Painting A Sailboat with 100% Acrylic Paint

[Seahorse24]

We purchased a forty-year 24 foot sailboat and are in the process of restoring it.

My son and I have painted the sides and topsides of our sailboat with 100 percent Acrylic Exterior House paint. The improvements in Exterior Latex House paint over the years has resulted in a highly durable finish that can stand up to both sunlight and water. We are confident the Acrylic paint will hold up on the top and sides. The previous owner had applied house paint to the top side nine years ago and it was in fairly good shape except for a few areas where he had not properly cleaned the surface area prior to applying the new paint.

We sanded the top and sides, and then applied a primer, also 100% Acrylic. The following day, we applied two coats of 100% Acrylic exterior house paint. The paint flowed easily and went on without a hitch. We used anti-slid porch paint, also 100 percent Acrylic, on the walk ways on the top side. It has a tan color. Before and after photos attached.

Our biggest challenge appears to be painting the bottom:

We plan to use CM-15 epoxy for the barrier coats. We expect to apply at least two barrier coats and maybe three over the existing barrier coat that was applied nine years ago. The anti-fouling paint was removed, and we are down to the existing barrier coat. We do not want to use anti-fouling paint for our application.

What we are debating is what to use for top coating the CM-15 epoxy. This boat will be stored on a modified lift and will be out of the water whenever we are not sailing. My son has used tractor-grade enamel on a flat bottom metal boat and it has held up very well for that application, but that paint requires a respirator to apply.

After running my own tests on 100 percent Acrylic paints, I am seriously considering top coating the barrier coat with Acrylic paint, because it is so easy to use and less than forty dollars per gallon.

Samples, that I left submerged in water for weeks, showed no loosing or peeling of paint whatsoever. It was as if the paint had never been under water. The paint I applied to the top and sides uses nano-technology to bind the molecules during the drying process. The dried coating is water tight and keeps water from penetrating the layers of paint. It appears, unless the paint is scratched, water cannot get to the wood or fiberglass surface at all.

If I were going to use this boat on the ocean for long periods of time, I would not consider Acrylic paint for the bottom, but since this boat will live in fresh water and be on a lift a good part of the time, it sure would be easier to do touch ups or repaint if necessary with the Acrylic paint. You can scratch the Acrylic paint, if you apply pressure using the edge of a rock, but a fingernail won't phase it.

Has anyone tried using 100 percent Acrylic paint for bottom paint on a sailboat? If so, what were your results? My son wants me to get additional opinions before we go that route.

 

[31seahorse]

"You can scratch the Acrylic paint, if you apply pressure using the edge of a rock, but a fingernail won't phase it."

I have ALWAYS tried to avoid getting our boats near to the edge of a rock, so if that is the test you are using the paint should be fine!

Your second picture shows a job nicely done on the deck, and if it lasts well you should be happy with it. There are several marine paints specifically for below the waterline. You could search (google) paint tests for some results.

 

[Don S/V ILLusion]

Maybe I don't understand, however, it sounds to me you are looking for a solution to a problem that doesn't exist.

If the boat isn't being stored in the water and the gelcoat hasn't been compromised, what is the point of the paint?

 

[agprice22]

Acrylic paint will blister and peel if it sits under water. I realize you did not paint below the waterline, but sometimes the line ain't so clear. I painted the top half of my rudder with acrylic, and the waterline was a little highter than I thought, so a couple inches of the acrylic ended up under water. It bubbled in less than a week. Oh well.

Thanks,

Andrew

 

[Seahorse24]

31seahorse, I will look at what's available in marine paint before I make a final decision.

 

[Seahorse24]

Maybe I don't understand, however, it sounds to me you are looking for a solution to a problem that doesn't exist.

If the boat isn't being stored in the water and the gelcoat hasn't been compromised, what is the point of the paint?

I wish the boat had a gelcoat, because you're correct.

Don S/V ILLusion, there is no gel coat that I can tell. We are down to the previous barrier coat that was applied nine years ago. After we repair a few blisters, we are going to apply at least two coats of CM-15 over the existing barrier coat and then cover the CM-15 so the ultraviolet Rays of the sun won't damage the new expoxy coating. The new epoxy coating is needed to form a new barrier coat. The only purpose of the final paint coat on the bottom is to Block sunlight directly on the CM-15 epoxy when the boat is on the lift.

If we were not going to store the boat on a lift, the CM-15 would not need protection from the sunlight.

 

[Seahorse24]

Acrylic paint will blister and peel if it sits under water. I realize you did not paint below the waterline, but sometimes the line ain't so clear. I painted the top half of my rudder with acrylic, and the waterline was a little highter than I thought, so a couple inches of the acrylic ended up under water. It bubbled in less than a week. Oh well.

Thanks,

Andrew

Andrew, thank you for letting me know your experience with using Acrylic paint below the waterline.

If the bottom was not so difficult to get to, I might be tempted to still try it with the paint I tested. But based on your experience, I will probably go with a marine paint and leave experimentation to a small boat we can flip over easily.

Here is why I thought it might work.

