Hey! It’s time for a quick tutorial on minor gelcoat repair. If you have a hole in your boat, check out my minor hole repair post. I didn’t need to cover that one with gelcoat, but we do have a few spots now that need a little attention!

I love working with epoxy and gelcoat, but I know they can be intimidating! They seem so easy to work with to me because I made a lot of things out of clay when I was young, and those skills come in pretty handy here! Hopefully this post will show you how accessible these repairs can be, especially the little ones.

So we have a few areas of gelcoat that are chipped, including two very visible spots on the nav station. Gelcoat is brittle and easy to chip. There are also a few old screw holes that the previous owners made – it’s important when screwing holes in gelcoat to know how it behaves. If you try to screw something in gelcoat without prepping it, you get big ugly chips. I would recommend making a countersink using a dremel with a grinding tip. Use it on the highest setting, otherwise you get chips. Don’t use the drill, that will cause chips! Ask me how I know…

The first step is to gather everything you need, although you may not need it all today.

Materials

• dremel (optional)
• paper towels
• acetone
• gelcoat and catalyst
• plastic wrap
• drop cloths and/or tape
• paper cups for mixing
• popsicle sticks or something for stirring/applying gelcoat
• kitchen scale
• a block for sanding
• sandpaper in 320, 600 and 1200 grit
• buffing compound
• wax

Steps

1. First you need to prep the area. I use a dremel with a grinding tip on full speed to lightly smooth out the area and create a good surface for adhesion. If you don’t have a dremel you’ll need to sand this down by hand. After that, the dust needs to be cleaned off so that when you apply the gelcoat, you get good adhesion. Use paper towels and acetone to clean the area at least twice, you should be able to rub your finger in the prepped area and see NO gelcoat dust on your fingertip.

2. Now you’re ready to mix up your gelcoat. I rarely shill for any company on this blog, but getting colormatched gelcoat from Fiberlay has turned minor gelcoat repair from an exercise in frustration to a satisfying experience. Seriously. Consider getting colormatched gelcoat, and never waste another drop trying to mix up the perfect color. I had to call Fiberlay, since I didn’t see the option on their website, then we had to send in a 1″ sample of our gelcoat so they could do their superscan to create the match. They had some issues with shipping, but once it was in my hands I was very happy with the product. They offered it with wax and without wax, I chose to get it with wax because then I don’t have to cover the gelcoat with plastic wrap as it cures.

I’ve only ever seen this product from Fiberlay mentioned in like two places on the internet, so if you learn anything today I hope it’s that colormatched gelcoat is easy to get, and totally worth it. We paid $74.49 for 1 qt gelcoat+shipping. At this time, a regular quart of white costs $34, but having tried to mix up color matched gelcoat before I already know I’ll waste at least half of what I mix up!

I make sure there are drop cloths everywhere, since gelcoat is kind of nasty stuff. I also put plastic wrap over my kitchen scale because I seem to always spill a drop as I transfer gelcoat to the cup, and the first time I did this it melted the plastic on my scale a little bit! Mix up the gelcoat per the instructions. Mine is nice because 1 oz takes 14 drops of catalyst. 1 oz is 28 grams, so for every two grams of gelcoat I need one drop of catalyst. I like easy math! Normally I mix up 1/2 an ounce (14 grams). The pot life is about 15 minutes.

3. Stir stir stir the gelcoat. Start dabbing it onto the repair area. It usually doesn’t run too much, but I find that if it does run, I can wait until the gelcoat starts gelling up just a bit so I can really build it up over the repair area. Any extra that you add will mean more sanding later, but if you don’t have enough then you’ll end up with voids and you may have to redo the entire process. So definitely add enough that there are no voids. You’ll also want to try to avoid any air bubbles as you apply it.

4. If you are using gelcoat without wax, you’ll need to place plastic wrap over the gelcoat so that no air is touching it. I find this is a good way to screw everything up, so I made sure to get gelcoat with wax. As it cures, the wax moves to the surface and performs the same function as the plastic wrap.

5. Wait 24 hours for it to cure.

6. Now it’s sanding time! You’ll need a sanding block if you’re working on a flat surface, this will prevent you from sanding a dip into the surface. At this point, you may prefer to tape around the repair area so that when you start sanding the tape, you know it’s time to switch to a higher grit. The tape also helps show where the repair is, because this colormatched gelcoat is so good that I frequently have a hard time finding the spot back.

Grab a cup of water, the 320 grit, and the sanding block and start wet sanding that buildup down. The goal is to only sand the gelcoat you’ve added, and not touch the existing gelcoat, and make sure that sandpaper stays wet. When you get close to the existing gelcoat, it’s time to switch to the 600 grit and continue wet sanding. As you get flush with the original surface, wet sand with 1200 grit to smooth everything out.

7. Clean up the minor gelcoat repair, it should be completely flush with the original surface and have no voids. You’re almost done! It’s time to buff your gelcoat repair, then wax the whole area to protect your handiwork. Finally, it’s time for the cold drink of your choice. You’ve earned it!

It’s really hard to show the repair in these photos since we’re looking at white on white. Our boat is almost 20 years old, we have this fun problem where the very top layer of the gelcoat is a bit yellowed. This means our gelcoat match is actually slightly yellower than the original color, which you only see…when I sand it off. So when I do minor gelcoat repairs, I go in knowing that I’m going to create a slightly whiter spot with a little yellow spot in the middle. You can barely see it in the final photo, but in real life it is only noticeable to me, because I’m a perfectionist, and no one else who comes aboard can spot the gelcoat repairs.

So there it is! Prep the hole, mix the gelcoat, apply it, sand it flush, and enjoy your handiwork!