A man works on re-painting his boat hull.

A Boat Repair Guide To Painting Over Gelcoat

A Boat Repair Guide To Painting Over Gel Coat (aka Gelcoat)
Paint is an essential part of boat repair, enhancing the overall look and helping seal the hull. Painting over the gel coat is good because the gelcoat acts as an adhesive for the paint to stay on the place. However, you will have to inspect the condition of the gel coat before proceeding.
The process of painting the boat depends on the gel coat’s condition. If the gel coat is wearing off, it must be taken care of first. In the worst-case scenario, the gel-coat might need removal to apply a fresh layer.
This article is the ultimate boat repair guide, so all those who’re looking forward to painting their boats over the gel coat should follow it until the end. It talks about the essentials of boat repairing (in terms of painting).
How To Paint The Boat Hull – Over Gelcoat?
Let’s quickly get started discussing painting the boat over a gel coat. As stated before, after inspecting the gel coat’s condition, the painting process might vary. So we’ll cover the most common conditions in this section.
The following are the possibilities, which can affect the entire painting process. i) If the gel coat isn’t chalky and or doesn’t seem to be damaged ii,) gel coat shows signs of wear and tear (might become chalky).
How To Prepare The Gelcoat?
It’s good to know well in advance how much gelcoat you might need. This part is optional if the repair work doesn’t require a gel coat application at all.
A 14 feet hull can be covered with one-quarter of gelcoat at a 0.254mm to 0.381mm thickness. It’s a general rule that the gelcoat preparations occur in batches of 5 ounces.
After the gel preparation, you’ll have around 15 to 20 minutes to apply it on the boat. So, making more than 5 ounces would put all the extra gelcoat in peril, wasting your efforts and materials.

Steps To Paint The Boat

If the Gelcoat Is Good

This section assumes that the gelcoat seems fair and doesn’t need scraping or grinding off.
Look for the damages on the boat. Some minor cracks might exist. Fix them before proceeding.
If the gelcoat seems to be dewaxed, go for it. Clean it thoroughly. Skip this step if it seems fair.
Take sandpaper. 400-grit sandpaper would be good enough. Wet sand the area that you need to paint. It will roughen up the gel coat’s surface, and the paint will stay on place.
Mask the areas which you won’t be painting. It’s best to use masking tape along with a bunch of newspapers. Apply the tape on the areas not to be painted so that half of the tape is on the boat and the remaining is on the newspaper.
For the painting part, you can either go with the traditional brush painting or the spray gun. If using the spray gun, hold it 8 to 15 inches away from the surface (or closer if needed, based on the spray gun range).

If The Gelcoat is Bad

Now we’ll take a look at the steps assuming that the gelcoat is all messed up. You will have to go through additional steps to repair the gelcoat. Generally, the majority of people first go for repairing the hull and then for the deck. But that’s not compulsory at all.
Dilute the marine soap in water and wash the surface with it. The use of marine soap is positively encouraged more so than ordinary dishwashing liquids since it’s eco-friendly and designed for the job.
Once the dirt is off, inspect for any damages on the boat. Look for minor cracks, holes, etc. Fix the issues (if any) before proceeding any further.
Remove the gelcoat stains. There’s a high chance that your boat will have some leftover stains because washing merely with the soap water isn’t 100% effective. You can find a decent acid-based stain remover like this one found at Amazon, which is super easy to use.
Remove the oxidation. If the gelcoat has a chalk-like powdery look, it’s more likely to be highly oxidized. Polishes find use if the oxidization level is low, whereas a rubbing compound is best if the boat surface is highly oxidized.
Now apply the gelcoat once you get a shiny surface after taking care of oxidization.
Follow steps 4 and 5 from the above section to start painting your boat.

Finishing Steps

When complete with the painting, let it dry thoroughly. Remove the masking tape and the newspaper gently by pulling it downwards (or against the surface) at an angle of 45 degrees. Make sure to be gentle as you would not want to remove any paint coating accidentally.
If you notice that the paint color is duller than expected, here’s a quick and straightforward solution. Apply wax! The wax will act as a polishing agent, which leaves a shiny surface. The wax application removes a microscopic layer of the paint, but that’s always negligible.
Some Precautions And Important Points To Ponder
There are a few points you must take care of when repairing your boat. These include:
Unprotected gelcoat is highly vulnerable to oxidation. Protect your gelcoat surface by applying a wax layer on top of that. It’ll help gelcoat stay like new for years or maybe decades.
Gelcoats don’t wear off quickly. Not even after using the boat for decades. So make sure to inspect the boat thoroughly before deciding to scrape off the gel coat.
You can use the chelating non-skid cleaners to break the bond between the dirt and the boat’s surface and avoid heavy scrubbing.
Acid-based stain removers come in the form of a gel, which makes it super easy to apply. It requires little to no rubbing.
MAKE SURE to wear eye protectors and rubber gloves while working with the acid-based stain remover.


Keep the stain remover away from painted and galvanized surfaces, as the acid will depreciate them.
Use a good quality polish if the gel coat isn’t highly oxidized. Using the polish on a messed up gel coat won’t be effective.
On the other hand, rubbing compound can take off oxidation easily without rubbing too hard. So make sure not to put in too much strength because that might damage the boat’s surface.
Make sure to do the repairs in a well-ventilated area. Most probably, in an open space on a clear and warm day.
What if The Paint Bubbles Or Wrinkles Up?
You might notice that some painted part starts to bubble up or wrinkle up. To overcome this mess, follow the steps below:
First of all, stop painting immediately. Let that part dry, and then dry sand the area.
Wax the surface and let it dry again.
Mask this area to avoid repainting or uneven painting. Now resume painting the boat. When I finished painting all the parts, take off the mask. The wax allows peeling the tape without messing with anything again.
Finally, when done with the entire boat, peel the mask gently.
Additional Measures
During the boat repairing, you might like to follow these additional measures. It’s totally up to you to go for that or ignore it if the situation isn’t favorable.
Strip all the hardware. It’s effortless to accidentally paint or wax the installed hardware, which might damage your stuff. However, stripping all of the hardware and reinstallation would be more than a little troublesome.
If the surface isn’t too bad, perhaps you can wet sand it. Then apply a polish compound, gel, and finally, the paint. It can help you save weight.
Go for spray paints since it’s quick and easy to apply.

The Final Word On Painting Over Gelcoat

It’s safe to conclude that painting your boat can be troublesome if the gel coat is all messed up. So make sure to keep the gel coat as safe as possible. That way, you have to paint your boat from that point forward. We’ve talked about the safety measures, essential points, and procedure to paint your boat thoroughly. A well-repaired boat (gel coat + paint) can live for decades, so try not to be stingy during the repair works.

Gel Coat FAQ

Sources

  1. https://www.sailnet.com/threads/painting-right-over-gelcoat-no-sanding-necessary.98360/
  2. https://forums.paddling.com/t/painting-over-gelcoat/58879
  3. https://www.offshoreonly.com/forums/fiberglass-paint/133342-painting-over-gelcoat.html
  4. https://goneoutdoors.com/paint-over-gelcoat-boat-5143006.html
  5. https://www.westmarine.com/WestAdvisor/Gelcoat-Care-and-Restoration
  6. https://betterboat.com/spraying-gelcoat/

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