I had to paint my front door last year. I had a paint brush that dried for two hours, after I forgot to clean it. I was unable to get any of the Acrylic paint off of it by soaking it in water. That $12.00 brush was in water for two months and the water never tinted nor did any paint ever loosen on the brush. I had to throw the brush in the trash. That is when I said, this is what I am going to use on the top and sides of the sailboat. I then did small test samples on wood, which remained submerged in jars of water for months. Same result, but it's not worth the risk on the sailboat bottom, after learning about the peeling you witnessed on your rudder.

Our rudder pulls out from the top and we could get to it easily. I might try painting one side of the rudder with Acrylic and the other side with whatever marine paint we end up using on the bottom. I could report the status in a post next year after some actual sailing time in the water. At the same time, I could report on how the top and sides are holding up.

 

[Brian S]

Seahorse, you say there isn't any gelcoat, down to the previous barrier coat from 9 years ago.

If this is so, you'd see translucent dark resin with some glass in it. Gel coat sits on top of the laminate resin, and barrier coat is often applied over the gelcoat. And then, for bottoms, generally some form of antifouling paint. Earlier gelcoat formulations could blister, osmotic blisters, and barrier coat was intended to prevent water getting to the gelcoat and causing the blisters.

If, as you say, you are down to barrier coat, then under that, there ought to be gelcoat, unless someone had sanded all the gelcoat off (maybe to cure a really bad case of pox?) and then barrier coated right on the laminate.

 

[Brian S]

Oh, BTW, TSBB2 swears by acrylic latex paint for the interiors of boats. As long as it's ACRYLIC latex.

 

[Chief RA]

The commercial fishermen in Bodega Bay say to mix cayanne pepper with your bottom paint to oppose growth on the bottom! Chief

 

[Ray Bowles]

I've got a 1982 San Juan 23 that has been stored rigged on the trailer and launched to sail, always in fresh water. I lower the mast for winter and cover with tarps. It has never been painted anywhere in its' life. I, and the previous owners have waxed it every year. It does go on trips of up to 1 month and spends weekends in the water. She looks like new.
If you plan to sail the same way/style then painting is not required. Waxing is.
Ray

 

[Seahorse24]

Seahorse, you say there isn't any gelcoat, down to the previous barrier coat from 9 years ago.

If this is so, you'd see translucent dark resin with some glass in it. Gel coat sits on top of the laminate resin, and barrier coat is often applied over the gelcoat. And then, for bottoms, generally some form of antifouling paint. Earlier gelcoat formulations could blister, osmotic blisters, and barrier coat was intended to prevent water getting to the gelcoat and causing the blisters.

If, as you say, you are down to barrier coat, then under that, there ought to be gelcoat, unless someone had sanded all the gelcoat off (maybe to cure a really bad case of pox?) and then barrier coated right on the laminate.

Brian, I don't really know if there is gelcoat under the gray barrier coat. The previous owner had the bottom repainted nine years ago. He told us they did two layers of barrier coating and two layers of anti-fouling paint. The boat then sat in the water for seven years. My son and I purchased it two years ago and placed it in dry dock on the trailer. We did not begin restoration on it until this summer. This is our first sailboat so we are learning as we go.

There are a couple of small dark stains that appear near the water line near the back of the boat on the gray barrier layer from time to time. We scrubbed it off with soap and water, but after a few weeks a little of the stain comes back in a small area. We don't know what that is.

There were three large blisters the size of quarters. We repaired those. The small blisters receded after the boat sat on the trailer for a year., and the bottom is now pretty smooth. That is why we plan to add at least two new barrier coats using CM-15 two part epoxy.

We have a 3000 PSI power washer that we used to clean the boat before we started sanding. To test the new Acrylic paint, I set the sprayer for 2000 PSI and blasted a square foot area on the painted hull for two minutes. None of the new Acrylic paint came off. I could not see any damage to the painted area.

 

[Don S/V ILLusion]

Every boat has a gelcoat layer covering the glass. Unless the poster removed it intentionally or otherwise, there is no problem here to fix.

 

[agprice22]

Andrew, thank you for letting me know your experience with using Acrylic paint below the waterline. If the bottom was not so difficult to get to, I might be tempted to still try it with the paint I tested. But based on your experience, I will probably go with a marine paint and leave experimentation to a small boat we can flip over easily. Here is why I thought it might work. I had to paint my front door last year. I had a paint brush that dried for two hours, after I forgot to clean it. I was unable to get any of the Acrylic paint off of it by soaking it in water. That $12.00 brush was in water for two months and the water never tinted nor did any paint ever loosen on the brush. I had to throw the brush in the trash. That is when I said, this is what I am going to use on the top and sides of the sailboat. I then did small test samples on wood, which remained submerged in jars of water for months. Same result, but it's not worth the risk on the sailboat bottom, after learning about the peeling you witnessed on your rudder. Our rudder pulls out from the top and we could get to it easily. I might try painting one side of the rudder with Acrylic and the other side with whatever marine paint we end up using on the bottom. I could report the status in a post next year after some actual sailing time in the water. At the same time, I could report on how the top and sides are holding up.

