My process for vinegar and iron is to drop a pad of #0000 steel wool in about a quart and a half of vinegar. Let it sit until the pad is dissolved, perhaps a week. This stuff will ebonize most wood quite well.
Incidentally, avoid breathing nitric acid, and never breathe the fumes from burning nitric acid; use the stuff outside. Actually, there's enough good products on the market today (art supply stores are useful) that one need not use strong acids.
I
f you use acid, make sure to neutralize the acid bath with a strong base, such as lime. Ever see a contemp that turned a funky green hue after a few treks to the mountains? That's what sunlight does to un-neutralized acids in wood. I'm no chemist, but rather the only English major in college to get permanently banned from the chem lab. Seems I was in the process of brewing up a batch of nitrogen triiodide for amusement when the dean made an unexpected visit. JWH
