MIMF

Hello!
Have someone make this way of ebonizing wood?
Let the steel in the vinegar for some days and then applying in the wood?

Does it change the resistance of the wood?
I was thinking in use it in a soundboard, but I imagine it would change a lot the wood
Thanks

Vinegar is a very weak acid; it takes more than a few days to get a usable solution for staining.

If by 'resistance' you mean the 'stiffness' of the wood, I'd say no, but that's not based on data. At any rate, the dye probably would not work on a soundboard, since none of the softwoods I know of have a lot of tannin in the wood: it's the reaction of the iron acetate with tannic acid that causes the reaction that produces stable black iron oxide to form. It might be possible to wet the wood with the clear iron acetate solution, and when that's dry, to wipe it down with tannin. As always, the key is to do some experimenting on waste pieces of the stuff you're planning on using.

I agree that what most of what we call vinegar (household) is weak. Acetic acid in industrial strength will peel paint off steel very quickly. The canning vinegar you can buy is usually somewhat stronger than household white vinegar. I've often read about using it for ebonizing higher tannin woods but that's as far as I've gone. The closest I've come is using Tandy's leather dye to even out fretboards etc.

I'm guessing that by resistance, you mean resonance. I wouldn't think it would have much effect on resonance but I don't know for sure. Years ago I did some tests on scrap as I was looking to make an all black guitar. turns our that spruce really doesn't have much in the way of tannins and that is what turns black with this technique. The spruce scraps just ended up looking kind of gross. I have heard of people boosting the tannins in wood by treating it with black tea or similar, letting that soak in and dry, then doing the iron acetate treatment. That just seemed like a bad idea on a mostly finished soundboard. I was already leery about putting too much moisture in with a single iron acetate treatment on such a thin plate so I didn't do any further testing.

Who knows if it would have worked well enough or not. I'm not sure if you would have been able to get enough tannins in to actually make black rather than an ugly gray/brown.

Thanks guys, will think another way...
It's an archtop top I bought that has a very dark wide streak in the middle, like 2" on each side and it needs to have a solid finish, but I don't know anyone here in Brazil near my place that makes finish in acoustics and there is that stuff about 0.02" thickness in acoustics finish and the guys who does electric finish can't do that...

I was thinking in have something like the Gibson Black Beauty Ebony finish, perhaps looking like very old

Hey, this guy from Brazil has 3 videos explaining how he does it and it worked even on pinus. One is talking only and 2 is showing how it's done, I'll put it here, but it's in portuguese, don't know if there is a closed caption to translate to english...

Basically: he add the iron and alcohol in a jar and rest for 3 days, then he makes a hit solution with a high tannin roots or lots of green tea bags on water and apply it 4x on the wood, then apply 2x the iron/alcohol solution and then apply a last tannin juice on it and lets rest at least 12h then apply finish.

The pinus didn't get really perfect, but I think it can get better doing more tannin baths on it, perhaps in-between iron solution applies

https://www.instagram.com/tv/CAY5gqsBeb ... RuejRhMw==

https://www.instagram.com/tv/CAuun0HBWs ... liMzR0NA==

You can use a “tea” from quebracho extract, which is high in tannins and used in tanning.

In the winter 1977 edition of Fine Woodworking magazine there was a letter to the editor regarding the use of this type of solution as part of a "gunstock" finish popular for the maple stocks of old muzzle loading rifles. The author recommended soaking the rusty nails ("very old and very rusty" and "do not use a metal dish") for 2 weeks. Also he says to use organic vinegar ("the stronger the better") that has the "mother" in it (a slime like substance.) I don't know why this would matter but that is what I did.

Over the years I've tried this "gunstock" finish on figured maple three times. The iron/vinegar solution is applied first and turns the maple a gray color. I had a problem with getting consistent gray results with the times I made it. At best it took three or four applications to give a moderate slate gray. (Think photographic 18% gray) I gave up on it because of the inconsistent gray coloring. (I've wondered about using ferrous sulfate, which can be obtained as a dietary supplement, to get consistency.)

Other species will undoubtedly respond differently, but I wouldn't expect spruce or pine to turn black. Another consideration is that your wood has a dark streak already and will require color balancing of the border areas. This is important with a clear finish over the dyed wood, where you'll still see the grain. I've never sprayed a guitar with a colored finish, so can't say how many coats you'd need in that case.

When I did want a black maple I opted for water/alcohol soluble aniline dye. And it took 6 to 8 applications of increasingly stronger solutions to get it NEARLY black. I had to stop because the dye was leaching through the back and becoming visible on the inside.

Other things I found out the hard way:

Make sure to have every last little scratch taken care of before proceeding with the coloring. You do NOT want to sand down to the wood after it's dyed and maybe even the final finish is applied.

Light colored bindings and purflings are a real problem keeping free of the stain. Putting them on after the staining process requires very exact cutting of the channels to minimize any chip-out of the dyed wood or any glue contamination of the dyed surface that requires cleaning up, as it risks going through the dyed surface. Taping over them on the top curves, demands every last little bit of patience. And then some when you find the spot where the dye leached under the tape.

It doesn't sound like you have much extra wood to experiment with and you are going to need to experiment on something similar.

The short answer is that I think you will have to add something to the mix to get it nice and black besides, or instead of, the iron solution.

The iron acetate solution reacts with tannins to form the stable black iron oxide. You need both parts; just as with using epoxy. Oak has lots of tannins and works great; maple doesn't. 'Tea' made from quebracho, hemlock ,or oak bark can be used to add tannins to the wood. Even plain black tea helps, but you need to get both components.