How to Repair Gelcoat
It is very common for every boat owner to run into an issue with their fiberglass boats. They are often exposed to damage from different circumstances such as poor landings, misplaced drill holes, or dropped fishing equipment. An accident like this can happen to anyone and it will leave scratches or dents on your boat but those can be fixed if you know how to repair Gelcoat damage.
Gelcoat is a polyester resin polymer that is used on a boat's exterior which gives a smooth and shiny look to the fiberglass. The Gel coat also protects the fiberglass boats from water damage and UV damage.
Although Gelcoat is very durable, it can deteriorate as time goes by. Gelcoat can also lose its integrity and durability on speed boats that go really fast, which causes the applied Gelcoat to crack. The Gelcoat can also get damaged by the elements and environment but the biggest threat to it is an impact by some underwater hazard like reefs or rocks.
The tools you will need to repair Gelcoat scratches and any other type of damage to your Gelcoat include:
The first thing you need to do is identify the finish of the boat. If the boat has a painted surface the Gelcoat won’t be able to bond with it. If your boat has a painted surface you will have to remove the paint before applying the Gelcoat. If it already has a Gel coat finish, polyester resin surface, or fiberglass surface you can apply the Gel coat without additional steps before you begin your boat repairs.
Before you start the actual repairs you need to prepare the surface of the repair area. You have to remove the wax using a thinner. If you want to repair a deeper scratch you may need to use 80-grit dry sandpaper for the loose chips which will also help you create a shallow bevel. Afterward, thoroughly clean the surface using acetone.
Related: The Best 5 RV Wax Products
Use paint tape around the damaged area to make sure you protect the surrounding surface and mark the area you are going to work on. Use the tape on any other sensitive surface to make sure it is fully protected by splatter from the Gelcoat. Once you apply the tape, use 360 grit sandpaper to smooth the surface and use acetone to clean it afterward.
If you are fixing a deep scratch on your boat you will need to apply resin and a filler. The filler can be polyester-based or epoxy-based. The epoxy-based filler is better and lasts longer but it is a bit more expensive. Once you have applied the resin and filler, let it dry and then sand the repair before cleaning with acetone again.
Before you apply the Gel coat to your prepared surface you need to match the color of your boat exterior. You can do this either by asking the dealer if they have the same color Gelcoat as your boat or you can get a repair kit that comes with more pigments and try to make the same color yourself. If you can’t find the exact pigment and you are mixing the color alone, do it using natural daylight because it’s much easier to match the shading.
Once you have matched the color you must mix in the catalyst. The ratio of the base and the catalyst is crucial because too much or too little will prevent the Gel coat from becoming fully cured. The correct ratio is usually in the manufacturer’s instructions but if you can’t find it, the most common combination is a two-part ratio.
How you apply the Gelcoat will depend on what type of Gelcoat you are using. If it’s a spray applicator you need to fill the container, attach the hose to an air compressor and apply the Gelcoat with short strokes. When applying the short strokes gradually move outward from the repair area. Leave at least 20 minutes in between applications for the Gelcoat to flash off. You might need to reapply the Gelcoat more than 5 times to achieve a great result.
If you are using a foam brush or a roller to apply the Gel coat you will need to do it in short vertical strokes to get the best result. Make sure you build the Gelcoat slightly higher than the surrounding area so you can sand it down later. Once the Gelcoat is dry use a small amount of PVA curing agent and let it cure entirely.
When the PVA agent is fully cured, remove it and use 320 grit sandpaper and a soft block on the area. Afterward, get 600 grit sandpaper and keep on wet sanding till it’s flush with the area around it. Next, use 1000 grit paper and add a rubbing compound to the area to buff it. Finally, add a wax Gel coating to polish the surface and make it look as good as new.
The damage to the Gel coat on your boat should be taken care of as soon as possible because it may cause water damage to the fiberglass frame of the boat. It can also corrode the metal parts of your boat that are protected by the Gel coat and create a much bigger problem that is more expensive to fix. If you know how to repair Gelcoat on your boat and you fix it often you will prevent any potential damage to the fiberglass structure and metal components of the boat. This way you will make sure your boat is in perfect shape and you are completely safe on the water.
What Is Gelcoat?
Gelcoat is a polyester resin polymer that is used on a boat's exterior which gives a smooth and shiny look to the fiberglass. The Gel coat also protects the fiberglass boats from water damage and UV damage.
