Ebonizing Wood
I wanted to ebonize a few small parts of the workbench, namely the vise chop garters and the through tenon tusks. Ebonizing is a fancy term for making wood black, or nearly so, traditionally as an alternative to using actual ebony (Diospyros ebenum, Diospyros dendro, etc.) which is limited in supply and therefore expensive. Even ebony wood can vary from nearly solid black to shades of grey to “striped” where parts of the wood are dark and parts are light, so techniques have been developed to even out the tone. The main difference between ebonizing and just painting the wood black is that paint sits on the surface, obscuring the grain.
Ebonizing With Iron Oxide
2010.06.05
One common way of ebonizing is to take advantage of a chemical reaction between iron oxide (rust) and tannins in the wood. Some woods have more tannins than others (oak works well), so the effectiveness can vary. An article by chairmaker Brian Boggs in the June 2009 issue of Popular Woodworking (#176) detailed his method of ebonizing, using quebracho bark powder to increase the tannin content before applying the iron oxide. Chairs are often constructed from a combination of different woods; the examples of his work in the article have a deep, even black color.
So I tried his method on some test pieces of poplar and red oak. I mixed up a “tea” of the quebracho bark powder and let that soak in first, then put on the iron oxide solution (steel wool dissolved in vinegar).
Well, I was nonplussed with the results.
I tried two different brands of vinegar with the steel wool. One I let sit for a couple months, the other for a couple weeks. I tried repeated applications of the bark tea and iron oxide. No matter what, I could not get anything more than a charcoal grey, and usually an uneven tone at that. Obviously his method works, but I was not able to recreate the results in my experiments.
Ebonizing With India Ink
2010.07.03
So I abandoned that approach and tried another: india ink. India ink is basically carbon soot dissolved in water or shellac. This approach is more like painting, there is no chemical reaction in the wood, but the viscosity is so high it soaks into the wood and stains it black. I used Speedball brand Super Black India Ink.
2010.07.10
Tung Oil Finish