A trend in recent years has been the gradual elimination of exterior teak on boats. This is understandable, given the amount of time and effort required to maintain teak in any but its unfinished state. But there is no denying that teak can be attractive and functional, and because new teak treatments last far longer than those of 10 years ago, there is no reason one can’t have good-looking teak on deck without expending days sanding and brushing.
Teak has many wonderful properties. Its rot-resistant, dimensionally stable and has excellent non-skid properties. Under good conditions, its virtually maintenance-free…if you don’t mind the fact that teak weathers to a silvery gray. Trouble is, conditions are seldom ideal. Acid rain, other air pollution and dust can change that silvery gray to a grungy, splotchy gray-black tone thats very hard to love.
You could keep your teak presentable by bleaching and scrubbing on a frequent basis, but this doesn’t do anything good for either the teak or your disposition. A more feasible approach is to isolate the teak from the environment with some sort of teak treatment. Which is what this report is all about.
What They Are
Teak treatments come in a wide variety of products: oils, varnishes, dressings, sealers, stains and paints. They all tend to make similar (if generally non-specific) claims: Protection, Deep Penetrating, Lasting Beauty, Prevents Weathering. In past years weve observed, sadly, that most of these products looked better on the label than on real teak.
More recently, though, weve encountered some products that do work as advertised.
The job of a teak treatment is simply to provide a physical barrier between the teak and the sun, rain, dust, soot and pollutants that make up a hostile environment. There are two basic requirements. First, the treatment must protect the teak for a reasonably long period of time (say, one year or longer), and second, it should keep the teak looking good. Its not particularly difficult to meet either one of the requirements; its a good deal more difficult to meet both.
One can think of a teak treatment as a sacrificial coating, working something like your boats zincs. The teak won't degrade until the treatment fails. While the factors that lead to teak failure are many, putting a teak treatment over the wood places the focus squarely on dealing with ultraviolet (UV) rays. The treatments, almost regardless of what types they may be, can usually handle the soot, acid, water and grease, better than they can deal with UV.
Paint does a fine job in meeting a teak treatments first requirement-that of protecting the wood. The opaque pigment in the paint not only keeps the UV from penetrating the film and attacking the wood, it also protects, to a great extent, the film itself, except for its topmost layer. The problem with painting teak is it completely hides the color and grain, thereby losing the aesthetic and functional advantages of the wood.
At the opposite end of the teak treatment spectrum are teak oils. These do a great job of meeting the second requirement but a poor job of meeting the first. A teak oil is usually a non-film-forming oil with some transparent (or semi-transparent) pigment mixed in to provide a more pleasant color. In our tests, such products typically require reapplication every month or so. Our October 1, 1990 report on teak treatments equated teak oil with snake oil; a harsh judgment perhaps, but one that is largely justified.
Between these extremes are a large number of products that include oils with UV-absorbers added; clear film-formers (well use varnishes as a generic term, though some paint chemists may quibble), and pigmented film-forming stains.
Film-formers have the advantage of being physically stronger than oils, provide a thicker layer that won't wash or rub off. A film-former consists of a relatively thin liquid that, upon curing, becomes a solid. Varnishes accomplish this in combination with oxygen in the air. Two-component products, such as epoxies and polyurethanes, create a solid film by means of polymerization. Once you have a solid film, however, your problems arent over. UV can penetrate clear coatings and damage the teak, and UV can destroy the film. If you put some opaque materials into the film, it reduces the problem, but then youre back to paint.
A UV absorber is another alternative.
UV absorbers can be used in oils, varnishes and stains.They are transparent additives, chemicals that intercept the energy in the suns rays that would otherwise damage the teak and/or the teak treatment and use it to force a chemical change in the UV absorber itself. Result? The UV is kept from doing other damage, but some of the absorber is consumed in the process. What this means is that a given amount of UV absorber can only provide protection for a limited amount of time before becoming used up. Why not add more absorber? The primary reason is cost-UV absorbers are expensive. A secondary reason, of course, is that you need enough of the other components to form a continuous film.
