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Oxalic to clean wood metal stains in Oak

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Oxalic to clean wood metal stains in Oak

#1

Oxalic to clean wood metal stains in Oak

Keith Newton

I'm trying to assort some of my wide QS White Oak lumber to cut up for drawer fronts / end parts / front elevation. Most of what I need will be 12 1/2" wide, and the lumber is wide enough except there were some nails driven into the tree about 10" in from the outside. The black staining ran up and down about a foot each way, and out about 3" around the nails, so this warned me to find it with my metal detector and cut them out before hitting it with the band-mill blade.

Now that I'm using this wood, I'm needing to include some of that stained wood for some of the larger pieces. What I'm wondering is will the oxalic acid have any penetration, or should I wait until I'm down to the final sanding? I have surfaced and planed it down to the final thickness, but will have 2-3 more grit changes before finishing. I'm thinking I might start now, then do it again closer to finishing.

Oh, One more thing I've been thinking about sharing with those of you that harvest your own wood. The common definition for medullary rays states that they radiate out from the pith. However they may not be a straight line for infinity. They will bend around buttresses and flutes. Another way of thinking about it is that the rays will always be perpendicular to the outer surface. Where this matters, is when your are going for the best yield on a really large Oak, they will often have one or more flat sides. If that flat side has been flat since the tree was 2' smaller, there should be a good stack of 1' wide QS boards that don't need to be tipped up and cut into wedges first to keep the big flakes. So when your trying to break down a large tree with the chainsaw try to plan ahead so that billet ends up going onto the mill so the blade is perpendicular to that side.

Re: Oxalic to clean wood metal stains in Oak

#2

Ellis Walentine

Experiment

Ellis Walentine

If you soak the stains with the oxalic acid solution earlier, the worst that can happen is that you'll have to do it again after you've sanded or planed off any additional material. My hunch is that you might as well wait until the end. You'll have to let it dry out and knock off the raised grain, but you'll be attacking the stain effectively.

Ellis

Re: Oxalic to clean wood metal stains in Oak

#3

Re: Experiment

Keith Newton

Thanks Ellis. I did brush some on yesterday for a test. I laid it on pretty heavy, but mixed according to the directions on the container, which was a rounded table spoon per quart. It did a pretty good job on all but the darkest places closer to where the nails were. However it did leave a stain along the wetted edge that by the time I sanded it off, I was starting to see a hint of gray coming through from below.

After having done that, I found a discussion on another woodworking site where they called for twice the concentration that I had used. I have plenty of time before I get to finishing for it to dry out, so not worried there. And it will be stained medium brown so I probably don't need to worry too much about the faint gray if it shows up after sanding the water mark edge.

Next question maybe Bill can answer, is do I need to mix a new fresh batch each time I need to use it, or will my pint jar ( one cup liquid, 1 cup air over) with lid keep it from loosing strength? I don't suppose I really need an answer, because I'm sure I have a lifetime supply, and would rather not have a glass jar out in the shop to get knocked over and broken.

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