Finishing Pinguino With WR-LPU


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Water Reducible Linear Polyurethane (WR-LPU); I love this stuff!  After much debating about whether to use WR-LPU or stick with the supposedly less risky Spar Varnish, I settled on WR-LPU.  WR-LPU would give me a glossy finish, but not the high gloss I’d get with varnish.  I didn’t want a high gloss finish because I felt it would show every scratch and imperfection in my finish work.  Also, WR-LPU, a two-part finish from West System, is reported to be a much harder finish than varnish, more resistant to scratching to begin with.  Finally, it is less toxic than spar varnish and cleans up with water!

That being said, the warnings about the difficulty of getting a good finish, and the recommendation to use spar varnish gave me pause.  It was said that the product would dry too quickly.  That there would be marks where the wet and dry product overlap. That heat and humidity were critical.  Well, either I can’t tell a good job from a lousy one, or difficult work from easy, but in the end, I found nothing difficult about using WR-LPU and I got a great finish in record time.

Here’s what I did. 

  • First, the temperature on the two days I applied the product fell between seventy-five and eighty-five degrees.  The humidity range was sixty to seventy-five percent, really perfect for the application of WR-LPU. 
  • Second, I reduced the product with water by twenty percent and added the hardener to the water before adding both to the WR-LPU (as recommended). 
  • Third, I mixed up half of my quart of product for the hull.  I found that the product in bulk does not set up for hours.  I had more than enough after applying four coats to the hull to do five coats on the hatch covers and two coats to the inside of the cockpit.  Two days later I mixed up a quarter of the quart (half of the remainder) in the same way and had enough to put five coats on the deck. 
  • Fourth, and this is critical, I had help.  My friend Sandy applied the WR-LPU to the boat in small sections with a roller and I followed up tip brushing the application to remove bubbles, etc.  While I did this, Sandy rolled another section, and so on.  This way, no section ever had a chance to dry out before we got the next section painted.  It would take us about fifteen minutes or so to complete one coat.  Then we’d go have coffee for thirty minutes and come back for the next coat.  We completed four coats on the hull in about two hours and five coats on the deck in less than two and a half.  It would have taken days to apply spar varnish.  And then I would have had a piece of furniture, not a boat!

I don’t know if others have had it this easy applying WR-LPU but, based on my experience, I would highly recommend this finish. 

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© Don Yackel 2016