Correcting Sun Striping in Cherry

Techniques to re-blend sections of a Cherry piece that show the effects of sun and shading. July 2, 2008

Some months ago, we installed a cherry cabinet with 1 1/2" adjustable shelves, stained and lacquered. There is a lot of UV penetration in the room. Recently, the clients have moved some shelves and now see light horizontal stripes where the shelves used to be. I've consulted a few finishers, most of whom say the stripes will darken over time and blend back in. Has anyone had to deal with a similar situation?

(Finishing Forum)
From contributor C:
Sure - happens a lot. Must be an open cabinet - am I right? If you leave it long enough it will finally blend in, but is the customer patient enough to wait that long? Are the shelves going back in at a different level or are they not using them anymore? Is this purely a natural cherry finish, or have you colored it - stain/dye etc.? One time I had to tape and paper an area and hit it with UV light to blend it in - 300a V light - to get it done quickly. If you try toning it or touch up, it will then get darker than the rest.

From contributor R:
Your posting says that you stained and lacquered, so I guess it's not a purely natural cherry finish. The solutions are rather simple and won't require any state of the art voodoo. First off, your customer can live with the color difference. This would have happened even if you did a purely natural cherry finish. Second, if your customer really is insisting that those stripes go away, just remove everything in the bookcase which does include the shelves and let nature take its course. Eventually, the color might just catch up to itself and blend in better than it does now.

From contributor K:
Take a piece of unfinished cherry, place a piece of 2" masking tape across the middle. Then place out in direct sunlight for only one day. Ask the homeowner to uncover the tape. They will see what you mean.

From contributor P:
Sunlight (UV) will darken the wood that was previously covered. It will take a while for it to blend in, but as stated, it will happen. I did an experiment on this very problem a few years ago using cherry with a clear finish. It took weeks for the lighter wood to darken as much as the wood that was exposed to sunlight.

From contributor G:
Contributor C, you have mentioned a "300a UV light" several times. What model is a good purchase?

From contributor C:

I use the portable light and also have a bench light. You will see many listed - they specify which is best for paint and coatings. 300aUV is best for weathering results. Some can oxidize a wood surface such as cherry in an hour or less. I only recommended it because taking down a cabinet and moving somewhere for sunlight to create the same results seems unnecessary when it can be accomplished in an hour without the extra labor. I've also used it in shops on occasion for quickly blending out partially oxidized panels carelessly stacked where part of the board was oxidized - here again by taping off and exposing the unaffected areas to the UV, or also for quick oxidation of entire panels in large operations where that look was desired. But that cost mucho money - lots of lights needed, spaced close together. The operative word here is quick - if your customer does not care about how long it takes to catch up, you can still do as others have posted. I'm usually called in to be a problem solver, and my clients want fast results if possible.

PS: Check the progress of oxidation every 10 minutes to see how close it has come. Do not just assume it takes a set amount of time. This is not something you can just walk away from. Stay on top of it until it's where it needs to be and wear protective UV glasses also!