A two-part urethane clear coat will be clearer, harder, and last much longer than varnish, but is expensive and can be difficult for an amateur to use. If you try it, be sure to use a good respirator.

I have found that single-part Minwax Helmsman Marine Urethane is easy to apply, exceptionally clear, and lasts a lot longer than varnish.

-Wes

I know a guy that did it because his brother-in-law was a car painter.  It came out looking very nice, smooth and shiny.  Its truly clear, no hint of amber that varnish gives.  It is prone to swirl marks but a quick and simple buffing/polish a couple times a year keeps it looking great just like a car.

I'm no expert by any stretch, but are you folks talking about clear coat or Minwax varnish over epoxy?  How do you know it's providing the UV protection needed?

Personally I would stick with a company like Interlux that specializes in marine paints and varnishes.  If you look at Minwax's website they say the varnish is for furniture and that kind of thing--no mention is made of marine use, even though it says Marine on the label. 

Unless you are absolutely sure you get the UV protection you need for the epoxy I would stay away from anything that is not intended for marine use, e.g. Interlux Schooner Gold.  I'd much rather have a yellowish tint than "crazed" epoxy that has to be sanded down to the wood and replaced, but that's just me. :-)

Hey Duck,

You're right, there's no reason to have UV inhibitors in clearcoat, you hardly ever see cars out inthe sun :-)

Laszlo

Minwax Helmsman Marine Urethane is clearly labeled for marine use and UV protection. The Minwax finish on my Merganser still looks like new after three years of sun exposure and hard use in both salt and fresh water.

-Wes

Well OK, I stand corrected.  I'm still sticking with Interlux, though, mostly because I don't know that much about it and will stick with what is recommended.

Interlux Compass Clear...

http://www.yachtpaint.com/usa/diy/products/varnishes/compass-clear.aspx

I will varnish my car this weekend to test it.

Kim

There is a startling difference in clarity and brightness between urethane and traditional varnish. I have had several experienced kayak builders comment on the beauty of my boat without realizing it's the finish that makes it stand out. -Wes

Wes,

How does it hold up to abrasion?

Dan

Dan,

I don't often scrape the top of my boat, and the hull is painted, but there are no scratches on the deck after three years of hard use. Even the area behind the cockpit, where I brace the paddle when getting in and out of the boat is not badly scratched. The hull needs to be painted again, though. There is one white paint spot on the deck where I whacked it against the garage door trim. Once it's cured, the urethane seems to be much harder than traditional varnish.

Wes