Painting over gelcoat?

I’ve recently traded my well used Browning Alumaboom of 30+ fun years for a vintage 1984 Wenonah Jensen 18’. I’m not sure about the date, but it’s what the previous owner told me. It’s in relatively nice shape for its age, solid with good gunnels, but the bottom is really scratched up, beyond what I believe can be sanded out. I’ve painted quite a few cars and still have the equipment so I’m trying to find out if there is any reason why I can’t paint this canoe. My questions are 1)What materials are best for surface prep over gelcoat?; 2) What is best paint to use that is durable? – the tougher the better.

The canoe is green and weighs 55lbs so is it safe to assume that it’s some sort of fiberglass composite rather than Kevlar?

I have more questions, but they can wait for now. Any help will be appreciated.


Painting over gel coat

– Last Updated: Sep-16-12 8:33 PM EST –

The Jensen 18' is a great boat. I've always wanted one.

If the sides of the boat are not too bad you might consider wet sanding the sides (if necessary), applying a polishing compound and buffing the gel coat, and just painting the bottom. That would save weight and the bottom could be touched up and repainted as needed. If you want to do that, put the boat on a level surface and mark a 4" waterline using a stick, or something 4 inches in length.

I have just washed gel coat and rinsed well, and wiped it off with denatured or isopropyl alcohol before painting and that has worked fine.

Obviously, spray paints are the simplest to apply and have the advantage of being easy to touch up if you get scratches. Some folks think Krylon Fusion paints are a little more durable, others don't.

If you are looking for maximum durability I would probably go with a 2 part marine polyurethane like Interlux Perfection.

The boat might possibly be Kevlar composite. Does it have a core? Wenonah listed the Tuf-weave (fiberglass/polyester proprietary composite) with standard equipment at 56 lbs, but standard equipment would be aluminum trim and Wenonah's aluminum gunwales were/are very light. The wood trim usually added a couple of pounds.

The Kevlar hull with cross ribs or center-rib stiffening was listed at 53 lbs. If your boat is one of these the cross ribs or center rib should be readily apparent.

Painting over gelcoat?
Thanks for the reply. I’ll look into the Interlux paint. Sounds like what I’m looking for.

As for the core, I’m not sure what you mean. What it has are five ribs about 3" wide. One is just in front of the stern seat and the other four are equally spaced to just aft of the bow seat. The floor has a thick composite material, possibly foam core, that covers the lower parts of the ribs. The canoe shell has no core that I can tell. Very thin and I can see light through it.

Another question. What is the mood of installing Kevlar skid plates? On my canoe the keel gelcoat as been warn off to expose the glass fibers.


Sounds like Tuf-weave PVC core boat

– Last Updated: Sep-16-12 9:26 PM EST –

The thicker portion of the floor is in the shape of an elongated diamond, right? That is the PVC core. You can't see the PVC material because it is covered with cloth on both sides. A core is a way of stiffening the bottom of the hull without adding much weight. The Wenonah PVC core boats had PVC ribs extending out from the core up the sides of the boat. Between the ribs, the layup is very light.

Wenonah listed the Kevlar hull with PVC core at 38 lbs and the Tuf-weave hull with PVC core at 56 lbs. Although not as light as the Kevlar hull, the Wenonah Tuf-weave boats are very sturdy.

Don't use Kevlar felt skid plates. Kevlar felt is not very strong at all and it chips off fairly easily. It is also quite thick which adds drag.

You might just cover the exposed fibers with some epoxy if the gouges are not too deep and you are going to paint over it anyway. If you have deeper gouges you can fair them in using epoxy thickened with something like colloidal silica powder. If you have deep scratches on the bottom you could also fair them in with thickened epoxy and then wet sand before painting.

If you apply an abrasion plate use either Dynel cloth or 2-3 layers of fiberglass cloth (S 'glass is better than the "standard" E 'glass). They won't be any harder to apply than Kevlar felt plates, they will be stronger yet thinner, and look better.

Jamestown sale
Jamestown has Interlux boat paint on sale with free shipping, including Brightsides, Prekote, 2 part, etc. Seems everyone has a different opinion about which is best for the hull.

Painting a composite boat
I’ve posted these many times for similar questions as yours.