There are other problems. Stray UV that isn’t absorbed by the absorbers can break the long chains of molecules that make up the solid film. When this occurs, the broken chain ends can re-attach themselves to other chain ends, eventually replacing the long chains (which make for flexibility) with densely cross-linked short chains (which make for brittleness). Formulators of two-component finishes add chemicals called antioxidants that react with the broken chain ends, preventing undesirable cross-linking. Antioxidants, unfortunately, can’t be used with single-component varnishes, which depend upon oxidation for curing. As a consequence, single-component varnishes will continue to grow more brittle with time.
Lastly, film-forming coatings do not adhere well to teak. Teak is an oily wood, which doesn’t promote good adhesion; poor adhesion can allow moisture to enter through scratches or chips in the finish, whereupon it spreads under the film, causing an intact film to lift from the wood.
Some boat owners are willing to put up with a short-lived-were talking months now-teak treatment, if it’s easy to do. There are others who simply want the finish to last as long as possible without the need for attention. We tend to side with the latter group, though were concerned with how difficult life can be when the teak treatment finally does fail. Sanding down to bare wood is no fun and ought to be considered unacceptable. Maintenance problems are a strong consideration in our tests and reports.
Our basic testing program is the same as it has been for the past four years. We treat teak panels with each product, following manufacturers instructions, mount each panel on a rack and put them out in the New England weather. Weve been asked, “Why not Florida, or some other more severe location? Well, most of the products weve tested have failed in less than a year of our less severe weather. But because were now finding that some products provide multi-year teak protection up north, were seriously considering the use of a southern location, just to speed things up.
Of the panels weve exposed, only a few have survived: Honey Teak and Smith & Companys awkwardly named system-CEPS with Five Year Clear Topcoat-which represent the high-gloss systems, and Armada Teak and Cetol Marine among the semi-gloss products. In addition to these stalwarts, this year we added a number of new products.
We masked off a section of each panel with a piece of aluminum flashing so that we could see the difference between it and the portion of the panel that had been exposed to UV. We also used an awl to provide a couple of pinhole penetrations of each film to see if any moisture-caused separation occurred.
What We Found
On the continued portion of the test-up to 3-1/2 years now-we found that the two glossy survivors, Honey Teak and Smith & Co. CEPS, continued to impress. Both showed a very slight dulling, and the Smith & Co. product had darkened somewhat, but both looked very good…an amazing exhibition of longevity, we think.
The two semi-gloss survivors, Armada and Cetol, didn't fare as well; both showed discolored bare patches, with the Cetol holding up better than the Armada. To be fair, we werent following recommended maintenance procedures; a yearly re-treatment should have kept both products looking fine. What we wanted to learn was how long each product can last without reapplication. In both cases, we were able to restore a presentable finish by simply applying another coat. These four panels are out in the weather for continued abuse.
The new round of testing includes fresh applications of the four above-named products on larger 1′ X 2′ panels. To these we added 14 more products: Teak Shield Gloss, Teak Shield Semi-Gloss and Super Shield (all two-part fluorocarbon products); Penofin (an oil with UV-blockers added); Burgess HydroGuard (a water-based stain/sealer); Burgess HydroVarnish (a water-based varnish); WoodMate Semi-Gloss (a pigmented stain); WoodMate Gloss (a pigmented varnish stain); Woolsey Protective Wood Coating (a pigmented stain); Armada Semi-Gloss and Armada Gloss (a pigmented stain and a pigmented varnish stain, both reformulated since our last test); and a trio of not-yet-released products from Interlux (one water-based varnish, an oil-based semi-gloss and an oil-based gloss).
The rack of panels was exposed to the sun beginning in the first week of June 1998. Periodic inspections were made, with photographs and notes taken to record signs of failure. The panels were taken down briefly in January 1999 for closer examination and water bead testing.
The pigmented oil-based stains (we hesitate to call them Cetol clones, but thats what they look like) held up well. They all shared the same orange color, somewhat painty appearance and semi-gloss finish. The Armada and WoodMate showed the underlying grain a mite better than the Cetol and Woolsey products, but were not sure that theyll last as long (a previous version of Armada didn't in our previous test, but that may have been due to a problem Armada had with its formulator, that they say has now been corrected; the other two-WoodMate and Woolsey-were not previously tested).
Boat owners who love the look of traditional teak may be unhappy with the appearance provided by these products, but our experience has shown that they represent a durable, low-maintenance means of dealing with teak, as long as a glossy finish isn’t required. Application is easy (one component, low-viscosity liquids that brush on easily) and recoating is similarly easy.