Cool. The way I see it, you could give it a try on a smaller scale. The rudder seems a good place to try. I wish I could roll my boat over too! Haha... It is 27 ft long and weighs over 5000 lbs. The problem with a large scale test is the large scale repair that may follow. My decks are patterned with non-skid, so removing a peeling paint would be a tremendous effort.

Thanks, and don't worry too much about trying new stuff... It shows the rest of us new ways to do old stuff.

Andrew

 

[Seahorse24]

I've got a 1982 San Juan 23 that has been stored rigged on the trailer and launched to sail, always in fresh water. I lower the mast for winter and cover with tarps. It has never been painted anywhere in its' life. I, and the previous owners have waxed it every year. It does go on trips of up to 1 month and spends weekends in the water. She looks like new.
If you plan to sail the same way/style then painting is not required. Waxing is.
Ray

Thank you for your response, Ray. I don't think the bottom of our sailboat is at a point where we could wax it. We need to work on it bit more.

 

[Seahorse24]

Here is the latest photo of our bottom paint progress as of August 2015.

After we had all of the old blue ablative paint removed, we wet sanded the existing barrier coat. We used an air-powered sander to grind out the blisters we found. Only one had moisture behind it. The boat had been in dry dock for two years. We applied a coat of no-blush epoxy over all of the blisters.

We then applied three new barrier coats of CM-15 two-part epoxy. Our first application still was not completely dry after five days in 90 degree heat. That problem and our resolution is detailed in another post. After our third barrier coat application, we were able to apply a coat of 100 percent acrylic latex primer. The photo attached shows the bottom with the coat of Latex paint.

Since we plan to keep the sailboat on a freshwater lake and stored on a boat lift when not in use, latex paint should work fine. We have a blog of our boat restoration process and will maintain records of how well the latex holds up in our application.

 

[Capt jgw]

One of the passenger boats I ran, the owners insisted on painting with acrylic. It was cheap, easy, and looked good for a couple years, bit we were recoating every couple years to keep it looking good. And being a dinner boat it had to look good. And forget about sanding it off . It just clogs the paper. If they'd used a proper oil enamel, even a cheap one like Rustoleum, we'd be recoating after five to ten years, and could sand it down. These people were always cheaping out on materials and doing things that were more work and expense in the long run. One of the reasons I don't work for them anymore.

 

[Seahorse24]

One of the passenger boats I ran, the owners insisted on painting with acrylic. It was cheap, easy, and looked good for a couple years, bit we were recoating every couple years to keep it looking good. And being a dinner boat it had to look good. And forget about sanding it off . It just clogs the paper. If they'd used a proper oil enamel, even a cheap one like Rustoleum, we'd be recoating after five to ten years, and could sand it down. These people were always cheaping out on materials and doing things that were more work and expense in the long run. One of the reasons I don't work for them anymore.

Thank you for sharing your experience on a commercial boat painted with acrylic paint, Capt jgw. It was not a matter of money for us. We could have purchased an oiled based enamel for half of what we paid for the acrylic paint, but we want to experiment and let other boaters know how acrylic paint performs on a sailboat in a freshwater lake environment. We plan to photograph and document the status of our boat bottom and hull for others who may be interested.

If we have bad results, other boaters can learn from our mistakes. If it goes well, others may decide to follow suit and start using 100 percent acrylic paint. My son and I have owned several boats and watercraft since 2001, nine total. We have used Rustoleum and other oil based enamels on water craft and flat bottom boats. We know the results of those products so we decided to try something new.

Based on my testing, the acrylic is actually more difficult to scratch than the oil based enamel. You are right about sanding. Oil based paint is much easier to remove with sanding than acrylic paint. Once the acrylic paint is completely dry, it is no longer water soluble and is fairly difficult to scratch. My son had doubts until he had to use a screwdriver blade edge to finally scratch completely down to the epoxy layer. I did my testing with the edges of rocks, but our sailboat will not be beached like we do our fishing boats and other power boats, so hopefully we won't hit any rocks or screwdriver blades after we get the boat in the water. The bottom will encounter two twelve foot long bunks each time we lift the boat out of the water. That is where I expect to see some wear and tear on the bottom paint.

We have air-powered sanders and a large belt sander that can take any kind of paint off the bottom, including epoxy. We applied three new two-part epoxy barrier coats to the bottom prior to applying the acrylic paint, so if any of the acrylic paint was to come off, the bottom will still be water tight.

What I like about the water based acrylic is the ease of touch up or repaint, so I hope our experiment goes well.

 

[njlarry]

Very interesting. What brand of paint did you use? Blog address?
Thanks for sharing your experience.

 

[Seahorse24]

Very interesting. What brand of paint did you use? Blog address?
Thanks for sharing your experience.

Thank you for your interest in our project, Njlarry.

We are using Valspar paint, because it uses nano technology and is 100 percent acrylic paint. Photos of the paint cans are shown on the blog.

I will be updating the blog with photos of the bottom paint progress soon. We have dozens of photos that have not been posted yet. Here is the blog address.


https://sailboatprojectorbust.wordpress.com

All lights will be changed to LEDs. After we finish restoring the outside, we will begin restoration of the interior. New cushions, wood refinishing, etc.