For coating your kayak there are a number of products you can use, but only a few of them make sense putting on your beautiful kayak. This is an investment you should protect, right?
Well, basically you should get a good Polyurethane for floor or boat use. Prices vary in ratio 1:4. It may be one or two component, where you add a hardener. It’s not hard to do but you have to stir thoroughly. You want it to have a potlife of at least 20 minutes, preferrably more. Each layer should settle in a few hours and they should be possible to apply wet-on-wet. If you have to leave them overnight your kayak will take a week to coat.
For the last two or more years and about 10 kayaks, including student’s builds, I have used 2 component Polyurethane imported from Marcin Bober in Poland. It works really well, the price is decent and he ships within a few days. Potlife is 40 minutes, the ratios are not so critical and it is easy to apply wet on wet with a roller or spatula, whichever you prefer.
There is bad poisonous stuff and ok poisonous stuff, and others I haven’t tried, which are 3x the price and not good for your health. Some take a week to put on and you WILL need a mask and no other work can be done in your workshop until the fumes settle. That might take more than 12h. Not joking here!
Then there is the good stuff, which takes ages to get and is an unreliable service, to say the least. I have ordered three times from there and waited a total of 5 months… The earth pigment colors I ordered the first time never arrived. No excuse, no refund. BTW, you absolutely need a minimum of 1,5 orders, then pay for shipping and 25% VAT/MOMS in Sweden. In total, it doesn’t come cheap. However, the end result is achieved in 2 days and is durable. The caveat is that it goes yellowish with UV after a summer. For my earth toned kayaks, I kind of like it. It will not suit all tastes and colors though. Skinboats’ product might be the nicest to work with regarding fumes.
Then there is the other good stuff from Tikkuriila, which one unfortunately has to buy in big batches and has a potlife of – well, minutes! However, you have to be two people working really, really fast, you have about 3 minutes to wet the cloth through and you have to buy 13kg for your first try. Not ideal.
Results of bad, poisenous PU below after a few pool sessions. Not what you want on your brand new baby! And no, I haven’t oiled the stringer too much there 😉
And here is the result of a much better PU compound