Expert: Greg Scholl - 6/2/2009

Question
Greg,

I am refinishing a fine mahogany front door which has been partially exposed to weather for twelve years.  (The lower third of the door has been exposed to rain splash and to some limited sun.)

The upper portions, which were more protected, were a deep reddish black.  The lowest third was gray to white.

So far I have sanded with medium sandpaper and have watched the wood come back to an apparently uniform lovely light red.  I can't believe my luck.  There seems to be no cracking or splitting of the wood and the gray/white parts look the same to me as the parts which were previously in much less weather-damaged condition.

I intend to continue with the sanding, moving down to much finer grades, then apply two coats of Minwax indoor/outdoor clear semi-gloss helmsman spar urethane.

Does that sound good?  Are there other steps you would recommend?

The door is well worth any extra effort.  I want it to look good.  Besides, it is a huge, solid thing that weighs over 300 pounds and it would be very expensive to replace.

Directions on the can of urethane say "if desired, apply stain... to unfinished interior wood surfaces."  The word "interior" makes me think it might not be a good idea to apply stain to the exterior side of the door.  In any case, I kind of like the lighter red color that has emerged, like freshly sanded cherry.

Thanks for your very valuable thoughts!

 Stephen in Annapolis, Maryland


Answer
Hi Stephen, do you know that the door was finished with Spar? I hesitate to recommend coating an old Spar finish unless you know what it is, and are absolutely sure it's sound and adhering well. The best course of action, and the one that will turn the door all one color is stripping off the old finish down to the wood with chemical stripper. (or paying someone else to do it.)I would also not recommend staining the exterior of the door. The natural color of the Mahogany should suffice....but if not stripped, it likely won't be even, or as dark as it should be, because of moisture exposure, sun, mildew,etc. I dislike Spar, as it's a film finish and prone to failure like what you're repairing now. I am a bigger fan of a penetrating finish, especially for exterior Teak, Mahogany, etc.These finishes soak into the wood fibers and harden from within, building from coat to coat to give you a hard but flexible finish that's durable,breathable, and re-coatable.They won't peel or flake. It's imperative to make sure to thoroughly coat the end grain of the door with at least 3 coats of whatever you decide to use to keep it from wicking up water. Post back if need be and best of luck.- Greg

http://www.waterlox.com/desktopmodules/fathomecom/Catalog/ProductDetail.aspx?ct=...

http://www.cabotstain.com/products/product/Australian-Timber-Oil.html