Darkening Cherry to Match Existing

Advice on using sunlight or UV to quickly darken Cherry wood, and some serious warnings about certain chemicals. April 9, 2007

Any suggestions on rapidly aging cherry? I'm building a fireplace mantle on a tongue and groove cherry paneled wall that was installed in the early sixties. I would like to match the existing cherry as closely as possible without staining, for fear that if stained, it will age to a noticeably different color over time.

Forum Responses
(Finishing Forum)
From contributor B:
I remember reading that lye will age cherry to look natural. Have to do some testing as to concentration and exposure time. I believe oven cleaner like Easy-Off is mostly lye. Used to use it to remove pitch and gum from tooling, also. Makes saw blades cut like new sometimes when it was just pitch friction.

From contributor G:
Make that a very dilute lye solution. You can find lye at old-timey hardware stores.

From contributor D:
I think Red Devil drain cleaner is lye and widely available at hardware and grocery stores. According to Jeff Jewitt's book on finishing, use .5 oz to 1 qt warm water, work from the bottom up, level out raised grain with synthetic steel wool and neutralize at the end with a solution of 3 tbsp of white vinegar to 1 qt water. It's drain cleaner, so wear gloves and goggles and be careful. I've been experimenting with chemical stains and I'm curious how well that works. The “iron buff" stain (soak steel wool in vinegar for 1-3 days and use the light colored solution to turn walnut gray to black) worked great.

From contributor C:
The lye thing works very poorly. The neutralization will reverse the effects. Skipping the neutralization (or doing it inadequately) will result in the eventual destruction of the finish. The best way is to expose it to direct sunlight for a few days. This can be faster than you would expect and is a pretty safe system. The sunlight treatment can work even through your finish, but is accelerated by leaving the finish for later. Significant darkening can occur in as little as two hours. Vastly faster than natural indoor aging. In the old days they used potassium permanganate or potassium dichromate... These are really too poisonous to have around, let alone use... so not a good option either.

From the original questioner:
Thanks everyone. Looks like I'll try the sunlight approach. There's no way that I'll be able to match the depth and richness of the 40 plus year old cherry, but I'll explain to my customer that it will gradually get closer in color.

From contributor E:
Contributor C is right about the potassium dichromate; it is also called bichromate, and can be found through ceramic supply stores. I have used this with good results. Use proper precautions when using it, and it will give you good results (sawdust is a known carcinogen, so let's not get off on a tangent about material safety in this thread).

Add about one tablespoon to a quart of warm water and wipe on the wood; you will see an immediate reaction that is quite attractive in some species. Allow to dry sufficiently, sand any raised grain, and finish to suit. Try some on a sample first.

From contributor T:
Nothing like sunlight. The sun baked samples below were set in direct sunlight for two weeks. The protected were kept in the dark. Note the significant differences in color resulting from the finish used. It was all one stick of cherry.

Click here for higher quality, full size image

From contributor S:
I use UV light with unfiltered UVA fluorescent bulbs. Works great on cherry and some other woods. Use when you’re not in the room, as it’s dangerous on your eyes. It will age cherry very quickly - sometimes just a day or two.

From contributor C:
Please take a good look at this MSDS for potassium bichromate. You are just kidding yourself if you think that its hazards are anything like those of sawdust. Take particular note of the hazards identification section and the long list that follows the statement "May be fatal if...". A minor mistake with this stuff can have major consequences... a big mistake will be your last one.

From contributor W:
I would steer clear of potassium dichromate - very clear of it. In this day, there is no reason why you should be able to obtain, let alone use, this highly toxic compound. It is a deadly heavy metal agent (chemical, not musical) and will burn your skin, liver and other basic organs into a leathery texture of cancer riddled, hard to dispose of badness. Speaking of hard to dispose of, try to get rid of the remaining amount of di/bichromate via your local waste hauler. Good luck...

If you want to age cherry, use double boiled linseed oil and a light solution of trade-sale ready wood dye. At least their dye has a minimal amount of chrome in it (as all wood and leather dye-stuff does...). Chromatic dye is hard to get rid of these days. The UVA/sunburn trick works well on cherry. Less high-level ozone = faster cherry burn!

From contributor R:
Contributor C, that sure was a nasty MSDS. Thanks for the heads up. I have read about this chemical in finishing books and from what I remember, they all mentioned how poisonous it was. Why is something this deadly still available?

From contributor A:
I would stay away from the lye idea and in case you don’t have two weeks to let it sun tan, this might be a good idea. I had a desk that the customer didn't want to look like a run of the mill kitchen cabinet. I took some yellow and orange and burnt umber aniline dye, cut it with lacquer thinner, sprayed it on the cabinet, no wipe, put about three coats on. You want it to look a little blotchy, then use a pigmented 15 minute wood stain, seal and lacquer. Then I ran some glaze in the corners, very subtle. It came out great. The best part of the job was when the painter called and asked "was that a Minwax stain you used, because I am trying to match some base molding for the same house and I can't seem to do it."