Hi All,
I wanted to build on a question raised in another thread to ask for experience builders have recently with ‘clear’ (not amber colored) marine suitable varnishes.
about four years ago i used a two part clear coat, Bristol Finish UV Clear two part (now sold by MAS) with great results…but the two part was kind of a hassle and the price is up now to $76 a quart. and most of the kayaks i am building need a quart at least for a really good finish…(four to six coats with light sanding between coats).
as i explore, i see several one parts that claim to be clear that appear to be focused on marine use and i am curious if anybody has direct experience with any of these and can share 1) is it truly clear? (i.e., like fresh water - no tint or color); 2) how was it with respect to ease of application?; and 3) any comments on how it is holding up. Also, if there is a brand or clear coat with good UV protection suitable for marine use and able to be applied by brush, that isn’t mentioned, please share… the three varnishes i found and approximate pricing are below.
-
interlux Compass Clear $40 a quart
-
epiphanes clear gloss with Extra UV filter $32 a quart
-
rustoleum marine coatings spar varnish clear $20 a quart
thanks everybody 
So here is a more fundamental question. Can a marine varnish be water based? Total Boat makes Halcyon which is water based but not very satisfying to use. It does not self-level very well and, despite being clear, the result is cloudy (IMHO). I am currently varnishing the mast of my sailboat using General Finishes Exterior 450 varnish. It is super clear after 4 coats. It goes on beautifully with a foam brush. The material data sheet says that it is not intended for horizontal exterior surfaces like table tops but kayaks are not generally stored immersed. It is on the thin side so it takes quite a few coats to achieve a reasonable firm. I intend to use 6 coats on the mast I am varnishing.
As far as I can tell the primary reason why we varnish our wood kayaks is to protect the epoxy from UV damage. All exterior varnishes, including water based ones, contain UV filters. The question I guess is how they will hold being immersed repeatedly. Is this situation any different from oil-based topside finishes being used on hulls of small sailboats and kayaks that are generally stored out of the water.
Hey Howard, I have not used any of the clear varnishes on your list, but I have used Epifanes Rapidclear on two race kayaks and the Goat Island Skiff. It is a very easy to apply semi-gloss that can be over-coated after 5 hours without sanding. Obviously it does not result in a furniture grade finish like a high gloss but it is more scratch resistant and has held up well.
Here is first coat going on the Yukon. As you can see, it is quick clear, no tint.
This picture shows all four race boats for comparison. The bottom and top boats (Yukon and decked Spindrift) were coated with Rapidclear. The third boat up (Mystery) has a couple coats of the tinted Rapidcoat then Rapidclear. You can see that it is a little darker. The second boat up is the Wahoo and it has Interlux Schooner. Hope this helps.
I keep my sailboat rigged on a mooring for 5 months a year in a salt water environment. I figure this will be a pretty good test of using a water-based exterior varnish instead of a traditional oil-base spar varnish. Will post before and after images next fall. Mast is Sitka so failures will be easy to spot.
