Features September 2011 Issue

Exterior Wood Finish Test Two-year Update

Two-part varnishes leading in durability as long-term test reaches 24-month mark.

Like spotting land after a long passage, we’re glad to say that the end of our longterm exterior wood finishes test is finally on the horizon. Time, weather, and Southwest Florida’s unrelenting sunshine have clearly taken their toll on the test panels over the last 24 months, and as the evaluation moves into its third year, only 19 of the original 54 test products will continue on in our survival-of-the fittest finish matchup. Given that most wood coatings are rarely expected to last longer than two years in the marine environment—particularly in super-sunny locales—it’s no surprise that we’ve seen more significant changes in the coatings in the last six months than we had in previous checkups.

Varnishes
Bottom photos by Frank Lanier

After two years of testing, its apparent that two-part varnishes are the most durable type of exterior wood finish.

Our search for the ideal wood finish—relatively easy to apply, easy to maintain, lasts multiple seasons, and is affordable—began in 2007 when we took a look at the different types of exterior wood finishes on the market, their pros and cons, and how easy they were to apply (one-part varnishes, August 2007; varnish alternatives, October 2007; two-part varnishes, December 2007; teak oils and stains, April 2008). Launched in 2008, the longterm panel test aimed to determine which type of coating offers the best and longest protection and which products stand out among their peers.

We hope the comparison enables readers to decide which finish best matches their own taste, potential labor investment, and wood protection needs. For more on the differences between wood finish types, check out “Wood Finishes 101,” which appears with the online version of this article.

We’ve rated the test products every six months and reported on the coatings’ durability in the May 2009 (six-month checkup), December 2009 (12 months), and January 2011 (18 months) issues. Here, we offer the two-year report on the survivors.

How We’re Testing

Testers applied dozens of exterior wood finishes (22 one-part varnishes, six two-part varnishes, 18 synthetics and satins/varnish alternatives, and eight teak oils and sealers) to small panels of bare solid teak. Each was assigned a number for blind judging and was applied per manufacturer’s instructions. If makers gave a range for the number of coats to apply, testers went with the minimum.

Initial testing rated each product’s ease of application and original gloss and reflective qualities. In the summer of 2008, the test panels were mounted on a wooden rack (aka: “The Rack”), which was set up in an unobstructed area on the roof of the PS workshop in Sarasota, Fla., to ensure that all panels received the same amount of weather exposure. The top part of each panel was covered to create a control area that testers used for comparison over time. Every six months, we disassembled The Rack and rated the panels on how well their coating integrity, gloss, and color had fared over time with constant exposure to the elements.

The test was designed as an endurance test, a fight to the finish, so we have not done any maintenance coats or touchups to the test panels. These products can be expected to have much longer lifespans if they are regularly maintained. (Find tips on keeping your brightwork healthy with the online version of the report.)

How We’re Rating

Testers rate each panel on three longterm performance criteria: coating integrity, gloss retention, and color retention. Excellent and Good coating integrity ratings mean that no maintenance is needed; a Fair indicates that it’s time for a maintenance coat; Poor means the fat lady has sung, and the coating would need to be removed and re-applied. Excellent ratings are given only to those with an uncompromised coating. This time, panels with Poor and Fair- coating integrity were pulled from the test.

Color and gloss retention ratings are relative to the panel’s original finish. Initial gloss and ease of application are relative to the field within each coating category; these were assigned immediately after the panels were coated.

It was tougher to pick Recommended coatings at the two-year mark, as most wood finishes aren’t intended to go that long without maintenance. One-part varnishes that earned PS’s recommendation this go-round were rated Fair for coating integrity (none rated better than Fair ) and had no Poor ratings. Recommended two-part systems rated Good or better for coating integrity with no Poor ratings. No varnish alternatives or teak oils/sealers were recommended at two years.

What We Found

What a difference a season makes! With the exception of a few two-part products, the test coatings had lost their sparkle at the two-year mark. Ratings slipped across the board. The UV abuse had obviously taken its toll, sucking the life out of most of the coatings, particularly the clear finishes.

Those clinging to life with Fair coating integrity are still protecting the wood, but they’ve lost their looks. In the real world, all of the one-part varnish and varnish alternative test panels would be due for a maintenance coat, and some—like HMG K Type Varnish, West Marine WoodPro Plus (rebranded Epifanes Rapidclear), and Ace Spar Varnish—would be overdue.

The biggest overall decline was within the one-part varnish test group: Not a single one rated better than Fair for coating integrity or gloss retention, and nearly half of the test field was retired after this rating round. Just six months before, eight of the 19 products rated Good for coating integrity and six rated Good for gloss retention. In 12 months, seven dropped from an Excellent coating integrity to a Fair.

The one-part varnishes offering the most protection after two years are Detco Crystal, Le Tonkinois Vernis, and Pettit’s Z-Spar Captain’s 2067. However, their extended protection comes with tradeoffs: Detco rated only Fair for application, Le Tonk’s gloss started to slip after one year, and Pettit’s 2067 started losing its original color after 12 months.

