Ebonizing oak

Been working on this project for a couple of weeks, trying to get the recipe right. Mix vinegar and steel wool to get iron acetate. The whole shop smells like vinegar. Apply directly to the surface (in this case oak), turns the tannins in the wood to black. This process doesn't seem to soak in like stain. I applied the finish to both sides of the board, then did the carving. Two sided to hang in a window. The result is rather unique. Now for the question. Can I use MinWax Polyurethane as a finish over the ebonizer? Set the board in the sun for a couple of days to get the vinegar dried out? Attachment 77878Attachment 77879

Really a unique finish, never would have thought of the way you combined the materials to achieve the results. Not a chemist but nothing I know of would prohibit you from finishing after the project has totally dried. Please post the final project, really want to see it.
Thx,
Rick H

Jerry, I have used that method on cypress and it aged the wood older after each coat.
I never thought about oak, good idea. I would let dry for a few days and give it a try?

Definitely curious now... what's the recipe. How many parts steel wool to vinegar? And what did you apply it with? Just trying to forego the rookie mistakes if you have it figured out. Impressive sign!

Very unique idea, never would have thought of doing it that way.

My version of the mixture is 6 iron tablets, to a small cup of vinegar. Let the tablets melt for a day or two.
I then just applied it to the wood, letting it dry between coats. I'm not sure about Jerry's method.

I got my recipe off the internet a while back. Quart jar, prox half full of steel wool, covered with vinegar (do not seal-let the gasses escape) - let set for a couple of days or a week. The mixture will bubble and form scum on the top. (Really gross lookin stuff). I added a few small steel nails (not galvanized or coated). To hurry along the solution, I put it on a small cup warmer for a few hours - causes a quicker reaction. My instructions said to wash the steel wool in soap and water to remove any oil - oil inhibits the reaction. So now I have this really icky looking and smelly stuff under my work bench in an unsealed jar. To prepare for use - I screw a cover on tight and shake up the mixture - remove cover and dip brush into said jar. I used a foam brush - and just slopped it on the board. I let mine set for 3-4 minutes, and wiped off. Supposedly this will coat the surface of heavy tannin woods with a black opaque finish. I need to experiment more with this. If the solution is being used up, add more steel wool and vinegar - let set until needed.
I plan on cutting off the ends of this sign and routing over the edges - will try to touch up the worked edges to match the overall finish. Will then try the PolyUrethane. Will post pics when done.
Plain tea (as in tea bags) has tannin in it. Make a cup of really strong tea. My instructions said on softer woods or woods with less tannin - add a strong tea coating to the wood first - let it almost dry - then apply the ebonizer.

I've successfully ebonized several types of wood (to include bamboo, yellowheart, walnut, and pine). A few tips - Degrease the steel wool FULLY (I use brake cleaner), after the steel wool has fully dissolved in the acetic acid (vinegar), FILTER IT WELL - I filtered mine 3 times through clean, new coffee filters. The solids in the solution do not aid the reaction and can create "pin spots" in the final product, especially if you're not going for full on black. Use loose leaf green tea for your tannin source (or buy tannic acid from amazon or a vintner's supply). The result looks significantly better by applying the tannic acid (or tea) to the project to a full wet surface - allow it to mostly dry (until the surface doesn't feel wet to the touch), then flood the surface with the acetic acid/iron oxide solution. Allow it to dry fully (I set mine under a CCFL bulb, about 2" away) for 12 hours minimum. Once it's fully dry, you'll notice a "chalky" tone to it - Apply another coat of the tannic acid to the project and the chalky tone will disappear leaving a deep "blue/black" tone depending on your particular wood choice. I *never* use polyurethane over any of my projects, I only work in hand rubbed oil finishes. Here are some examples:

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