Google will provide you with a lot of information on this process, but briefly, the common practice for ebonizing involves creating iron acetate by combining strong white vinegar and steel wool and allowing them to stew for a while. When it's applied to wood, it reacts with the tannins in the wood and turns it black. The greater the tannins, the blacker the result. Oak is highly tannic, so it's a good candidate.
I tested my brew on some oak off-cuts that had been sanded to 180. This is the result of two applications followed by some Odie's Oil (which is easy and quick to apply, giving the same oil/wax look as Rubio).
To boost the wood's tannin levels, you can apply a tannin "tea" to the wood first. I made some using a bag of wine-making tannin powder - made from some kind of nut I believe. Since I needed to water pop the oak frame anyway, I used the tannin tea solution to wet the wood. Win-win.
After that dried, I lightly sanded back with 180 then repeated the process one more time.
The results were pretty dramatic when I applied the iron acetate. I didn't get any pics during the process because I had gloved hands, but it's really amazing to watch the wood turn black before your eyes. Here is the final result.
I need to go back and work some solution into some of the borer holes that were missed. After a very light sanding, the frame will be ready for finish.
I like the "magic" of that process, looking great! Oak is always a pain to get any dark finish to also darken in the pores, but worse come to worse, with the black one can always follow up with a fine point sharpie.
Cool thing is everything goes jet black when a top coat is applied, kind of like when fuming and then turning the green/grey into a nice brown.
Splinter - I did find that the pores seemed untouched on my sample blocks, but that after applying Odie's they appeared mostly black. Maybe a change in reflectivity with the finish? Or maybe just some of the black rubbing into the crevices when working-in the Odies?
With the tea applied to the frame first, the surface ended up a fairly uniform black, even in the pores.
Usually on the stuff I dye dark, I'll apply Minwax "special dark" paste wax and work it into the pores to eliminate the "white". I'd suspect your Odies is doing the same.
Fun fact about your "tea" You can also use a standard Lipton tea bag (a.k.a Liptorn). Just dip it in a cup with enough hot water to saturate the bag and start applying like you would with a towel dipped into stain.
Helps if you have a box of the buggers from the 80's stashed in the back of a cabinet. 😝
If you want a black with some depth into the wood, the tannin booster is a great technique!
Thanks gents. I was anxious to see the frame with some finish on it, so I mixed-up a little Rubio Pure and went to work. I'm happy with how it turned out.
That turned out very well. The process also sounds a lot more fun than just wiping on some black stain.
It looks like you got a bit more sheen out of the Rubio than I did. I’ve used it just once (on our kitchen table), and the resulting surface was very dull and sort of lifeless. I ended up applying Rubio Maintenance Oil to give it some life. Your finish looks good right out the gate.
Ron - thanks. It is kind of a fun science experiment watching the color change. Regarding the Rubio sheen - I do think that there is a wood species component. Or perhaps a dependency on hardness. The frame had been sanded to 180 prior to applying Rubio, and with one coat it does have a nice sheen. The cherry stool that I built recently was sanded to 220 and required two coats of Rubio to achieve the same sheen. I'll probably apply a 2nd coat to the cabinet frame just for good measure. I'll wait a day or two, scuff the surface, and apply.
Man - that is looking great! That black is going to be an excellent contrast with the cabinet. I recently finished a project where I attempted fuming oak. Interesting process and I was pleased with the result.
Ross, I suspect you’re right about the type of wood making a difference. I used Rubio on basswood, which is the softest wood I’ve ever seen short of balsa.
Rust-and-vinegar stained oak with oil on top. My favorite combination! I like to wet-sand the stain in with 220 grit paper. That presses the stain (and some black sanding dust) into the pores and makes the problem of light colored pores less of a problem
"The good chair is a task one is never completely done with" Hans Wegner
Kaerlighedsbamsen commented about 16 hours ago new Rust-and-vinegar stained oak with oil on top. My favorite combination! I like to wet-sand the stain in with 220 grit paper. That presses the stain (and some black sanding dust) into the pores and makes the problem of light colored pores less of a problem
Ty - I hadn't thought about wet sanding while applying the iron acetate. I'll store that tidbit for future projects.