Although Gelcoat is very durable, it can deteriorate as time goes by. Gelcoat can also lose its integrity and durability on speed boats that go really fast, which causes the applied Gelcoat to crack. The Gelcoat can also get damaged by the elements and environment but the biggest threat to it is an impact by some underwater hazard like reefs or rocks.
What You Need To Repair Gelcoat
The tools you will need to repair Gelcoat scratches and any other type of damage to your Gelcoat include:
- Latex gloves
- Respirator
- Mixing cups and sticks
- Plastic spreader
- Dremel tool with a burr-type bit
- Masking tape
- Acetone
- Plastic sheet
- Waterproof abrasive paper with various grits (180 to 400)
- Paper towels
- Sanding block
- Gelcoat
- Compound and polish
- Clean lint-free rags
Identify the Finish of the Boat
The first thing you need to do is identify the finish of the boat. If the boat has a painted surface the Gelcoat won’t be able to bond with it. If your boat has a painted surface you will have to remove the paint before applying the Gelcoat. If it already has a Gel coat finish, polyester resin surface, or fiberglass surface you can apply the Gel coat without additional steps before you begin your boat repairs.
Prepare the Surface
Before you start the actual repairs you need to prepare the surface of the repair area. You have to remove the wax using a thinner. If you want to repair a deeper scratch you may need to use 80-grit dry sandpaper for the loose chips which will also help you create a shallow bevel. Afterward, thoroughly clean the surface using acetone.
Related: The Best 5 RV Wax Products
Use Tape On The Area
Use paint tape around the damaged area to make sure you protect the surrounding surface and mark the area you are going to work on. Use the tape on any other sensitive surface to make sure it is fully protected by splatter from the Gelcoat. Once you apply the tape, use 360 grit sandpaper to smooth the surface and use acetone to clean it afterward.
Use The Filler
If you are fixing a deep scratch on your boat you will need to apply resin and a filler. The filler can be polyester-based or epoxy-based. The epoxy-based filler is better and lasts longer but it is a bit more expensive. Once you have applied the resin and filler, let it dry and then sand the repair before cleaning with acetone again.
Match The Color
Before you apply the Gel coat to your prepared surface you need to match the color of your boat exterior. You can do this either by asking the dealer if they have the same color Gelcoat as your boat or you can get a repair kit that comes with more pigments and try to make the same color yourself. If you can’t find the exact pigment and you are mixing the color alone, do it using natural daylight because it’s much easier to match the shading.
Add The Catalyst
Once you have matched the color you must mix in the catalyst. The ratio of the base and the catalyst is crucial because too much or too little will prevent the Gel coat from becoming fully cured. The correct ratio is usually in the manufacturer’s instructions but if you can’t find it, the most common combination is a two-part ratio.
Apply The Gelcoat
How you apply the Gelcoat will depend on what type of Gelcoat you are using. If it’s a spray applicator you need to fill the container, attach the hose to an air compressor and apply the Gelcoat with short strokes. When applying the short strokes gradually move outward from the repair area. Leave at least 20 minutes in between applications for the Gelcoat to flash off. You might need to reapply the Gelcoat more than 5 times to achieve a great result.
If you are using a foam brush or a roller to apply the Gel coat you will need to do it in short vertical strokes to get the best result. Make sure you build the Gelcoat slightly higher than the surrounding area so you can sand it down later. Once the Gelcoat is dry use a small amount of PVA curing agent and let it cure entirely.
Use Sandpaper
When the PVA agent is fully cured, remove it and use 320 grit sandpaper and a soft block on the area. Afterward, get 600 grit sandpaper and keep on wet sanding till it’s flush with the area around it. Next, use 1000 grit paper and add a rubbing compound to the area to buff it. Finally, add a wax Gel coating to polish the surface and make it look as good as new.
The damage to the Gel coat on your boat should be taken care of as soon as possible because it may cause water damage to the fiberglass frame of the boat. It can also corrode the metal parts of your boat that are protected by the Gel coat and create a much bigger problem that is more expensive to fix. If you know how to repair Gelcoat on your boat and you fix it often you will prevent any potential damage to the fiberglass structure and metal components of the boat. This way you will make sure your boat is in perfect shape and you are completely safe on the water.