I had picked up a Sawyer Summersong that was in reasonable good shape but looked like crap…

Once I stripped the paint off, I found it was red and the gel coat was in poor shape and some patches on it were poorly done.

I sanded it down and applied a prime coat and then spray painted it with a fairly expensive automotive paint.

Here is the final result…

In hindsite, I should have used inexpensive paint. The canoe has a bunch of scratches now and if and when I decide to touch things up a bit, I’ll go to home depot and get something cheap.

Painting over gelcoat?
Thanks for the response, I appreciate it.

The sides aren’t bad, but slightly marked up. That’s a good suggestion not painting the sides to save weight and I’m still considering that, but I don’t have paint yet so I’m not really ready to make that decision. That side gelcoat is very thin and can’t take much sanding.

I’ve pretty much homed in on the 2part Interlux as it should be about as tough as I can get, other than respraying with gelcoat which would be too heavy.

Still don’t know if Kevlar or not, but doesn’t really seem to matter much. It is what it is and the weight isn’t much different. The wood gunwales are in good shape, but haven’t seen any care in a long time. A nice sanding and urethane coat should make them look great and give good protection.

Again, thanks for your input.


Painting over gelcoat?
Hey, thanks for the tip! I just talked to the reps at Jamestown who were a big help, but also told me the no-shipping charge sale ends tonight at midnight. Gotta make a decision. I plan to spray so I’ll probably need thinner.


Painting over gelcoat?
Hey, Andy. Thanks for the great photo spread. You have a ton of work into your canoe, but something you can be proud of. Good job!

gelcoat paint
I have painted lots of canoes after repairing them with good success. I would be leary of a fiberglass boat as old as 1984. I had a Sawyer Charger made of kevlar that finally caved on me. Hope that the boat has not been in UV light much (used or stored outside).

A lot of times you can recognize kevlar by the coarseness of the cloth. The early boats were often gold in color.

I have painted fiberglass canoes with everything from porch paint, aerosol cans, etc. but epoxy paint made for boats or high quality enamel. It will still get scratched but can easily be touched up and will cheer you up. I wouldn’t over thing it. Many types of paint will work and be a huge improvement over what you have.

Consider painting a waterline on your boat and painting just the bottom. It makes it easy to trim the boat when paddling.

gelcoat paint
No, as far as I was able to determine, when it wasn’t being used the boat spent most of it’s life hanging from the rafters in the pole barn.

I’ve pretty much settled on Interlux 2part urethane.

No hurry applying it though. It’s still water tight and it will be a good winter project.


bottom patch
I’ll be glad to share the bottom patch paint protocol; email

Interlux 2 part urethane …

– Last Updated: Sep-19-12 11:17 PM EST –

...... since you said your intention is to spray it on , be very careful about how you go about ... read the precautionary info. from Interlux regarding respiratory protection when spraying a 2 part urethane .

On the other hand , roll on and tip off is a safe method of application ... the product has excellent leveling properties .

Also you said you have the spray equiptment and spray experience on previous autos ... that being the case I suggest you prep the hull properly with washing , sterilizing (acetone wipe as needed) , fill the sceatches/gouges and fair it , 3M Vinylester is a good product for the filling , sand till fair and smooth , and then spray new gelcoat (mechanical bond) . Gelcoat is tough ... paint (even 2 part urethanes -read expensive) are not tough and scratch right up . Canoes get much , much more use abrassion than power and sail boats do .

Read up on how to spray apply new gelcoat over existing gelcoat (pressure , tip size and thinning). Even a so so gelcoat job that you don't take to mirror finish is still way better than any paint job when it comes to wear and tear durability . As you build the mill thickness of the gelcoat , remember the final coat has to be waxed in order to surface cure ... prior build coating is non waxed and you have but so much time between coats to achieve a good chemical bond between them ...

For what is worth , slow cure epoxy like West System 206 catylist and 105 resin is tough as nails against abrassion . It can be color tinted to a degfree and rolled on after a good fill and fair job . It's a good idea to thin it about 10% to help kept the out gassing bubbles to minimum . The thing with expoxy is it is not very UV resistant but the good news is it touches up easily .

Special Chemical May be Needed

– Last Updated: Sep-19-12 11:49 PM EST –

The first thing is to make sure that all mold release, waxes, and any 303 or other protectant is removed. Use Interlux 202 Fiberglass wash if allowed by your choice of paints...