One hardware store varnish has surprisingly held its own over the long haul: Minwax Helmsman Spar Urethane. At half the cost of the Recommended one-part varnishes, Minwax slacked in the color retention department, but it has proven its multi-season durability.

Four of the nine varnish alternatives have been voted off The Rack after two years, and none performed well enough to earn our recommendation for two-year wood protection.

Interlux Perfection


Two of the top performers, Interlux Perfection and Cetol Marine Light (with gloss) managed to hold on to their original color well through two years of testing.

The Cetol products are still at the head of the pack, albeit a somewhat mangy-looking pack. The cloudy, opaque look of the Cetol Marine and Marine Light products may not appeal to everyone, but the fact they’ve maintained their color for more than a year is a good example that higher-solids finishes tend to offer better UV protection.

The Cetol Natural (with gloss) test panel fell from a Good coating integrity six months ago to being dropped from testing. Its performance mirrors what we’ve seen in the field: Give it a little loving once a year with a scrubby pad and a fresh coat, and it’ll last the long haul.

It’s taken two years, but the two-part varnishes are finally starting to show their age. Surprisingly, the first products to be dropped from this group are two that performed well in past PS tests: Bristol Finish and Honey Teak. This is likely because the life of a wood finish in Florida is always going to be shorter than in our past test locales in New England.

The other two-parts are still holding up well, with Interlux Perfection and Nautiking Nautithane offering uncompromised protection and better-than-expected gloss after 24 months. Perfection has been reformulated since the test began and is now sold as Perfection Plus.

The “temporarily discontinued” (since 2009) Smith’s Five Year Clear has also proven to be a top-notch finish, but it’s not available at this time.

While HMG Acrythane XSC didn’t earn our Recommendation this time, it was a top 18-month finish, it still looks good, and it costs less than the Nautithane.

Conclusions

After two years of testing, we’ve come to accept that perhaps there’s no Holy Grail of exterior wood finishes. It would appear, unfortunately, that we can’t have it all: easy to apply, easy to maintain, long-lasting protection, and a budget-friendly price tag. The reality is that, like much in life, wood protection is all about compromise and balancing your needs with your wants.

There’s no one-size-fits-all solution, and the boat owner who finds gratification in the wet, glossy look of a two-part varnish borne of painstaking preparation and careful application will weigh our test data much differently than the one who regards brightwork maintenance as a masochistic endeavor. For the latter, we recommend seeking out a varnish alternative (easy to apply, easy to maintain) that suits your tastes. With modest maintenance, the Cetol products with gloss overcoats have proven to be the most durable.

For areas where slippery-when-wet coatings won’t do, Cetol Natural (without gloss overcoat) or our top-pick teak oil, Star brite’s Tropical Teak Sealer (classic teak) should be considered. The Star brite will need to be reapplied every three or four months.

If you’re looking for a harder, more abrasion-resistant finish that’ll make it past the year mark, check out the top one-part varnishes like Detco Crystal or Pettit’s Z-Spar Captain’s 2067. Boat owners in sailing areas that see less sunshine than our Florida test site should also consider Pettit’s Flagship 2015 or Captain’s 1015. One-part varnishes require a little more work upfront and quick attention when they are scratched or dinged, but they also offer a more traditional, high-gloss look. The one-part varnishes in our test slipped dramatically after a year and half, so we suggest an annual maintenance coat, whether they look like they need it or not.

As this test has shown, when it comes to long-lasting protection and gloss, two-part varnishes just can’t be beat. They may be a pain to apply—and should you let the coating fail, you had better invest in a heat gun—but their durability is unmatched.

The top two-part after two years of testing was Interlux Perfection. Because we’ve not yet tested the reformulated Perfection, the top pick honors go to Nautiking’s Nautithane. While its price tag ($120 per quart kit) is a bit hard for most of us to swallow, Nautithane earned across-the-board Good ratings after two years.

Comments (11)

Don't believe it's available in the US yet, but Awlgrip is marketing a clear covering from New Zealand they call Awlwood MA. It's a one part product that has a special primer. It's easy to apply, can be applied as often as 3 times in a day without sanding and retains its shine for at least a year (they claim 3, but I can only vouch for 1; have lightly sanded and reapplied 2 coats each year ) with an original 6 coats.

Posted by: jackonanthem | March 22, 2017 8:10 PM    Report this comment

I was sorry that you failed to include SEMCO TEAK SEALER in your list. As a Fisher 30 owner of 30 years I have been through them all. When a fellow member of FOG (Fisher Owners Group) showed me Semco that was the beginning of a new life: stripped all the old finish off all the teak (and Fishers have a lot of teak) and applied two part teak cleaner to the wood. Convinced that we had spoiled the boat we persisted and soon had a beautiful natural teak finish on which we smeared two coats of SEMCO (Honeytone) right after the other. While it did not shine, it was beautiful. Since then we apply one coat in Sept and two coats in April/May and we are done. I will send pictures to anyone who wants proof. Cheap. Easy. No sanding just wash. I guess the two year plan would rule it out. Mistake!

