Know-How

To Varnish or Not?

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Dorothy Parker once famously remarked: “I hate writing; I love having written.” I feel the same way about varnishing. Nothing flatters a boat more than the glow of well-varnished wood, but to bask in that glow, someone must suffer through the process of preparing the wood and applying the varnish.

Almost all woods other than teak will weather and eventually rot if not protected from the elements. Paint is the most effective protective coating, but if you paint wood, all you see is paint. Varnish protects wood without hiding its inherent beauty; ten coats of glossy varnish can transform a merely interesting piece of wood into something achingly beautiful. Dorothy Parker’s sentiment applies: everyone loves varnished wood. It is the varnishing we hate.

Unfortunately, varnish is your only choice if you want to protect exposed mahogany without painting it. As for teak, it can stand the exposure, but due to pollutants in the air, it will more likely turn black than silvery grey if not treated. You can bleach and scrub it back to its original golden hue, but each scouring removes a layer of wood. Exposed screws and popped bungs in teak woodwork are nearly always due to excessive cleaning, not weathering.

What Is Varnish?

Varnish is essentially paint without pigment. It is broadly defined as a transparent hard coating, “hard” being the key word. It is the solid left behind when a liquid mixture of oil and resin dries. In traditional spar varnish, the oil is tung and the resin is phenolic. Today there are many other formulations on the market, but no other transparent single-part coating is more durable in the marine environment than spar varnish.

Most sailors don’t care what’s in the can as long as it goes on easily and lasts a long time. Still, in deciding whether to embrace or shun varnish it helps to know that the can contains some kind of oil, some sort of resin, a quick-evaporating solvent, maybe a drier to accelerate the process, and an additive or additives that boost ultraviolet protection.

Over the years I have tried several different varnishes, most to good effect. I do have a favorite, but will not name it here lest I seem unenlightened to devotees of other brands. I will offer this: you can’t go wrong in terms of aesthetics and durability if you select a spar varnish that has a tung oil and phenolic resin base along with UV inhibitors.

Easier Alternatives

Because varnishing is such a pain in the transom, chandlery shelves are crammed with other products promising similar protection with less effort. Paint sellers also offer an array of transparent wood finishes that are purportedly easy to apply. In fact, virtually all these alternatives are both easier to apply and reapply. Unfortunately, their durability ranges from fleeting to seasonal, with some notable exceptions.

Oil is the easiest alternative and the shortest-lived. The idea is that it restores wood’s natural oils, which, take note, sounds a lot like marketing for daily skin care products. Teak oils used to be either linseed oil or tung oil-based, with tung being the preferred choice, but you’re just as likely to find castor, palm, lemon and even synthetic oils in today’s chemical concoctions. Most also include resin (to extend the product’s life), solvent (to improve penetration) and UV additives.

Teak oil looks nice when fresh, but it washes away at sea or carbonizes and turns dark at a dock. Like any oil, it also traps dirt and fosters mildew. Teak oil rarely lasts more than a few weeks, and its lifespan declines in lockstep with your latitude. For teak decks, oiling can be the best alternative to bare wood, but when it comes to brightwork, the cooler, cleaner, and more overcast your environment, the longer your teak oil will last. In sunny climes, oil appeals only to those who prefer short but frequent maintenance sessions.

Sealers, sometimes called “treatments,” typically contain the same core ingredients—oil, resin, solvent and UV additive—but the ratio of resin to oil is higher. This is to prolong the product’s lifespan, and sealers on the whole do last longer than oil. But if you fail to maintain it properly, the additional resin makes prepping the wood for a fresh attempt more difficult. Sealers are best applied to fresh teak or to teak that has been freshly oiled. You can, if you like, concoct a perfectly serviceable sealer yourself by thinning down spar varnish by 50 percent with turpentine or mineral spirits.

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