What causes this?

[Jak3]

I have been working on a new furniture project recently, the first project at home that involves me milling my own wood, whereas the previous project used wood already dressed. I noticed something peculiar in the white oak which will become the top. I have seen this before in both white and red oak, random black streaks latent throughout the piece. I was wondering what causes this? I have no idea but to guess maybe fungus or iron embedded in the tree stained it or something? I kinda like it but wonder how it will look with finish, I will be using Arm R Seal satin when the time comes.

Here is what it will be:

The top with the black streak:

Progress:

Joinery thanks to this amazing tool:

 

[LeftyTom]

Scott Smith may be able to answer this for you.

 

[Jeff]

It looks like a stain from iron and the tannins in white oak which forms iron tannate (black).

 

[Mike Davis]

Sometimes the stain can be removed with lemon juice and a little salt on a clean rag.


If that doesn't work then oxalic acid is the only solution.

Do some research and be sure you are OK with handling chemicals before jumping into the stronger acid approach.

 

[zapdafish]

from what I've seen black stains from iron can travel surprisingly far from the nail.

 

[Bernhard]

Probably contact with iron as others have noted. May want to try a bit of oxalic acid to remove. Usually does not happen with dried oak, was the lumber dried to below 8-9% MC?

Cheers,
Bernhard

 

[Jak3]

Probably contact with iron as others have noted. May want to try a bit of oxalic acid to remove. Usually does not happen with dried oak, was the lumber dried to below 8-9% MC?

Cheers,
Bernhard

No, it was air dried outside in a barn for at least 2 years.

 

[scsmith42]

It looks like a stain from iron and the tannins in white oak which forms iron tannate (black).

What Jeff said.

White oak is very susceptical to metal stain when it is green. Typically it’s caused by someone putting a nail into the tree (think bird house, tree stand, wire fencing nailed directly to a tree, etc. This is one of the reason why commercial sawmills will not purchase “yard trees”

The stain can also occur when freshly milled oak is exposed to metal - such as the bottom layer of a stickered stack of lumber being in contact with forklift forks. However, typically the stain that occurs on freshly sawn lumber will only be on the surface; whereas the stain from metal in the tree will travel usually an inch or so horizontally in the tree and up to several feet vertically.

Scott

 

[Jak3]

What Jeff said.

White oak is very susceptical to metal stain when it is green. Typically it’s caused by someone putting a nail into the tree (think bird house, tree stand, wire fencing nailed directly to a tree, etc. This is one of the reason why commercial sawmills will not purchase “yard trees”

The stain can also occur when freshly milled oak is exposed to metal - such as the bottom layer of a stickered stack of lumber being in contact with forklift forks. However, typically the stain that occurs on freshly sawn lumber will only be on the surface; whereas the stain from metal in the tree will travel usually an inch or so horizontally in the tree and up to several feet vertically.

Scott

Very interesting, thank you for the information!