer blends and polymer only formulations. Wax, like polish can be applied by machine or by hand. Do not apply wax under direct sunlight.

Molded-in Non-Skid

Aside from washing non-skid areas and possibly removing the stains, most people leave their molded-in non-skid alone. This is because they believe that polishing and waxing non-skid will make it slippery. For old, worn non-skid this may be true. But for non-skid that is in good condition, Shurhold Industries has shown that it can indeed be polished and protected without a loss of traction. For an informative video on the Shurhold system, click in the viewer at the bottom of this article.

One-Step Formulations

Shurhold dual-action polisher

Shurhold’s Dual-Action Polisher bridges the gap between harder-to-use heavy-duty circular polishers and common automotive-style buffers.

Conventional wisdom dictates that gelcoat polishing and waxing should always be performed as separate operations. While we are confident that the four-step procedure outlined above will result in a bang-up job of which you can be proud, alternatives exist.

Bucking tradition are one-step products that combine a polish with a wax. “Purists” might disagree, but in cases of light to moderate oxidation, one-step products make perfect sense. After all, why spend all day on a project when you can finish the job in half the time!

Polishing Machines

There are two types of machines that you can use. The first are variable speed circular polishers, which in the hands of a pro can quickly cover a lot of ground. But when used by a novice they can “burn through” and mar the gelcoat surface. Therefore, we suggest that unless you are experienced, you use a random orbital polisher. These are available with built-in rechargeable batteries and also as AC plug-in units. If you plan on using an AC machine with your boat in the water, make sure the machine is GFCI-protected, since water and electricity are a dangerous combination.

Polishing Technique

optimal buffing patter for consistent results

For even, consistent results, follow this pattern when buffing or polishing with a machine.

When polishing or applying wax by hand or machine, work small areas in a circular manner and don’t move on until each area is done. For more on the proper way to polish gelcoat and apply wax, check our Advisor “Do-it Yourself: Gelcoat Repairs” which includes an instructive video that covers gelcoat restoration, scratch repair, and polishing and waxing techniques.


Once you have finished the restoration, all you need to do is follow up with regular wash downs and periodically apply a fresh coat of wax. Now kick back and enjoy the compliments!

Required Tools and Supplies

  • Medium or coarse deck brush
  • Soft-bristled handheld brush
  • Chamois
  • Cotton rags
  • Goggles
  • Kneepads
  • Bucket
  • Hose with nozzle
  • Boat soap
  • Polish
  • Wax


  • Random orbital polisher or circular polisher (AC units must be GFCI-protected)
  • Polishing and buffing pads

Waxing Non-Skid

Click in the video viewer below for a demonstration of how to wax and protect gelcoat non-skid against the damaging effects of weather and the sun.