As usual, click any photo to bring up a larger version.
I am taking many precautions. I've done my homework. I am accepting the risks to work with it.
I'm working on a project right now that I am building out of black cherry. I would typically use some sort of an oil finish on cherry (like Circa 1850 Tung-and-Teak, or maybe Tried and True) or if I wanted a film finish, then I would apply one or two coats of shellac followed by Varathane. This looks nice, and ages over time to a gorgeous dark natural cherry look.
However, several years ago I came across a document on a woodworking forum in which a woodworker used a solution of lye to accelerate the darkening of cherry. The results were gorgeous, and allowed him to produce brand new cherry baseboard that looked like it was already six-ten years old, and nicely matched the dark hardwood flooring that he had already installed. I quickly did some research and found a few other documents that also outlined similar experiences.
Basically, with time and exposure to UV light, Black Cherry will naturally age to a lovely reddish/brown colour. But you can jump-start that process by wiping down your lumber with a solution of lye. This can be quite useful if you are repairing an older cherry piece and need to fit in some new wood, or if you are trying to match another project, or if you simply would like to get a head start on the natural darkening process.
I finally got around to wanting to give this a try on one of my own projects. So here is a photo essay of trying this out on some sample boards.
I had read that the lye wash would raise the grain, but that you need to then be careful when sanding, as the colour is not very deep. I thought to try pre-raising the grain to avoid this if possible.
Note, I googled up a few other references to people doing this, and they also used roughly those proportions. I actually used 1/2 Tbsp to 1/2 pint of water. Add the lye to the water (NOT THE REVERSE), and always add it slowly while stirring.
I was not happy. I was close to throwing in the towel. I'd thought that I'd followed all the guidelines, but I was not at all liking the results. Maybe I should just stick with the familiar?
So I went back to Google and searched more online... I found another reference to this which contained a hint... The vinegar wash might have been the culprit.
I tried one more test board. (Test #2) This time after the Lye wash I left the board to dry for over an hour. Only then did I come back and wash it with the vinegar solution. Here is an outdoor photo showing the new board inbetween two of the old boards. On the left is the blotchy board. On the right is the control. The new center board shows a much more even colouration.
Next, I applied two coats of Varathane. I usually use this product when I want a film product, such as for a bookcase. I've been using it for 15+ years, and have the technique down for getting good results.
Here is what he explained to me:
In his experience, after the Lye solution dries on the board, the cherry looks "like dirt". (I agree it looks dull.) However, it lights up once you apply the finish. Also, depending on the finish I was using, I could even skip the vinegar wash. With an oil finish, like a Tung oil, he recommends the vinegar wash. With a lacquer or polyurethane finish, he suggested I could skip the vinegar wash.
Time for Test #3. Here are the two board after being washed with the Lye solution and left to dry indoors.
Disclaimer: I am getting better, but the colours in this photo are a bit off. It is a touch less red, and there is a bit less "depth" in the grain on the left of the lefthand board than in this photo. Still, lovely.
I plan to keep giving these boards a "suntan" -- a few hours outside in the sun each day -- for several days, to see if that makes any difference in these results.