I know… I’ve been promising to write an update on the Canoe and Kayak Coating Abrasion Test that I ran back in the Winter/Spring of 2008. In the past month or so there has been a lot of discussion about it on Björn Thomasson’s website. Here it is… finally. This update mostly concerns the “white graphite.” Actually there’s not much more than what I wrote in a comment…
At this point we can not recommend using the white graphite (at least our version). We used the “Azure” Njord as a long term testbed for the white graphite. After a year of use in both salt and fresh water we came to the conclusion that although it worked great in regards to abrasion, it actually stained (fouled) quite easily. It was very difficult to keep white. Notice the staining in the images below.
The hull needed to be recoated. One option was to modify the white graphite (perhaps adding some dry Teflon would help?). Another thought was to add the white graphite powder into a topside urethane paint (something I may look into). In the end the hull was recoated with a hard epoxy-based bottom paint made by Interlux called “VC Performance Epoxy.” It’s designed for trailered sail and power boats and can be burnished. It sprays beautifully through my HVLP gun and has no nasty isocyantes like the urethanes. We did not make test samples of the bottom paint for the drag sled. We should have. It would have been interesting. It is now the standard for white-colored hulls.
The black graphite mixture using West 423 powder is proven and whole-heartily endorsed. The hull of the one commercial kayak I made last year (a real hybrid: strip hull and SOF deck) was coated with black graphite. From what I have heard it has held up very well.
In summary: All of our white-colored hulls will now be coated with either VC Performance Epoxy or a urethane. For now, I will not support or endorse the use of my version of the white graphite. Black-colored hulls can be coated in either graphite (preferred) or a urethane. All other surfaces (decks, accessories, etc) will be coated in a colored or clear urethane. Until we have a spray-booth Interlux Perfection urethane applied by rolling and tipping will be standard. As an option any urethane surface can be professionally sprayed with an automotive-style hi-performance urethane, for a slight increase in cost. Also, for those that prefer a traditional look and feel, I will gladly substitute the urethane with a one-pot marine varnish for any boats finished bright.