My dory is currently entirely protected by water-borne coatings. The exterior and interior is painted with System 3 WR-LPU and brightwork (gunnels, rower seat, interior woodwork) is protected with General Finishes Exterior 450.
I pursued water-borne coatings because I had to store used solvents and then pay to dispose of it at our community recycling center at their quarterly house hold hazardous materials disposal Saturday. If I missed a particular day I was storing the used solvents for six months or more.
The upside of using the water-borne coatings is no harsh hydrocarbon solvents to breath – the coatings can be applied by brush or roller without a respirator and quick dry time so fewer bugs and dust in the final film and shorter times to recoating. Brushes and rollers can be cleaned up with water.
The downside is learning how to apply the stuff.
The System 3 WR-LPU is much harder than alkyd marine enamels like Easypoxy, Epifanes monourathane, or Interlux Brightsides. It is not as hard as the solvent based Interlux Perfection.
One challenge with the WR-LPU is its fast dry time. For me it requires a team of two for application; one to roll and another to tip. It dries too fast to roll and then tip. This system likes low temps and high humidity, which is what I have. It may not work in the hot and dry intermountain west. Even with the conditions I have I could not get a level finish without a few brush marks, so I leveled the finish by sanding. I have a festool 5-inch sander with dust collection so leveling was not fun, but not overly difficult. I put on a coat per day – three coats, then sanded, then another three coats, then final sanding. The intermediate sanding was to 320 using festool brilliant, final sanding was Granat to 1500, then Platin 2000 and 4000. The finish is more than adequate. If you recoat the LPU within 24h there is no need to sand between coats. It took less than an hour to paint each day and about a half-day for sanding.
I didn’t like the colors available directly through System 3, but found that a small company called Nelson Hobby in Lyle, Washington sells the System 3 LPU in all range of colors for the RC airplane hobbyist. So I had them match the Brighside Seattle Gray interior and Toplac Bounty exterior when I was repainting my dory.
The key to using General Finishes 450 is using golden taklon brushes, rather than foam brushes. Small golden taklon brushes can be found at artist supply sources, and larger ones from Homestead Finishes.
Crosslinker is available for both the WR-LPU and GF 450, and I used them.
So far I am happy with the performance of both coatings.