I would like to try the ebonizing “recipe” described at the very back of FWW issue 196 (the Norm issue) titled How They Did It. The author describes a technique used by Kevin Rodel to ebonize cypress and cherry. The first step involves using a chemical solution composed of “equal parts water, vinegar and steel wool.” I mixed up the concoction over two weeks ago and the steel wool has still not dissolved and the liquid is still clear. Any thoughts on what could be I doing wrong?
The article also recommends pre-treating the wood with tannic acid. I was going to do this on oak so I am guessing the pre-treatment is unnecessary. Have others tried this on oak? (Yes, I will do samples first once I get the steel wool to dissolve.)
BTW, the second step is a coat of water based dye.
Thanks for any suggestions.
Chris
Replies
What kind of vinegar did you use? I've used vinegar only (no water) and steel wool. Also, it might help to wash the steel wool in soapy water first, to remove any oil.
The solution is very effective at ebonizing oak; there is no need for additional tannic acid. Somewhere, I saw an online video in which the technique was demonstrated (with white oak, I think). Maybe at the Wood Whisperer site?
-Steve
Congratulations, you proved that hydrochloric acid is a faster and better acid to create an iron solution, you formed iron chloride and iron acetate into the solution. Any acid will form a solution of iron, the stronger the acid, the faster and more concentrated solution (if you use sulfuric acid then you get iron sulfate). Any vinegar will form iron acetate, White, brown or black (Balsamic) will do it, what makes it have more dissolved iron "salt" is the larger acetic acid concentration, not the type of vinegar, but vinegar takes a longer time to form it (a weak acid). When the common salt (sodium chloride) is dissolved in water and chloride ions are formed, they will take the hydrogen ions from the acetic acid forming hydrochloric acid (a strong acid).
One of the reasons why I NEVER use steel wool to make iron acetate is because it has oil (a contaminant) and I'm not willing to wash it out when there is plenty of iron around to add to the vinegar. If there is iron oxide already formed (rusted iron) the formation of iron acetate in the solution is faster. If you wait long enough, that oily steel wool will form the iron acetate you need, with oil on the surface as a contaminant.
If you want to darken wood with low content of tannic acid with iron acetate, prepare a strong tea solution and brush/spray it on the wood, but the results are not good.
Depending as it does on the tannins in the wood, this kind of chemical ebonizing seems to me more of historical interest since the effects can vary from board to board--which is occasionally a problem when wood comes from different trees. I'd go to analine dye from the beginning. Some give bluish casts that might not be desirable, but there are lots of "black" out there. A good source for dye, with a wide range of colors including at least four different blacks amoung the water based offerings is http://www.wdlockwood.com . Other sources for the Lockwood dye include http://www.toolsforworkingwood.com and, sold under the Moser house brand, Woodworkers Supply at http://www.woodworker.com
The scientific responses to your thread provide sufficient material for a quick result.
Solomon Island carvers, with a lot more time and patience than I have,
bury their unshaped blanks in mangrove mud for a couple of months, and I can assure you that their finished pieces will pass for ebony under any examination.
Much of their work is decorated with pearlshell inlay, and the contrast
adds a dramatic touch.
Lapun.
Below is a link to the video I produced for FWW.com about ebonizing white oak. It requires membership to view.
The recipe I used was vinegar and steel wool. I didn't wash the oils off the steel wool prior to adding it to the mix (I didn't realize I needed to) and the solution still worked after just a few days, as you'll see.
http://www.taunton.com/finewoodworking/subscription/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=24643
- Matt
Thanks everyone for the tips and alternative techniques. I concluded a number of things:
1) I used apple cider vinegar which apparently takes longer than plain white vinegar.
2) I was looking for all the steel wool to dissolve but apparently it does not.
3) I was looking for the solution to change color but in Matt's video it did not.
4) Next time I will probably not add water to minimize the grain raising.
5) I will also try washing the steel wool first to remove any oils and jump start the rusting process.Thanks again for all the help.
Chris
The solution does change color a bit, but not very much. What is very noticeable, however, is the change in odor. The dissolved iron gives the solution a very distinct smell.
It's been a while since I played with this, and I don't remember exactly what I did, so out of curiosity I put some Liberon 0000 steel wool (oil free) in a jar of white vinegar before I went to bed last night. About half an hour ago, I took some of the solution and painted a little of it onto a piece of red oak. This was the result after a few minutes--as you can see, it takes very little iron to have a significant effect:
View Image
-Steve
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