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I believe I saw a few posts of folks who use black walnuts, or at least their husks, to extract a dye which was then used to darken white oak bodies. I remember Haans being able to get striking results (from what I believe was black walnut) and was wondering about the process of producing the dye and then how to apply for such an effect. I'm starting to see a few walnuts dropping already which reminded me of this technique so before I start gathering is anyone willing to share ideas?

IDK about that technique but how dark do you want the oak? A stain made up by boiling fine steel wool in white vinegar will make white oak black. Fuming white oak with strong ammonia will make it dark like a shadow.

Doc, I mixed a lot of blackTempura powder with Stew Mac ebony filler and added some black transtint too. After applying and sanding back, I applied a mix of red and brown mahogany along with dark brown transtint dye to get the color.

Al Carruth uses the technique, maybe he'll drop in and share.

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I make walnut dye as has been stated; by boiling the hulls in water. The dyestuff, called juglone, is present in all parts of the tree more or less, except possibly the sapwood, but the hull have a lot more than the wood, so it's easier to get from then than from shavings.

I have used the iron and vinegar stain as well. You have to allow plenty of time for the iron to react to get a strong solution. The production of a good black color depends on whether there are tannins present.

The same is true of ammonia fuming; it only really works to give a nice brown color when there is a lot of tannin in the wood. White oak fumes up nicely, while red oak turns a sort of greenish grey. I've just been experimenting with that as I'm finishing up an oak guitar now. Alas, it's red oak.... If you have the right sort of oak fuming is the best way to go IMO. For one thing, the color will go all the way through the wood, so there's no danger of sanding it off by accident.

The fuming is pretty easy to do. I did test pieces by putting a small container of household ammonia in a plastic bag with the wood samples I was testing. I kept track of the relative humidity, and found it never got above 70%. It's possible that the partial pressure of the ammonia kept the water vapor content down. At any rate, I put a couple of salvaged silica gel drying packets in with it, and cut the R.H. down to about 50%. That was a small bag, of course, a larger one would require more ammonia and gel packs.

It's especially true in finishing that your mileage may vary. Run some tests to get the feel of what works and how to get results you like.

So is the walnut stain black? Or is it more like a tobacco?

Might have to go to the huge walnut tree in my back yard and get some nuts.

Thanks for all the ideas everyone. I'm thinking if exotic woods get more scarce to use for building white oak may become one of the more popular domestic woods for us to use. Personally, I like the look of it with the darker color so I need to get practicing!

No it's various shades of Brown dependent on concentration. You can also buy it as 'van dyke crystals'.

Just a caveat if you plan to go forward with the walnut husk process. I gave this a shot a couple of years ago, and wore gloves so as not to dye my fingers while removing the husks from the nuts.

Two small holes in the gloves allowed my fingers to get wet with the "juice" from the husks.

Wow, does that dye work well!! A month later, my fingers were still brown.....

The dye is the same color as the heartwood; some shade of brown, depending. It's surprisingly effective. I've used it on rock maple and gotten a color that's not far from actual walnut. You can keep on applying it until you get it as dark as you want. The problem is that it's just skin deep; you have to finish up all of your sanding and so on before you apply the stain. Thus you can't for example, stain the sides and back and then rout the biding channels and install that (unless you're a lot better at it than I am!).

That's one of the advantages of fuming: with an open pored wood such as oak the color will go right through. It seems to penetrate a bit less with Osage orange, but is still better than a surface treatment.

Alan,

Having never tried the fuming process can you give me an idea of how long you keep the wood enclosed in the bag--couple hours, overnight, several days?

Thx!

I wonder if it would be okay to fume a guitar before finish or before the bindings went on. Does anyone know what it does to spruce, WRC, redwood. . . in terms of color? Would there be any negative effects on the glue joints? Perhaps just the humidity alone is enough to steer clear of this idea.?. Thoughts?

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I recently boiled four pots white oak planer shavings into what hopefully will result in a concentrate of oak tannin. I'm hoping that brushing the mixture onto white oak, or other non-tannin woods, followed by a brushing of ammonia, might mimic the fuming process, without the danger of ammonia fumes.
Once I get around to doing some experimenting, I'll post results.

Alex

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I fumed most of my samples for 24 hours. The longer you fume then the darker they get, up to appoint, but most of the change does happen fairly quickly.

As I said, I found I could keep the humidity gauge numbers down by use of silica gel packs. It's possible that those sound hole packs that are supposed to keep a constant R.H. would work well for this.

The last time I fumed one, which was some time back, I just enclosed the whole thing in a big plastic bag for the duration. This was the assembled guitar, ready for finish, but without the bridge on it. I had no problems with the finish or bridge gluing later on.

Alan, would it be fair to say that the fuming didn't affect the coloration of the rest of your guitar much/any? Since the top likely had little if any tannins and possibly the same for the bindings those woods were essentially the same color as prior to the process?

Right. The spruce tops hardly change at all, nor do woods like maple. Cherry seems to be affected some, but not much. If you have any hesitation about a wood you want to use, experiment! It's easy to make up small samples from cut offs, and fume them in a plastic bag for a day or so. Some woods can turn greenish or grey, and you might not be happy with that. I'm far from the world's living authority on this, or much of anything else, for that matter: don't take my word!

If you make a tea with quebracho bark powder, and paint it on the wood you plan on fuming, it will increase the tannins in the wood considerably. The increased tannins allow the color change to be darker and full penetration. You can get the powder at any good taxidermy supply outlet, I got it from Van Dykes online a few years ago. The bark tea is easy to prepare and can be made up right before using it. I just put a heaping tablespoon of bark powder in a pint of hot tap water and stir it up well. I used it to add tannins to some cherry wood to turn it deep black with the vinegaroon (vinegar & steel wool) solution. Alex, if I can remember , I will bring you some powder to Exotic Woods Guitar days in Sept.

Bob

Thanks Bob! I read about the quebracho bark powder a few years back, and totally forgot!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker