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Color variation with clearcoat okume
I'm finishing up a Skerry, have just clearcoated part of the interior, and observe huge color variation in the result. The floor was originally glassed about a year ago and has the nice color tone you'd expect from okume. The newly coated okume seats, bulkheads, etc. are now all really DARK, aslmost as if stained. Not a great look... Does anybody have an idea about why this is? My current guess is: the Skerry has been sitting in my basement for a year and it's a humid place in the summer, so maybe the acquired moisture content of the bare wood interacts with the epoxy(?) Or maybe the epoxy I'm using (MAS slow) is just too old. It'd be nice to have a good idea on this before I sand off the new coating. Thanks for any suggestions!
5 replies:
RE: Color variation with clearcoat okume
I received my Skerry kit this past May and was glassing the exterior by the end of June. In October I epoxy coated the seats and have noticed that they are darker than the exterior and interior and I gave the seats a thorough sanding prior to coating. I believe that no one will notice that and probably no one will notice the difference on your boat but you. The wood may, in fact continue to "adjust" according to how long it is outside exposed to the elements and sunshine. Then it may not. I realize the varnish blocks UV rays but I'm not sure that is the only thing affecting the wood color. There may also be natural variations in the color from one piece of wood to the other.
Henry
RE: Color variation with clearcoat okume
It's called oxidation; leave two boards not exactly lined-up and put them undisturbed up in the garage for a while. When you move them apart you will see a slight darking line where they were slightly askew. Run a piece of pauduk thur a planner and it is an ugly orange,few days later it is turning a beautiful burgandy--oxidation!
RE: Color variation with clearcoat okume
Update - I purchased some new MAS epoxy and experimented on some scrap okume from the same environment -- new epoxy vs. old, light prior sand vs. heavy. All 4 areas looked the same afer 1 coat -- nothing made much difference. The best evidence on this issue is from an unfinished scrap piece of okume standing on edge in the basement, which has a bare concrete floor. The area near the bottom edge was noticeably darker (bare wood) than the rest. Conclusion: over time, unfinished okume absorbs moisture in a humid environment and darkens on its own. This is darkening is difficult to remedy through sanding.
RE: Color variation with clearcoat okume
When all else fails, a good coat of paint will improve almost any okoume.
-Wes
RE: Color variation with clearcoat okume
» Submitted by Lew - Fri, 11/11/11 » 11:00 AM
Do you have any uncoated scraps left over? Sand down a portion to clean wood then wet the sanded & unsanded areas and see if either turns dark as well. I don't think old epoxy is the culprit. I think moisture, dirt or sun is the cause.
FYI- Hiding the ugly: I had success with my most recent build with a translucent aerosol spray stain/varnish from Wood Crafters. It will make the area darker but could add some nice color of your choosing. If interested, I can get the name of the stuff tonight. Went on quite even.
Lew