Updated: Sep 10, 2021
Few things irk this boater more than dirty, chalky and stained gelcoat. Like an engine that is corroded—or lines that are chafed—worn gelcoat is a sure sign of neglect. Fortunately however, there are multiple ways to restore aged, stained, dirty and faded gelcoat. With a bit of care and a lot of elbow grease, the methods below are guaranteed to drastically improve the appearance of one’s craft. If perfection is sought, the reader may instead seek a professional two-part polyurethane paint job.
Method 1: Cleaner Wax/Polish
Method 1 is the simplest and least laborious of the three methods outlined herein and is applicable only to newer boats with surface stains, minor fading and discoloration of the gelcoat, and little to no oxidation. To determine if gelcoat is oxidized, wipe your hand across the surface. If any “chalk” wipes off on your fingers, the gelcoat is oxidized and will need to be washed and buffed before polishing.
If you are lucky and all your boat requires is a light polish, here are the steps to achieving a beautiful finish:
Gather your supplies: you will need a pack of high quality microfiber towels and a polish. Low quality towels will shed and leave streaks and residue.
For boats with slightly more deteriorated or faded gelcoat, a cleaner or restorer wax may be chosen. 3M and others make a good quality product that can be used for this purpose.
For boats that have only minor gelcoat defects or staining, a polish such as Shurhold’s Pro Polish may be used. I have found that polymer polishes work much better than carnuba waxes at sealing the pores in gelcoat and producing a durable high gloss finish. Polymer polishes can last up to a year, while waxes generally only last for a few months at a time.
Wet the microfiber rag and ring it out and then apply approximately a tablespoon of polish to the rag. This amount of polish will work for a few square feet.
Before buffing, spread the polish evenly across the boat’s gelcoat. It is best to work in small areas and work the polish into the surface utilizing a circular motion and lots of leverage. A buffer with wool pad may be used at low speed, but I prefer to buff by hand as it is much more precise and easy to get into nooks and crannies.
When the material dries into a haze, it must be removed with a clean and dry microfiber rag. Be sure to apply adequate force or a film of swirl marks will remain.
Be sure to get in all the nooks and crannies. On my previous boat, there were many and if these are not polished they will be an eyesore.
A note about non-skid: In the past I have cleaned and polished non-skid with polymer polishes like Nu-Finish, which made my deck highly reflective. It did however, make the deck a bit more slippery so I would advise to use a product made for it. Woody Wax makes a good product for this purpose. The best way to polish non-skid is with a wet bristle brush. Simply scrub the polish on and then wipe it off with a dry microfiber towel.
New developments in gelcoat surface protection: for new boats or boats that have been buffed to a deep gloss, a ceramic coating may be a good option. These finishes, usually professionally applied, provide a hard protective shell that lasts for up to a year—or even more.
Method 2: Compound and Polish
For boats 10-20 years old that have been left out in the elements, this is the most likely method for restoring your boat’s appearance. Boats in this category will be oxidized and have many stains. Any striping will likely be heavily faded. While experts may tell you to wet sand your boat with 600-1200 grit depending on the severity of the oxidation, I have found that is both unnecessary and unnerving. Instead, I follow the steps below.
The first step to the restoration of heavily deteriorated gelcoat is to clean the surface. While dish soap or a degreaser may work, it is best to use a pressure washer with moderate pressure and an acid to remove any stubborn and deep staining. For this task, I like On/Off hull cleaner, but hand and eye protection must be worn when dealing with any acidic solution. Other hull cleaners may work as well, but On/Off is the most potent readily available.
Once the hull has been acid washed and pressure cleaned, you will notice it is now clean—albeit dull. A hand buff with a buffing mitt or microfiber towel for heavily oxidized boats is difficult though doable. A rotary buffer wool bonnet is much better. Note: be careful not to burn through the gelcoat by working one spot too long. When buffing be sure to use a good quality rubbing compound and work on small 3-5 ft. sections of the hull at a time. While buffing, the wool pad must be damp.
After working the material into one area, you will notice that the pad is dry and the wool matted. When this occurs, rake the wool back into form with a pad spur and re-wet the pad. It is prudent to change wool pad frequently.
In the past I have had good results with most marine compounds including those offered by 3m and Meguiar’s, but my best results have been achieved with Buff Magic by Shurhold.
After the boat has been compounded to satisfaction, follow up with a polymer polish to chemically seal the now glossy and clean gelcoat.
This process is highlighted above under Method 1, Step 2.
Method 3: Wipe On Acrylic Sealer
While lamenting my old 1987 Ericson 38’s heavily worn and stained gelcoat, I began to research alternatives to painting, which is a highly taxing process. In many spots—especially on our deck—the formerly white gelcoat was worn through, revealing a beige under-layer. Since we were in the midst of a refit and doing the rigging, running rigging, bottom, electronics and more, painting was entirely out of the question. As gelcoat ages, it becomes porous and therefore becomes deeply ingrained with stains. Thus something had to be done about our boat’s ghastly outward appearance which—at a dusty boatyard—acted like a sponge and soaked up any and every contaminant into its large pores. Not wanting to acquiesce, I tried this method as a last ditch effort and so far, it has completely rejuvenated our old gelcoat! If our gelcoat was not so aged and thin, we would have probably tried method 2. If time demonstrates the validity of method 3, we will do it on all of our future boats as it is much easier for large boats than the tedious method 2.
The first step in any gelcoat restoration process is to clean. We did this via pressure washer and an On/Off acid wash to remove embedded stains.
After washing, we bought our supplies. We decided to go with Zep Wet-Look Commercial Floor Polish over the more expensive Poliglow or Wipe New. While you may or may not have better results with one of the more expensive options, we are happy with the cheaper Zep.
While the instructions recommended application via mop, we decided to use terry towels for a more precise application.
After the surface is cleaned and supplies are purchased, it is time to apply. With Zep, four initial coats are recommended, allowing at least 30 minutes of time to dry in the meantime.
Since Zep soaks in to the pores of gelcoat and forms a hard, clear acrylic layer over the gelcoat, prep is vital for satisfactory results! Unlike buffing or polishing—which remove imperfections the more you buff—an acrylic sealer seals in all imperfections so be sure to remove all surface contaminants, bugs and runs before the polish dries or they will be sealed in until the surface is stripped: a tedious process.
Over the course of a few days, we applied four coats to our topsides and hull and were blown away by the results!
To maintain the finish, it is advisable to reapply at least one new coat a year. If you allow this to lapse, the finish will bubble and peel off, making it necessary to strip the whole surface with a proprietary stripper before re-coating. Zep will not make your boat look perfect, but it will breathe new life into ancient gelcoat.
Though the arcylic layer does stain and get scuffed a bit, it usually cleans up with a hose and sponge. The product can be stripped with ammonia and re-applied in problem areas. Next time, we are going to look into the high traffic version of Zep, which has a higher solids content and is more resistant to staining and scuff marks. It requires more coats for a deep shine, but is supposedly easier to maintain. While a proper paint job is looming our horizon, the boat with Zep looks eons better than before and appears clean with a shine.