Posted by: Kipper | March 13, 2017 2:17 PM    Report this comment

It't too bad and unexpected that Epifanes 2-part polyurethane clear was not included with the other 2-part finishes, particularly since that brand's 1-part finishes were included. Maybe I'm out of the loop in Seattle, but aside from Interlux, I've not even heard of most of the other brands included with the 2-part products.

I've had a remarkably positive experience with Epifanes 2-part clear polyurethane that makes me suspect that it would have bested even Interlux in your test, had it been included. As it turns out, I unexpectedly did a 10-year test of my own, since, due to a variety of reasons, my 24-foot carvel-planked mahogany gaff yawl has been mostly sitting in its slip unused, except for brief motor excursions and maintenance haul-outs, waiting for me to retire and have time to give it the attention it deserves.

The 28' Sitka spruce main mast was sanded to wood in 2006 by a local yard. They then sprayed it with multiple coats (I don't recall how many) of Epifanes 2-part polyurethane clear before re-stepping it back on the boat. The yard followed the Epifanes instructions exactly since they had never used this product before. The mast has remained in place ever since, unshaded and unprotected, and fully exposed to whatever weather Seattle has offered.

Sun exposure is Seattle is undoubtedly milder than in Sarasota, but we get quite a bit of sun in the spring and summer, and my experience with 1-part finishes (always either Interlux or Epifanes) on teak cap rails and companionways in Seattle has been very similar to what your test described for 1-part finishes. Maybe the Sitka spruce holds on to a finish better than teak does.

In any case, I was amazed to watch the the Epifanes 2-part on my mast -- with no maintenance whatsoever -- continue to look terrific year after year. It was not until 2014 when the first small streaks of separation from the spruce started to appear, and there was no peeling until early 2016. I never observed any loss of the Epifanes' nice shine. Now, of course, I'll need to sand it back to wood and start over, but 8 years to failure on brightwork is unheard of, from what I've read and experienced. I plan never to use any other varnish.

Posted by: rsf | March 13, 2017 11:41 AM    Report this comment

After 7 yrs in the crewed charter trade in the southern Caribbean. We had to keep our boat looking good. I got real tired of fighting with varnish at such a low latitude. Switched to cetol light and never went back! (After stripping and sanding until wood looked completely blond), I Initially applied 5 coats of lite one after another ( no sanding between) with luck could get all 5 on in one day (. Try that with varnish). Let thoroughly dry, sanded with 220, and applied 2 coats off gloss. Every year did light sanding and 2 coats of lite and one gloss. That was it for the year! If I wanted it to look super sharp, I gave it a coat of gloss in 6 months. When sailing north to Lat 36 I could get 2 yrs. Over many years of this I am very happy that it works. And looks good too! The other part that I like about cetol is that it is so easy to work with and very forgiving. If you get a spot or area ( like the very top horizontal surface of a rail) that goes bear over time, just sand until the dark is gone and it looks all blond. Coat it and and it blends right in!

Posted by: Cutter | March 12, 2017 8:36 PM    Report this comment

The tests were done using teak. Would other woods such as mahogany likely do better?

Posted by: Mason | March 12, 2017 2:04 PM    Report this comment

Different set of challenges here in the subzero north. I tried several one- and two-part coatings on a Douglas fir bowsprit and teak companionway drop boards which spend the year outdoors uncovered. Nothing lasted more than a season at best. I ended up wooding and applying the same Cetol Natural we use on our home's heritage reproduction windows and doors. A pass with the sanding pad, followed by a quick coat and we're good to go for another season. Caution: don't apply Cetol (or anything else) when you can still see your breath.

Posted by: jimduff | March 12, 2017 8:34 AM    Report this comment

The older I get, the more I love that grey-brown colour and non-slip surface of bare wood.

Posted by: taxwizz | March 12, 2017 8:18 AM    Report this comment

Is anyone familiar with Semco Oil? I originally read about it in PS but can't find the article.

Posted by: five on red | May 27, 2015 3:20 PM    Report this comment

To be fair, Epiphanes does not recommend RapidClear as a final finish. It is intended as a quick way to build up coats since it requires only 5 hours before recoating. After 5 coats, with suitable sanding between coats, the surface is smooth enough for two (8 recommended for sunny places such as Florida) coats of Extra UV Filter.
I used this approach on our Bristol 38.8, located near the eastern end of Lake Ontario, and I received complements on the quality of the brightwork 12 months later. Although I did not have an unexposed reference sample the finish was still shiny after 12 months.

Posted by: BOB F | August 21, 2013 1:58 PM    Report this comment

I agree with Virgin Islands testing, Have had sample of Awlgrip clear in Florida sun for 5 years and none of the other finishes came close in performance.

Posted by: cbgann | September 18, 2011 8:16 PM    Report this comment

I've done long term varnish testing in the Virgin Islands, and was just sailing this summer on a boat I put varnish on 22 years ago. It's disappointing that you did not test Awlgrip's coatings. I have had fantastic results with both their single and 2 part systems. In my limited testing, Awlspar performed better than your top rated single part coatings. Maybe next time?

Posted by: Peter G | August 31, 2011 3:45 PM    Report this comment

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