Walnut Plywood for Wall Panels
They really like the look of walnut with just a clear coat finish and no stain, but I wondered how the actual walnut plywood (with its five strips of walnut veneer per panel) would look with just a clear polyurethane coating? Iím specifically wondering if the lines of separation between the five strips of walnut veneer will be too prominent with just a clear coat on a 4x8 sheet on the wall. Does anyone have any experience with just a clear coat over a piece of walnut ply?
From contributor K:
If the walnut faces on your panels are constructed correctly the seams should be very inconspicuous. You will be able to discern the different components only because the grain direction of each adjacent flitch. This is assuming that you are working with book matched faces and flat cut walnut. If your faces are made out of quartered walnut you would have to consider the possibility of barber polling which makes the veneer face look alternating light and dark from flitch to flitch across the veneer face. The picture is a close up of a bookmatched flat cut walnut. There is no finish on this sample but in my experience the finish doesn't make the seams show any more than you see there.
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From contributor L:
The color of walnut changes greatly with time, and especially with UV light. It will be very yellow in the years to come. As to the mentioned barber pole effect that is due to the practice of flipping every other leaf over during manufacture, as in book matching. Slip match won't display the barber pole affect but will look more like a series of matching boards. The only way I can think of the get rid of the seams between leaves is to get one piece rotary faces. Not likely to be easily found.
From the original questioner:
I went and looked at a sheet at a local hardwood supplier and I could see the distinction pretty clearly between the different vertical grain slices of veneer, this was on an uncoated piece. The plywood was A-4 graded. Five vertical grain veneer slices and the walnut side looked nice but I thought the veneer slices were more distinctive than I had imagined they would be (again Iíve never seen a high quality piece of walnut ply so I didnít really know what to expect).
However, this particular piece of walnut plywood is labeled as imported and they only have imported sheets in the 1/4" thickness. They offered USA made in 1/2 and 3/4 thickness. Would a USA made piece of 1/4 ply provide a more uniform appearance, or are the imported pieces as good? I'm going to need about eight full sheets and if USA made ply will provide a significantly better look I will look into finding a local (Seattle) supplier that has it in 1/4 inch. Also, on the walnut yellowing with age due to UV light I was planning on spraying these panels with automotive grade 2 part polyurethane clearcoat. That has excellent UV protection. Does a UV protector based clearcoat prevent walnut from yellowing with age?
From contributor K:
A spliced veneer face will always have seams, nothing will really change that. A well constructed face will minimize the visibility of those seams. A book matched veneer face exploits those seams and makes a symmetrical pleasing appearance. The least visible seams would be on a quartered walnut slip matched sheet with perfectly straight grain. If there is any swing to the grain in the quarter cut flitch then even on a slip matched veneer face the seams will become more conspicuous. As far as which is better, Chinese or American, that will be for you to decide. Whichever one gives you what you need. I've had issues with other Chinese plywood in the past as far as warping, de-lamination, and inconsistent size. If the product does not look like you need it to then it is wrong no matter where it is manufactured.
Nothing will stop the walnut from changing color. The UV protection in your finish is just an inhibitor and they will significantly slow the color changing process but they will not stop it. The change will be gradual and you'll only really notice it is if you move an object that was blocking out the sunlight completely on the walnut.
From contributor K:
That is pretty much all you can do, is get a sample to your customer and see if it works for them. I have also found with some Chinese plywood that the faces of veneer can be very thin - so thin that the substrate starts to show through the veneer. Inspect your sheets.
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