Let’s say that the gelcoat on your boat looks less than stellar—as in chalky like a chalkboard less than stellar. Maybe your blue boat now has a purplish hue, or your topsides don’t reflect anything other than poor care. The good news is that the damage is reversible, in most cases. The bad news is that you have a lot of work ahead of you.
Whether you’re trying to prep your boat for sale or rehabbing a new acquisition, or just sprucing up your current ride, restoring gelcoat shine not only makes you feel better, it actually enhances the value of your boat and helps to make it last longer. It’s also one of the easiest things (from a technical standpoint) you can do on your boat yourself.
You might have a lot of folks tell you that you can get away with using one-step waxes and snake-oil treatments that guarantee a great shine, but the truth is, if you have a badly oxidized gelcoat finish, the method you’re going to read about here is exactly how the pros would do it if you hired the job out yourself. It requires some specialized tools and materials, but you can save a good amount of money doing it yourself. If you have light or moderately oxidized gelcoat, have a look at this video, which explains the steps in removing that light oxidation from your boat.
Tools of the Trade
The first step in any gelcoat restoration job is removing that layer of oxidation standing between you and a good shine. And if that oxidation is heavy, I’m not going to lie to you—only a machine will get it off. You can use a household electric drill with a retrofit buffing pad if yours is a small project, but if you need to compound anything over 20 feet, a seven-inch angle grinder with the correct buffing pad (3M’s Superbuff is a good one to try) is the tool to get. Expect to pay around $200 for a good-quality one, or you can also usually rent them for around $30 a day from a tool rental shop.
Before we get started, we’ll assume your boat is out of the water or on a trailer, because it’s virtually impossible to restore a faded gelcoat hull while a boat is in the water. (If you’re just working on the decks and interior portions of your boat, you can certainly accomplish that while the boat is floating.)
First, give whatever gelcoat surface you’ll be compounding a good wash, and then let it dry. If it’s especially dirty, use a heavy-duty cleaner such as Krazy-Klean or On and Off. Once you’ve gotten the dirt out of the way, it’s time to break out the rubbing compound and machinery.
The first step in the process involves using rubbing compound, which is generally a mineral-spirits based liquid or paste with fine abrasive particles suspended in it. When you “rub” in a rubbing compound (or polish it in with a machine), it slowly removes all of that nasty gelcoat oxidation from the surface. Do it long enough and you polish in a dull shine. The objective in this step is not to get a high-gloss shine, but to remove all of the oxidization and prep the surface for a finer polishing. Now, if your gelcoat is scratched or gouged, you’ll want to make those repairs before getting started.
The key when compounding is to not to fling compound all over your boat or your neighbor’s boat when you fire up the grinder or drill. The way I accomplish this is by not applying the rubbing compound to the buffing pad, but to the gelcoat itself first. You can accomplish this by loading a small amount of compound onto a rag and then smearing it into a workable area of gelcoat.
Next, work the compound in with the machine at slow speed, and in short bursts, to avoid overheating the pad. Work back and forth in a small area until you feel as if you’ve given equal treatment to the entire surface. As the compound dries, you can wipe it off with rags as you go along, repeating the compounding until you feel as if you have all of the oxidation removed. Working in small areas is key. The hull won’t shine like a new penny at this point, but it shouldn’t have any hazy spots, either.
After you feel like you have the oxidation dealt with, it’s time to actually polish the surface to a glossy shine. That’s where 3M’s Perfect-It Machine Polish comes in. This material contains abrasives like the rubbing compound does, but they’re much finer, meaning that they’ll deal with any swirl marks left behind by the compounding, and bring the shine level way up. Apply it and work it in exactly like you did with the rubbing compound. Repeat as necessary in areas where the shine doesn’t fully come up.
If you’re really a glutton for punishment, you can finish this step off by going over the entire surface with 3M’s Finesse-It polish, which has an even finer level of abrasive content in it. As with the other materials, apply it and work it in, repeating as necessary in areas where the shine doesn’t fully break through.
Wax On, Wax Off
The last step in your gelcoat recovery is probably the most satisfying. Now’s the time to apply good liquid or paste wax that will bring up that final high-level shine and protect your gelcoat from dirt, salt, and sun. I like Star Brite’s Premium Marine Polish with PTEF or 3M’s Ultra Performance Paste Wax, but use your favorite, if you have one. Or, check out some of our recommendations in this handy article on waxes and polishes.
It’s always better to apply wax in thin coats versus applying one thick globby one, and you should apply at least two coats to last a season. Yes, I know, at this point you’re pretty exhausted with this process, but the better this last coat of wax, the longer that nice new shine you’ve worked so hard for will last. Use a clean rag or foam applicator (available at most marine or auto shops) to apply a thin glaze of wax to the surface, and then wipe it off once it has dried. Repeat until your arms fall off. It’s that easy.
Voila! At this point you should have a glossy, durable shine that will make you the envy of your local waterways. To keep it up over the years, apply a couple coats of good-quality wax once or twice a season to keep that new-boat shine.