Pondering Outdoor Finishes
Article - August 4, 2011
My Adirondack Chairs are reaching the final stages of construction and I’m sitting here enjoying a few swigs of YooHoo, so naturally this is a great time to ponder outdoor finishes. If you’ve been in the world of woodworking for a while, you probably already know that the only topic more confusing than finishing is outdoor finishing! There are so many products that make unbelievable claims and stretch the truth with confusing terminology and misdirection. I think a can of spar varnish once promised to make me better-looking. Well….you see where that got me.
So let’s break things down into the simplest terms possible. When it comes to outdoor finishes, you essentially have three broad general classes to consider.
Believe it or not, some woods are perfectly happy aging naturally. Woods that have a high rot resistance like cypress, redwood, and cedar, can actually survive for quite a while in the buff. In fact, some folks really prefer the natural aged color that these woods take on after years of enduring the elements. This method is not one of my personal favorites, but it is certainly something to consider.
Advantages: Easy to apply, because there’s nothing to apply.
Disadvantages: Wood will gray quickly (may not be a disadvantage to some) and most likely won’t last as long as a comparable piece with finish on it.
Maintenance: None. Until you get a splinter in your butt. Then you’ll probably have to do something about it.
On the opposite end of the scale, we have film-forming finishes. These concoctions attempt to envelop the entire project in a protective bubble, essentially blocking out the elements and preventing the absorption of moisture and deteriorating UV rays. Basically, its the finish taking the beating instead of the wood. Incidentally, paint would fit into this category along with clear coats.
Advantages: Thick protective barrier keeps the wood safe and offers a strong first line of defense against the elements.
Disadvantages: When film finishes fail, they tend to flake off and look like crap. So its not only bad for the wood, but the item can quickly become an eyesore if problems arise. Also, products in this category vary widely in cost and quality so its difficult to know which product is right for the job.
Maintenance: Re-coating every few years should keep the finish looking fresh, but continues to build the thickness of the film. And at some point, the finish may fail completely. The only option then is a complete re-finish. Yuck!
Oils represent something of a compromise. There are lots of different formulations out there but essentially the oil absorbs into the wood and dries within the fibers. After numerous coats, the wood has a decent amount of moisture protection while still maintaining a natural look and no film. If you don’t like the “deck rail” look of a thick film finish, oils are probably your best bet. Just keep in mind this finish will require more frequent attention in the future.
Advantages: Easy to apply. Wipe on, wipe off Daniel-san.
Disadvantages: Less protection and more frequent maintenance.
Maintenance: Possibly a yearly re-application. Fortunately though, you should never have to completely strip and refinish. Just clean up the surface and re-apply the oil.
So the point of this write-up is not necessarily to tell you what to use. Instead, I’d love to hear what specific products you’ve used in the past, what your climate is, and how the products have held up over time. I know there are lots of folks out there making outdoor projects who would LOVE to hear what you have had success with.
Want to learn more about outdoor finishes? Check these posts out:
The Global Warping Effect (Video)
Desert Outdoor Finish (Video)
Difference Between Spar Varnish and Regular Varnish
A Better Way to Apply Spar Urethane?