For most of a boat’s life, its gelcoat will survive if taken care of. However, occasionally you become the caretaker of a fiberglass boat that has been neglected or that is too old, and the gelcoat has worn thin.
If the gelcoat can’t be saved, you have a choice to make. Do you replace the gelcoat? It’s a big and expensive project, but the boat will be good to go for another few decades. Or do you opt for paint, a less expensive and more straightforward option?
Table of Contents
- Gel Coat Boat Repair vs a Paint Job
- How to Paint Gelcoat
- Restoring the Original Finish Instead of Painting Over Gelcoat
- How to Paint Over Gelcoat
- Can I Paint Over Gelcoat?
- FAQs (Frequently Asked Questions)
Gel Coat Boat Repair vs a Paint Job
When the outer finish of your boat starts to fade, the gelcoat will start getting darker as the laminates below show through. The first thing you must determine is whether or not the boat has any existing paint. If it has old paint, your choices are limited—you probably ought to repaint it. You could strip it back to raw paint fiberglass and start again with gelcoat repair kits, but the prep work required would likely mean it wasn’t worth the trouble.
For the rest of us, the choice is always between another coat of gelcoat or a coat of paint. Both have pluses and minuses. In a perfect world, gelcoat repair kits would always be the correct answer. But the main detractor for that option is the cost to gelcoat a boat—not to mention the difficulty of dealing with gelcoat.
If you’re paying professionals and helpers, neither option is inexpensive. As with all paint jobs—be it houses, furniture, cars, or anything else—the quality of the ultimate finish comes down to the amount of preparation you put in.
So the ultimate cost of doing either job comes down to how many hours of preparation the hull needs. If you’re refinishing the deck of the boat, there’s probably a lot of hardware you’ll want to take off, clean up, and re-bed.
How to Paint Gelcoat
Gelcoat is a plastic resin, just like the rest of the paint fiberglass that makes up the boat. When people talk about painting on gelcoat, they usually mean making small patches and fixes into the existing finish. In other words, gelcoat is easy to boat repair but not so easy to replace.
Painting gel coat is very similar to painting on an epoxy barrier coat. It is a two-part product that you mix. It has a limited pot life and is very sensitive to temperatures. So it can’t be too hot or too cold when applying, and you’ll also want to watch the humidity level.
While it is possible to paint gelcoat on with a brush or roller, the best results are achieved with a spray. And unless you’re covering a minimal area, professional spray gun applicators are usually out of the reach of most DIYers.
Perhaps the most challenging thing about gelcoat is getting a good color match. It is pigment-based, and as a result, you can make it any color. But finding the right match is complex, and you’ll often wind up playing with it and going through a lot of trial and error.
Restoring the Original Finish Instead of Painting Over Gelcoat
A boat finish that is dry, chalky, and faded can look terrible. But the good news is, it might not need to be gel coated or painted—you might be able to restore faded boat gelcoat stains. Gelcoat wears down over time and gets oxidized. It also absorbs a lot of nastiness from grime, saltwater, and pollution.
The solution is called compounding. A compound is a gritty wax, much like a polishing or rubbing compound used to buff out scratches on a car. Compounding the boat will grind off the oxidization and dirty layers when applied with a machine applicator.
Start with a clean hull because the last thing you want to do is introduce scratches from dirt. Apply the compound over the hull evenly, working in small sections. Then, using a power buffer, polish it off just like you would a regular wax.
Depending on the severity of the oxidization, you might have to do the compounding a few times. You can also pick the level of polish you need from your compound. Some are sold for maintenance and annual use, while others are grittier and specifically for restorations.
If the compound doesn’t do the trick, you can resort to wet sanding the gelcoat to bring out its shine. All of these techniques are rubbing off more gelcoat, so you can’t keep doing them forever. When the gelcoat gets thin, you’ll have to add more or paint.
Once you’ve compounded the boat back to its factory shine, be sure to follow up with a high-quality marine paste wax. This will seal the gelcoat and keep grime out and oxidization at bay.
How to Paint Over Gelcoat
When all else fails, it might be time to go ahead and paint it. You might be painting small patches, or you might be refinishing the entire hull or deck.
Your preparation will depend a lot on the type of paint you use. Will automotive paint stick? Can you paint over gelcoat with house paint? For all of these questions, many sailors have tried.
I can’t see the advantage of gaming the system. A five-gallon tub of outdoor paint from a big-box hardware store might be cheaper but would likely have to be reapplied more often. Regardless, it’s doubtful that you’d get the same shine that the marine polyurethanes produce.
