I am making an Adirondack chair out of African mahogany, but I’m not sure what type of finish to use. I live in the Los Angeles area. We get mostly SUN here — no snow and hardly much rain. I have been woodworking for about 50 years, but all of that was making indoor furniture, so I am not sure if a stain would be my best choice for the chair or something else. I want to keep the look of the African mahogany. Any help would be welcome. – Brian Finnegan
Chris Marshall: Finishing outdoor furniture is a common reader question we get at the magazine, and it’s a sensible one. After all, once you’ve put time and effort into designing and building a new Adirondack chair, who wouldn’t want it to last as long as possible and look as good as the day it left the shop? But sunlight and wood aren’t a marriage made in heaven. Add occasional moisture to the equation, and that just complicates things all the more. UV sunlight will eventually fade the wood’s color to silvery gray unless you are determined about maintaining the finish, and both water and sunlight will typically compromise a hard film-forming finish like varnish and cause it to crack and peel.
So, my advice? First, since you mentioned you want to keep the “look” of the mahogany, I would stain the chair with a tinted deck finish to prevent the wood from fading to gray. You’ll have a bunch of nice stain colors from which to choose, and if you go with a semitransparent formula, you’ll be able to see the wood grain through the color. If the chair starts to look dry and faded, just the clean the wood and re-stain it. Second, find a shady spot for your chair, and you’ll prolong that nice stain color. I would skip a film-forming finish altogether, to eliminate the possibility of having to strip and refinish it someday if the coating fails.
We’ve written on the subject of exterior finishes before in the eZine, so you might find the following two links helpful. Here was a question about the best finish for an exterior door (click here). And this post might be useful, too: it’s a more general overview of exterior finishes (click here).
Good luck with your chair project! African mahogany is fun wood to work with, and it will make a handsome-looking Adirondack chair.