Discolored White Oak

[David Ortega Jr]

I used 8/4 quarter sawn white oak on a project. I carefully selected my 8/4 lumber to ensure it was close in color to some 4/4 material I used on the same project. After some assembly of the project I tapered the sides of my project by cutting off the sides of some of the 8/4 stock. I saw that the center of the boards were much darker than the outer shell. The medullary rays were also much darker in the core of the 8/4 material. This has resulted in boards with a splotchy and streaked appearance. I do not think it has to do with the tree absorbing minerals from the ground since the outer shell of these boards were absolutely consistent in color. It is not until the boards were "resawn" that I discovered the discoloration in the center. From the attached photos one can see the change in darkness from the outer edge. Even the rays change color. I have researched the cause of this without much success. The closest answer I found was the opposite problem; boards that are lighter in the middle due to improper drying process. This problem occurred in all three lengths of 8/4 material that I purchased at the same time. Any insights into this is much appreciated. And if anyone does have an answer to this, perhaps can provide tips on lumber selection to avoid this? Unfortunately I did not discover this until after the boards were already glued up in a preassembly stage of the project. I suspect that this happened after the stock was milled and during the drying process.

[Prashun Patel]

I suspect this is just some burning or burnishing from the cutter. Try sanding and applying some ethanol or mineral spirits to the surface to see how it looks then. I bet it goes away.

[Alan Gage]

I think you're looking at natural variations between logs. I recently put down white (bur) oak on my floors. It came from a large lot of rough sawn lumber I bought at a local auction. Some of the pieces, after coming off the planer, looked like they'd overheated and burnt (similar to yours). Taking lighter and slower cuts on the planer didn't make a difference and it didn't go away when sanded either. My floor is rustic with a mix of flat and quarter sawn ash and oak with plenty of knots so this doesn't look odd at all. But it would have stuck out like a sore thumb against run of the mill white oak.

A thought that just popped into my head is that it could possibly be reaction wood. I'm not experienced enough to say for sure if it is or isn't but that might explain it.

Alan

[Thom Porterfield]

You might investigate applying some oxalic acid (wood bleach), which I used on my white oak project to remove iron stains. It should even out the color somewhat. Then, consider applying a dilute dye stain (such as one of the water-based Trans Tint colors), to even out the color even more. Seal this dye before applying other colorants or finishes. The dye colors the areas of the wood between the medullary rays more than the rays themselves, thus enhancing the rays in the finished piece.

[johnny means]

Yeah, that looks like burning to me. It's very hard to sand out of white oak and is very easy to get in white oak. what did you cut it with?

[David Ortega Jr]

Thanks for the replies so far. The photos were taken after the 8/4 was cut on a band saw, flattened on an 8 inch jointer with a spiral cutter head, and then sanded. So definitely not burned. Although white oak does have color variances, even within the same log, I find it suspect that there was absolutely no discoloring on the outer surfaces of each board, just in the centers. Perhaps I will try some wood bleach as suggested by Thom Porterfield.

[Prashun Patel]

Have you tried testing the finish on your pieces. Imho you are not going to notice it after finishing.

[David Ortega Jr]

Prashun, you are right. I typically use dark water based dyes to finish QSWO projects and they generally hide color variances. However, I have a client who ordered a piece but wanted a light colored natural finish. Thus, the disappointment in finding dark patches after the fact. Fortunately he changed his mind and wants to go dark on the color. I ordered oxalic acid to try it out. There are a couple pieces that have pretty significant splotches of dark that may show through after finishing. The learning process of woodworking and finishing are never ending . . .

[Andrew Seemann]

The darker part could be burning and/or it could be just natural variation. It looks like those parts of white oak where it is hard as concrete. I sometimes wonder if it is just a section with more deposits in the heartwood.

[David Ortega Jr]

JUST RECEIVED THIS REPLY ON THE WOODWORKING NETWORK FROM GENE WENGERT WHO IS AN EXPERT IN THIS FIELD:

Gene Wengert replies: The core color is darker because it was still wet when the lumber was put into the kiln. So, the outside shell was air dried at cool temperatures and probably at a reasonable speed. However, in the kiln, the wet core was dried at a hotter temperature than air drying. Differences in drying speed result in differences in color. As far as I know, there is no cure, other than using stains in finishing.

[Thom Porterfield]

I tried to match the color of two QSWO from different planks using oxalic acid. It made the differences less, but didn't change the character of the wood. If that darker section doesn't lighten with several "semi strong" applications of the acid, I think you're stuck with darkening everywhere else to match. Good luck.

[David Ortega Jr]

Thom, I ordered some oxalic acid to try it out. Got impatient because the shipping was going to be longer than normal. I ended up using a dark water based dye and the color differences are almost imperceptible. Originally one of my pieces was going to be natural in color at the customer's request. Lucky for me he changed his mind and I was able to use the dye to even the color out.

[Thom Porterfield]

Good job. FYI, I found a product at ACE hardware called Wood Bleach which is a concoction of primarily oxalic acid. Comes in a container the size you 'd buy cottage cheese in. Mix the stuff, which is like coarse salt, in warm water.
As I said earlier, I completely removed stains that appeared on my project due to some metal filings that went astray in the shop. Saved the day. I also tried taking some of the redness out of red oak plywood I used for shelves. It made the red oak less red, kind of pink, actually, but then using the same dye/glaze combination I used on the white oak. Other than the grain pattern, which is condiderably different, the color is the same.
I'm glad your project was saved by your client's change of heart.

[David Ortega Jr]

Good to know. I have a mix of red oak and white oak in my living room. Very hard to tell apart once everything is dyed and top coated. My white oak projects evened out quite a bit. Not perfect, but I am my biggest critic. Will definitely try the oxalic acid if I encounter this again.