Then it all depends on what kind of paint you want to use--Awlgrip, polyester, epoxy. Some need controlled curing conditions, others dont. Use a marine paint and follow the instructions from the manufacturer.

Stick with a system from one manufacturer-- eg Petit or Interlux. Paint made bymanufacturers who do not make primers and solvent washes will generally recommend a brand to use that has been tested for chemical compatibility.

Interlux 2 part urethane …
Thanks for taking the time to respond and the great advice. The tip about using good quality resin as a bottom coating was a good one, not to mention applying gelcoat. Unfortunately, I took advantage of the last minute sale last night at Jamestown and purchased the 2part epoxy paint+reducer. My plan is to keep the paint as thin as necessary to cover. I don’t know if my plan is a good one or not and I might decide to roll/brush it on rather than paint when that time comes. Then again, I like the idea about spraying on gel coat, but the weight concerns me.

Not worth it to me
I have never personally painted a hull, so you should probably stop reading this post now.

However, I did have one of my Royalex hulls restored by a professional who said he was using one of the highest quality marine hull paints. Don’t really recall what it was.

Result? The stuff added a LOT of weight and scraped right off the bottom after a few runs down some 80 fpm New England streams. The bottom looks much worse than ever with the old red vinyl showing through the white paint.

My conclusions for me? First, I just accept the scrapes and scratches and don’t worry about them any more. Second, if I did refinish, I would only consider doing so below the waterline. However, you don’t see that part of the boat when it’s in the water or on top of your Hummer. Finally, if something compelled me to refinish below the waterline, I’d do so using the cheapest stuff possible

Not worth it to me
Thank you for the input. It all helps. As for Royalex, isn’t that more of an ABS type of plastic, or at least the outer layer? If so, I’m not sure there is ANY type of paint that will stick to it, regardless of how much you spend. If I’m correct in my thinking, pretty much any small scrape along the bottom would show up, especially with a contrasting under layer.

I guess my thought process is that it is a very expensive and quality canoe that I got for a very good price and $100 is, to me, a reasonable price to pay for a good repair. I agree that painting below the water line is a reasonable plan and will save weight and paint. I ordered a 2part quart of Interlux and I doubt very much that I will use maybe a third of it so additional weight should be minimal. In the end I may be eating some crow over this, but here in NE Michigan the winters are long and boredom can be chronic, so projects out in the shop are often welcome.

One question. Using my Wenonah Jensen 18, without putting it in the water, is there a rule of thumb and method to determining the water line?



ABS. Waterline.
Yes, my boat was Royalex, but the outer layer of a Royalex layup is vinyl plastic not ABS. The ABS is under the vinyl. But maybe nothing sticks well to vinyl either.

Refinishing is also a function of a certain psychological frame of mind. I had just wrapped a relatively unscathed Whitesell Piranha around a bridge abutment below Satan’s Staircase in New Hampshire and I was mentally traumatized by the damaged appearance. So I had it all repainted while it was being re-railed. I am no longer of that frame of mind (and I no longer run unscouted whitewater in New Hampshire).

I am also not interested or skilled in fixing things. But if you are and already have the paint, why not try the waterline approach first and see how it looks and functions. I assume you can always paint the whole thing later if you want.

I’ve been cogitating about the waterline question and really can’t think of an accurate way to do it without floating the boat, which is easy enough to do. On the other hand, I’m not sure perfect exactitude really matters unless you plan on using the paint patch as your only hull trim guide. After all, when you are in the boat you can’t see the paint patch and you can measure trim by other means.

So, I am preparing to paint an 84 Wenonah Sundowner 18 right now, and the repair guy from our regional boat shop suggested the same waterline approach. In my case, though, the boat is pretty banged up both above and below the waterline. I’ve made some glass and expoxy repair to the bottom, and a couple of dings on the sides, which need protection. I want to make an aesthetic improvement in addition to prolonging the life of the boat. Do I paint the bottom with a heavier duty marine paint, and then the sides with something lighter? Or just do the whole thing with marine paint if I’m going to bother painting the whole thing? The layup is kevlar and very light, and we are very mellow recreational canoeists, so I’m not concerned about a little extra weight.