Automotive paints are designed to be sprayed over metal using a spray gun. So if you’re looking for something to stick to gelcoat, they might work—but then, they might not. Either way, you’re unlikely to be saving much money, if any, compared to a yacht finish.
The point is that there are plenty of companies making excellent topside finishes for boats. The ones that are DIY-friendly are easy and reliable to apply and produce beautiful results. A few of the companies to look into include TotalBoat from Jamestown Distributors, Petit, and Interlux.
The benefit of using these marine paint products comes from their availability at marine suppliers and their support and knowledge bases. If you’re wondering how to paint a boat with gelcoat, these companies have every answer you need to paint your boat like a pro.
The first step of the process is the hardest. Getting your boat ready to be painted is no simple matter.
For the best results, you’ll want to remove all hardware. You could mask and paint around everything, but this won’t produce perfect results. Most owners wind up painting around something things and removing and painting under other things.
If you’re painting the deck, there is a lot of hardware to consider. And of course, getting access to through bolts and taking things off is no simple matter. Here are just some of the items you’ll have to consider.
- Docking hardware like hawseholes and cleats
- Sailing rigging hardware like traveler tracks and jib car tracks
- Anchoring hardware like windlasses, chocks, rollers, and cleats
- Handrails, grabrails, and station bases
Once the area to be refinished is cleared, you’ll have to do some gelcoat surface preparation. Any wax built up will need to be removed with grease remover before you apply primer. You’ll also need to do some light sanding, and then, of course, you’ll have to remove all residue from that process. The surface needs to be perfectly clean before you apply anything.
This also assumes that there’s nothing wrong with the surface in question. There will usually be some issues to work out before painting. If there are any cosmetic or structural issues with the fiberglass, fix them now. Likewise, if there have been leaks and you need to fix any part of the core, it’s best to take care of it before painting.
There are always minor chips and major cracking in the gelcoat that should be tended, and you also need to be looking out for potential stress cracks. Since you’re painting over the entire gelcoat surface, you don’t have to worry about cosmetics. You can use an epoxy filler – just ensure that it bonds well, sets completely, and sands down perfectly fair.
When the surface of the boat repair is completed and as smooth and clean as possible, a gelcoat epoxy primer is applied. These are usually epoxy-based, but whatever you use should be from the same paint system as your topcoat. Again, it’s not worth mixing and matching for the best price here. It’s far better to spend a few extra dollars if you have to and use the product you know will work.
The purpose of applying the epoxy primer layer is two-fold. First, it helps fair the gel coat’s surface and fill in any minor imperfections. But it also provides a better bond between the old gelcoat and the final topcoat finish.
The damp epoxy primer can be sprayed, rolled, or painted on with a brush. The key, though, is to get it as even and level as possible. It might require two or three coats of primer to get the best results. Lightly sand between coats and remove all sanding residue.
The primer will be allowed to cure and then sanded down for the final paint job. Any imperfections in the finish coat should be sorted out before the final layers go on.
Topcoat Paint Over Gelcoat
Finally, your top coat finish will go on. The goal of this layer is to provide a hard-wearing and shiny finish, so you want it to go on evenly and smoothly. You could spray it, but the roll and tip method are far more manageable. Spray paints are harder to apply and require a protected area to get that perfect shiny surface.
The top coats you choose will have a significant effect on your process. Follow the manufacturer’s instructions in the letter, especially concerning drying times, working times, and temperatures. If it says to sand it, sand it with precisely the grits they specify.
Topcoats will be either one or two parts. Two-part epoxy paint coatings are harder and may last a little longer, but they’re also harder to deal with during the application process.
Can I Paint Over Gelcoat?
Paint jobs aren’t very complicated, and many owners paint their boats often with excellent results. In the end, it’s just a process of buying the right products and following the instructions perfectly. If you care about the quality of the final job, don’t skimp on the product, and don’t take shortcuts or try to save time.
FAQs (Frequently Asked Questions)
Do I need to prime gelcoat before painting?
If the gelcoat is in good condition and prepped correctly, you don’t need a primer coat. But it’s a good idea because it will help the paint stick better and will provide a better overall finish. In the end, the best course of action is to follow the paint manufacturer’s instructions for painting over gelcoat. Then, use the products and procedures they specify for the best results.
Will automotive paint stick to gelcoat?
Automotive paint might stick to gelcoat, but it’s not the best solution. Generally, car paints are designed to be sprayed onto hard and non-porous surfaces in extremely thin coats. A better choice would be polyurethane yacht coatings, which can be rolled and tipped onto fiberglass vessels. They’re available in a wide range of color and finish options and will last many years if applied as directed.