Cherry response to UV over time

[mark mcfarlane]

Cherry darkens over time when exposed to UV light.

> Can anyone share their experience with how this darkening rate changes overt time, e.g.

- after a year in moderate sunlight it gets about as dark as it will get,...
- 10 years later and it is still noticeably getting darker,...
- 20 years later and there is no evidence of grain left

Just looking for some anecdotal experience, or some science if you want to share.

[John TenEyck]

There's no correct answer to this because it depends upon both the wood and the intensity of the exposure. In my own house I have a cherry side table that gets only indirect light exposure. It darkened for a year or two and, as far as I can discern, has remained unchanged since then for more than 25 years. I also can attest that cherry will turn almost pale white with enough direct sunlight exposure. I was in a house in Germany where the vertical cherry balcony boards received direct sunlight through some floor to ceiling windows. After 15 or 20 years those boards looked as white as hard maple.

John

[Warren Lake]

this is over 40 years ago. Two coats of Watco Oil at the time then never touched again. Living room but not close to the window other side of the room.

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[mark mcfarlane]

Thanks John and Warren for sharing your experience.

[Dennis Jarchow]

Here is a picture of our cherry kitchen cabinets when I was setting them 18 years ago and then today. The kitchen has a southern exposure and three large windows and a patio door. Lots of sun.

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I am building a bar and cabinets right now for our basement out of cherry and have been surprised by how differently some of the changes. I set some of the freshly planed lumber out on our deck in the summer sun for three or four days with some masking tape on it to see the difference and got almost zero change. The cherry plywood was stacked in the garage with almost no sunlight and started to show very noticeable lines where sheets overlapped in just a couple days.

[mark mcfarlane]

Thanks Dennis for the pics and contribution. Beautiful cabinetry.

[Mark Rainey]

Several of my cherry pieces have had indirect or little sun exposure and they seem to darken mildly to moderately over a year or two and then slow down or even stop getting darker. I am not seeing any dark cherry color.

[Mike Henderson]

My ezperience is the same. Cherry gets darker in the beginning but then stops darkening.

Mike

[mark mcfarlane]

My ezperience is the same. Cherry gets darker in the beginning but then stops darkening.

Mike

This is what I hoped to hear, although I understand there are many factors.

I built a bunch of cherry cabinetry with two coats of garnet shellac + ARS topcoat that hit the perfect color after 9 months of fairly heavy UV exposure from an 8' *18' clear glass window along with 3 other fairly large windows in the room. I had 3M Prestige film put on all the windows last week which should eliminate 99% of future UV so hopefully the color will stabilize close to where it is at.

Thanks Mark and Mike for responding.

[Jim Becker]

Different trees will have different reaction time to UV and oxidation. I do agree that there is 'that point' when the color effectively stops changing but even that can be variable to a certain extent. While this discussion focuses on cherry which is well known for getting darker, it applies to most wood species...and a few, like walnut, get lighter over time from the same UV and oxidation. It's one of the things that makes "matching" new trim work in an older home so challenging!

[Jeff Roltgen]

Have a cherry desk I built over a decade ago. Last 5 years, it sat with one side about 2 feet from a window that never had the blinds drawn. Bleached the transfast dye and natural color almost completely out - very blonde on that side now, unfortunately.

[Dennis Jarchow]

I found this over on woodweb some time back. It is an image of cherry color change over time and how that is impacted by the finish. It is all one board that was cut into smaller pieces, then the pieces were finished with a variety of different topcoats. One piece of each finish was exposed to light and the other was protected.

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[mark mcfarlane]

Thanks Jeff and David for chiming in. I did some of my own Transtint tests and saw a similar bleaching effect.

[Lee Schierer]

I have some cherry that was harvested over 70 years ago that is dark all the way through. It doesn't get any lighter if you sand the surface, resaw it or crosscut it. Here are two pieces made from it.
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[John TenEyck]

I have some cherry that was harvested over 70 years ago that is dark all the way through. It doesn't get any lighter if you sand the surface, resaw it or crosscut it. Here are two pieces made from it.
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I used a piece of cherry that was probably 50 years old and had been stored in the attic and it was the same as you described - dark all the way through. My take on it is that the wood was fully oxidized; over all those years oxygen diffused to the center of the board and changed the color beyond what UV exposure can do at the surface. It would be interesting to take a piece of that wood and set it in the sun to see if it would bleach back out. I'm betting it would.

John