Well, it is that time of year again, time for making Christmas presents. My first Christmas project is also my first experiece with cherry stock. All went well until I applied the finish:
The entire project is constructed from the same 14″ section of cherry stock (4.5 inches wide). There was no ostensible color variation in the rough stock or at any time, up until the first coat of finish was applied. I decided to try pure tung oil, figuring “what could go wrong.” Well, some parts from this same piece of wood turned significantly darker that the rest (and not between end grain and long grain), with distinct demarkation between the lighter areas and darker areas. What happened? Is there any way of evening out the color now? (e.g. exposing the cherry to sunlight to darken it) and is there any way to anticipate this problem in a particular piece of stock in advance?
Replies
I work with Cherry all the time. It is very susceptible to blotchiness. Usually, if you put shellac on first, it helps control it. The shellac absorbs the oil evenly. I'm not too familiar with Pure tung oil, so I can't tell you what can and can't be done to rescue it. If it hasn't penetrated too much, you can sand it off and start over. If this is not an option, the sunlight will definately darken the cherry.
In the future, I have had excellent results with General Finishes Seal a cell, which is a tung oil/poly and blo (i think???) mix. It doesn't blotch like other finishes will.
Jeff
If this is distinct areas, not just blotches, then you may have missed the distinction between heart and sap wood. Not so hard to do if the cherry was light toned to begin with. Not much that you can do if that's the case. The heart wood will darken considerably more than the sapwood, increasing the contrast.
If this is basically blotches its hard to avoid with cherry. I like to think of it as "figure". A good example is to look and the Thom. Moser furniture and note that some of it shows distinct blotchiness. Then look at the list prices and think that blotches are not all that bad.
You could heavily sand the oil out, use a "conditioner" before the oil, and perhaps use a gel stain/finish that doesn't penetrate much, and consequently doesn't blotch much.
Could be that the cherry had been steamed by a processor to even out the color between sapwood and heartwood.
If a wood has any propensity to color unevenly, it will do so whenever a liquid is applied that soaks into the wood. Cherry, because of the way the grain waves throughtout the wood--which gives it the interesting grain patterns--will absorb a liquid unevenly and cause an uneven color. Any oil has a little color to it so this color will be darker or lighter depending on how it is absorbed and then how it reflects the light.
One way to significantly reduce this uneven coloring is to reduce the absorbsion of the finish in those areas that tend to absorb more finish. A 1# cut of shellac will tend to work fairly well. Apply it, let it dry and then lightly sand it with 320 paper. Then apply the oil. Test it on some scrap as you sometime need to adjust the cut of the shellac depending on the wood.
Many professional cabinet makers will first apply a coat of amber dye stain to somewhat even out the coloring before applying a finish. This can work well too but needs to be tested.
Finally, you can learn to love cherry for it's uneveness. It's this uneveness of color that can cause it to somewhat shimmer as you walk by it.
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