Burgess HydroGuard is also a pigmented stain, but is water-based. Like the oil-based products, its easy to apply, and has a more pleasing brown color-to our eyes, at least-rather than the less appealing orange color of the others. Clean-up is easy, as youd expect with a water-based stain. Unfortunately, however, Burgess HydroGuard failed within six months’ exposure to the elements.
Weve never had much luck with teak oils in the past, but Penofin initially held some promise. At least its label did. The printed label claims 90% UV protection, and a sticker on the containers lid bettered that to 99%. Alas, it failed within three months, leaving the teak a dark brown, almost black color.
These are, in broad terms, glossy versions of the pigmented stains discussed above. While the semi-transparent pigments used in the stains seem to do a pretty good job of protecting the teak from the depredations of UV, they don’t seem to work as well in protecting the glossy film itself. In past years weve found that the glossy varnish stains don’t seem to hold up as well as their semi-gloss or matte counterparts. At the end of this first season, Armada Gloss was still intact while WoodMate Gloss failed in less than six months.
Burgess HydroVarnish, a clear water-based topcoat thats used in conjunction with Burgess HydroGuard, represents a somewhat different approach to obtaining a glossy stained finish. It has held up through seven months of testing, so far.
We tested three two-component products described by the manufacturer as fluoropolymers-Teak Shield Gloss, Teak Shield Satin and Super Shield. All of them are clear coatings. All require mixing a curing agent (called a crosslinker) to the product at a 32:1 ratio-an inconvenient ratio, if you don’t wish to mix the entire contents at the same time. Pot life is 4-6 hours, so its necessary to do some planning as to when youre going to apply the two coats called for. Teak Shield can be re-coated without the need for stripping.
None of these three survived six months exposure. This was a bit surprising to us, as wed heard some good reports about the products. Well trying them again this year with fresh batches of the products.
Smith & Co. CEPS/Five-Year Clear and Honey Teak behaved just the same as in earlier tests. Very well, indeed. Smith & Co.s system consists of an epoxy base coat and a urethane topcoat. Both the base coat and topcoat of the Honey Teak system are urethanes.
Smith & Co.s system again produced a gorgeous, deep walnut-colored finish. Honey Teak is more yellow/orange, with not quite as deep a gloss. Honey Teak is considerably more convenient to mix and apply because one mix of either the base coat or top coat will have a sufficient pot life for several coats. Smiths products have shorter pot lives and require much more frequent mixing.
Honey Teak claims to be recoatable without stripping. Smith & Co.s system isn’t. Both are very long-lasting, with high gloss and minimum maintenance.
And The Others
Interlux sent three not-yet-released products for testing-two varnishes (gloss and semi-gloss) and a single-component, water-based clear coating. The two oil-based varnishes held up pretty well, which is better than weve come to expect from varnishes. The water-based product has also held up well, which we find encouraging because water-based varnishes have fared especially poorly in previous tests. We will continue to test these products. If they reach the marketplace, well have some background on them.
We can’t recommend any of the products that failed our half-year test: WoodMate Gloss, Burgess HydroGuard, Penofin, Teak Shield (gloss or satin) or Super Shield. As for the others, well have to wait and see.
Meanwhile, based on our longer-term test, we can still recommend Cetol, if you want a semi-gloss finish (in previous tests, the Cetol gloss version didn’t last nearly as long). For a gloss, both Honey Teak and the Smith & Co. system will do a spectacular job, though were beginning to lean towards Honey Teak because of its less-fussy application schedule and its potential for recoating.
Contacts- Armada, Armada Coatings, PO Box 879, Havre de Grace, MD 21078; 800/336-9320. Burgess, Cetol Marine, Azko Coatings, 1845 Maxwell St. ,Troy, MI 48084; 800/833-7288. Honey Teak, Signature Finish, PO Box 1041, Port Salerno, FL; 561/287-6077. Penofin, Smith and Co., 5100 Channel Ave., Richmond, Ca 94804; 510/237-6842. Teak Shield, WoodMate, Noble House Coatings, 262 Progress Ave., Scarborough, Ontario, Canada M1P 2Z4; 416/332-9393. Woolsey/Z-Spar Marine Paint, 36 Pine St., Rockaway, NJ 07866; 800/221-4466.