I picked up an old kevlar tandem race canoe, a Crozier to be exact.
The exterior of the hull is slightly faded and I am wondering if there is something I can put on it to restore the gloss and protect it from further UV damage?
I am in the process of re-varnishing the gunnels and where I got a little on the hull I noticed that the varnish does a pretty good job of bringing the bright yellow color back. Would that work on the entire exterior of the hull? Sorta thinking it would crack and flake off over time.
What about paint? I’m not against painting it, since I was never a big fan of the yellow Kevlar look. Is there a good marine paint that would withstand the flexing of the kevlar hull?
I picked up an old kevlar tandem race canoe, a Crozier to be exact.
I’ll probably get shot for this
suggestion but I’ve used polyester resin on my Kevlar hull to do light repairs and hide scratches. It dries quickly and you have to use it outside because of the fumes.
Why will you get shot ?
I do the whole canoe with it.
I have done several, and they look new and are good for another seven or eight years.
don’t have the right answer
But I can tell you that varnish is the wrong answer (IMO) as it will do exactly what you fear - yellow and crack over time. It could look really good, but will commit you to regular cycles of pretty high effort maintenance in the future.
Poly is probably fine as long as it is a poly resin boat (if it was manufactured on a line, it probably is) as opposed to epoxy.
I think I like that
I was not familiar with that. Did a quick search for polyester resin and says its great for a final coat. Sounds perfect. I am assuming it is somewhat different than regular resin used for glassing, like system 3 or west system.
Any recommendations on brand, looks like a bunch of choices?
What do you guys do for surface prep?
try wet sanding and buffing
If you don’t mind investing a little time, I would try wet sanding the hull which I assume to be gel-coated.
If nothing else, this will be a good surface prep for anything else you do next so it won’t burn any bridges. Often, wet sanding will do quite a bit for restoring faded gel coat.
I use waterproof paper starting with 180 grit and working in stages down to 1500 or 2000 grit. You might have to go to an auto store for some of these very fine grits. So the sequence would be something like 180-220-400-600-800-1500 say.
If after your final sanding the hull looks like something you can live with, especially when wet, I would then apply a good polishing compound like those made by 3 M and buff the hull with an electric automotive buffer, if you can find one.
If your hull is gel coated the gel coat is almost certainly a polyester material so polyester resin will bond to it. Polyester resin and polyester gel coat will not bond reliably to epoxy and some other resins, however.
I have used both resin (in my case epoxy) and varnish on hulls and they do restore gloss. In my case, I used varnish to cover epoxy resin to provide UV protection. I have not noticed any tendency for the varnish to either darken disagreeably or flake of as yet, but the hulls I have done this with have been dark so perhaps the results would have been different with a lighter gel coat color.
If you have a lot of scratches in the gel coat on the hull bottom but the sides are pretty good, you might consider just painting the bottom up to a 3 to 4 inch water line. If you use something easily applied, like spray paint, it is quite easy to mask off the hull and spray a new coat on the bottom as it gets abraded. Just painting the bottom saves weight over painting the whole hull.
To mark a water line find a level place with a regular surface, like a deck or patio, to place the boat. You might need to use a stick on either side clamped to the gunwale, to prop the boat upright if it wants to heel to one side or the other. Use a carpenter’s level to make sure it is right. Make a little rectangular block of wood 3 to 4 inches tall (where ever you want your waterline) and tape a Sharpie to the top horizontally. You can then go all the way around your boat and mark a consistent water line.
Probably Epoxy skin coat
It’s a crozier, so probably skin coated with Epoxy resin. One could call and find out, but sanding and buffing might be contra indicated.
If it is epoxy skin coat, best not apply polyester resin to it.
I have used System 3 Clear Coat epoxy on weathered hulls. It is a very low viscosity resin. But if it was not protected with a coat of UV protecting varnish or polyurethane, I don't know how badly it would degrade over time or whether it might blush.
Covered with a coat or two of marine varnish, it looks fine.
I wish I was at home, but I am not
and am not sure of the West systems numbers I use.
Call up West systems, and they will walk you through the whole process as well as send you the literature
Get their pumps which will dispense the proper mixture.
On prep, all you have to do is sand everything lightly, and then wipe with acetone.
You should be quite happy with the results and if it is done right, you will have a new looking boat.
Don’t store it in the sunlight, since direct sun is it’s worst enemy - No problem car topping to and from the water.
Don’t confuse polyester with epoxy
If Charlie Wilson is correct and your boat is skin-coated with epoxy the last thing you want to do is apply polyester resin to it. It very likely won’t cure and you will wind up having to scrape it off.
Furthermore, West Systems makes epoxies, not polyester resins. I have used System 3 Clear Coat epoxy to rejuvenate the surface of canoes. It is very low viscosity and does well to fill in small surface imperfections, scratches, and to some extent even checkering and spider cracks in the surface.
If you choose to use a West System product, you probably want to use the 105 resin with the 207 special clear hardener.
Think more I think about it
My cedar strippers are epoxy and are finish coated with varnish for UV protection. One is 11 years old the other is 12 and they both look great yet. The one had quite a few bottom scratches so I lightly sanded and put another coat of varnish on a few years ago, holding up great.
If the outside of this hull is the same material as the outside of my cedar strip boats why wouldn’t varnish work?
I guess I need to try an contact the builder and see what he thinks.
Anyone have any contact info for Crozier? Is he still in bussiness? I found an old email that didn’t work and a phone number that also didn’t work.
It will work
The outside of a strip built boat is resin impregnated cloth, just like the outside of a non-gel-coated canoe is. Sure, eventually the varnish may weather and get too scratched up, and when it does you give it a light sanding and put on some more.
But if your boat is skin-coated and there seems to be areas where the cloth is getting exposed or appears resin-starved, there might be some advantage to applying a coat of epoxy first.