Exterior Clear Finishes
How to Protect and Beautify Your Outside Woodwork by Michael Dresdner
Wouldn't finishing be easy if we could use the same coatings on everything we make? The sad truth is that furniture forced to live out-V x\ I doors all year long takes a lot more of a beating than its cousins inside. So, when choosing an exterior finish we have to consider not only appearance but also the effects of the sun and the weather.
No finish I know of will stand up to the ravages of weather indefinitely. The best you can hope for is a few years of good looks, along with the promise of easy renewal when the time comes to rejuvenate the finish. Depending on your definition of "good looks," your choice is often between the ease of rejuvenating the finish and the length of time between facelifts. To help us decide, let's look at the relative merits of different exterior finishes—from the simplest to the most complex.
any case, I've seen pieces older than I— and I'm 45 years old—that time and the elements have not yet destroyed.
Oils: Hardier but Harder
After an naturel, the simplest exterior finish is the same as the simplest interior finish: oil. Several wiped-on coats of linseed oil (raw or boiled) or tung oil will add depth and beauty to the wood and help it shed water while maintaining the wood's color. To keep the finish healthy looking, clean the piece with a bit of naphtha-soaked steel wool or Scotch-Brite™ and re-oil once or twice a year. It's a lot of effort spread out over years of casy-to-manage installments.
Wood "treatments" such as Thompson's Water Seal and other silicone products are fine for protecting decks, but they are not finishes. While they help the wood shed water for a period of three to six months, they do little else to protect the wood from stains or graying.
Similar to oils—but with just a tad more protective "oomph"—are the liquid or gel type wipe-on oil-based varnishes. These are combinations of oil and oil-based resins, such as alkyds and polyurethanes, and they're generally as easy to apply as straight oils. Although wipe-on varnishes also need frequent rejuvenation, the process is the same simple one as for oils.
Another rung up the ladder are the brush-on varnishes. These film-type coalings add real gloss as well as protection. They will last at least a year or two before recoat time, depending on the exposure and finish depth, but rccoating will be more work. Choose either a spar varnish (tung oil and phenolic resin) or an exterior (aliphatic) urcthanc and apply at least three coats. When the gloss level begins to fade it's time to recoat. Clean and lightly sand the surface before brushing on another layer. Don't let
The cheapest and easiest way to finish exterior projects is to put nothing at all on the wood. For many woods and designs, this is the best option. Cedar, cypress and redwood weather nicely without any help from us. Mahogany and teak—two woods that arc traditionally finished with film coatings—develop a charming, silvery patina that is as elegant as the white beard on St. Nick. While some may argue that a finish helps wood to survive longer, I feel it is legitimate to let wood age and die gracefully as nature runs its course. In
A clear choice. There are several ways to keep outdoor projects looking great and protect them from the elements. All require routine maintenance.
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