Oak Stained and crooked


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24 May 2020
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Hi, I bought oak PAO from a local timber factors and it looked fine.
I was was short a 2 metre piece and when I bought it (€43), it had yellow stains on one side that I could not sand out.
It also had black marks that I couldn't sand out and it was not straight.

This was my first real project so I didn't want to complain, not knowing what was acceptable.
A day after finishing. I noticed that the wood looked like it was about to split (not drilled at this point), see picture.

Can I ask, would the yellow stains normal/acceptable?
Would the black stains be acceptable?
Is the cracked wood and the bend acceptable for PAO?
The wood wood cost €580 in total and I would expect more at this price.
(Pictures attached)
Unfortunately, I cannot remove the piece (see final picture) without destroying the bench.

Andrew, Coolock


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I don't know what PAO means.

The yellow stains are fungal, and they shouldn't be there. They are the result of over-cooking the board in a kiln, or, believe it or not, allowing the board to get too hot whilst air drying. Yes, with global warming, not only can that happen, but it is happening more and more. That is cause for returning the board. However, it's too late once you've cut it up and worked it. The good news is that it fades to nothing over time. If you have a decent relationship with the yard that sold you the wood, let them know and they might offer you a discount on your next purchase. My woodyard are going to give me 3 or 4 boards FOC next time I buy anything from them, because of some similar fungal stains in £1000+ of oak I bought a few months ago.

The rest of the stuff is just what you expect from wood, and the very best reason for selecting your own boards. I would never ever buy timber without picking it myself......it's just about rule number one of buying wood. If you take the risk of buying sight-unseen, then this is what you get.

One of the lessons you must learn from this, apart from selecting your own wood, is to be really observant of it as you select what goes where in your project. You should have noticed that it was checking before you cut it and used it.

You cannot expect timber to be straight. Every piece of wood you buy you should sight first, but if you do end up with a cupped, bowed or twisted ("in wind") piece, then you need to develop the skills to deal with it which include using it in short lengths or widths, flattening it adequately, and siting it in less important places. This is also why you MUST over-order for any project. Whilst building up your stocks initially, try to buy 20% more than you think you'll need. Even with lots and lots of stock in various stores, I still buy 10% more than I need for each project. You have to have spare so as to be able to work around boards that have an issue.

Let me finish be re-iterating that the primary lesson from this is to select your own boards. Take a scraper or a block plane with you to the yard, as well as a tape, a piece of chalk, and a straight edge. Be prepared to spend a couple of hours looking through a whole heap of boards............because it will be the most important couple of hours you spend on the entire project.
Mike is dead on.

Yellow stain is the bane of oak users' lives now (and for the last few years). Rushed kilning usually. Annoying and a very good reason to select carefully.

I buy all my kilned joinery oak from the same local supplier and I do not go and choose it (though Mike's advice is spot on) as he knows it will come straight back if he sends me defective stuff. So he never does, but that kind of relationship requires years of doing business.

By the way - you appear to be paying a LOT for your oak if you spent 580 euros on just enough to make a small bench.
Thank you MikeG , that is exactly what I was looking for.
Unfortunately, the wood shop do not allow you to see the the wood before buying (you order and pick up a week later).
I think I will use another wood shop.

PAO is planed all over, it was the term they used on the invoice.
MikeG.":26u1pn7w said:
The yellow stains are fungal, and they shouldn't be there. They are the result of over-cooking the board in a kiln, or, believe it or not, allowing the board to get too hot whilst air drying.
Here is a bit more information on this drying fault from something I wrote a little while back.

Evidence of yellow streaks longitudinally in a board of oak, walnut or chestnut is caused by “metabolization of tannic acid by the fungus Paecilomyces variotii” (Gard, 2010, p6)*. Maintaining sufficient air flow of 0.5 metres per second (~1 MPH) and holding relative humidity in the kiln to below 80- 85 percent are suggestions for preventing the problem. The chances of this fault developing in air dried wood are small.

* Gard WF, et al, (2010) Discolouration of timber in connection with drying, Cost Action E53, Working Group 2 [Online] Available at: <http://www.coste53.net/downloads/Literature/Discolouration%20of%20timber%20in%20connection%20with%20drying/Discolouration_of_timber_in_connection_with_drying.pdf> [Accessed May 10, 2013]

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