Official Luthiers Forum!

It's been a long time since I have posted, but retiring at the end of the month and starting up my building in anticipation of having more time to make guitars and play. I am very pleased with this first experiment with fuming a quartersawn white oak body with ammonia. I am not aware if this technique, while commonly used to darken furniture, has ever been used to darken a guitar. I used over-the-counter strength ammonia and sealed the body with a cup of ammonia in a plastic container about twice the volume of the body. I let the process go for about 6 hours. The temperature was about 70 degrees F. In these pictures there is a single wash coat of shellac on the body. What do you think?

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

I like it! And, I have a board of quartered white oak too.

_________________
Steve Smith
"Music is what feelings sound like"

I like it! I’ve got an oak build coming up, I may give that a go…

Steve--

It looks great! You should be pleased. I do have a question, though. Have you tried getting to the same shade by using multiple coats of Garnet shellac? I'm working on a QS white oak guitar right now, and while I didn't go as dark as your fumed oak, the Garnet did give me some color. Interesting wood to work with. Pore filling was a bit of a challenge. I had to apply several more coats of epoxy than I normally do. But it turned out great, and I am excited to get the finishing over with so I can string it up.

Thanks for your comments Don. I’d like to see yours! The thing that surprised me and I like so much about mine is the difference in the reaction between the sapwood and the heartwood. The sapwood did not darken at all from the ammonia. It would not be quite the same contrast if I only used some kind of finish I would guess. Definitely going to get some garnet though and try it. Cheers.

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Looks gorgeous to me!

_________________
"Act your age, not your shoe size" - Prince

Wow it definitely made that oak more interesting. Very cool.

I fumed the body for a black locust guitar I recently finished.

Black locust is rather plain / bland otherwise. Fuming brings out the character.
I read of others fuming guitars when I was researching fuming, so you and I are by no means the first.
Good looking guitar. I’ve got a red oak dread I’m very fond of.

I'd love to hear more about the fuming-with-ammonia technique. Like what to do when and how, and when in the build process?

Thanks!

_________________
Peter Havriluk

Looks good, really makes the oak-flake figure pop!

We used to use industrial strength ammonia (Effin nasty!) in a poly bag tent with the addition of UV lights. The results ended up quite a bit darker. At one point we started brushing on household strength ammonia, no tent, plus UV with similar results.

M

Steve--

Here is a photo of the one I am working on right now:



As I mentioned, the Garnet has not darkened mine as much as the fuming has darkened yours, but I bet if I put on a lot more coats, it would go darker. But there is a risk of unevenness if I put too much of this on. I think both look great as is!

In my case - after the box was closed Fuming will permeate through the wood, so it doesn’t have to be finish sanded.

I suspended the body from a frame so the ammonia could circulate all around it. It was a bolt on neck so it hung from a string through one of the bolt holes.

The ammonia needs to be contained around the body. I used a large clear plastic bag. Placed an open container with approx a half pint of household cleaning ammonia ( the lemon scented kind) in the bag with the frame and guitar body, then closed the whole thing up. The clear bag let me monitor what the guitar looked like. I hung it overnight, perhaps a little longer, for the color change seen.

I tested with cutoffs suspended in jars with ammonia to check the color. I also used the cutoffs to verify the color didn’t sand away. I also tested that parts would still glue up well after fuming.

I let both my test pieces and the guitar out gas for at least a day before doing any sanding or glue tests. I recall ammonia being used to bend wood, so I wanted to make sure everything had stabilized before I proceeded with any other work.

Hope this helps.

Appreciate the update on guitars and fuming! I love black locust so this is good to know!

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Peter, I did the fuming after finish sanding the body and before pore filling. The body is ready for finishing after the fuming process. The ammonia was in an open bowl, about a cup of fluid, in the container. The color depends on time, temperature, concentration of ammonia, and the amount of tannin in the oak. For this reason, you probably should not mix wood from different billets. I use a transparent plastic container so I can monitor the color change. The container should be sealed to concentrate the fumes and prevent leakage. I have read that heating the ammonia accelerates the process, but with a small container (relative to a furniture-sized enclosure) it would be easy to overshoot your desired result.

Ammonia is a very dangerous gas to breathe. I did this outside where I could crack open the container without a mask. Using strong ammonia would require a serious mask rig with the proper filter(s).

You could use offcuts and experiment, but I have done this with furniture a few times, so pretty confident about the outcome being satisfactory, so I just winged it and monitored every half hour or so.

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Cool!! Lovely bit of Oak there, Don! I see you love to let the wood to tell the story.

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Looks really nice! I am working on one as well and plan to fume once the box is closed so am glad to hear of your process and success. What top did you use, and did you notice any coloration change to it from the ammonia? With mine I'm using red spruce with an oak rosette--fingers crossed for it to have a nice contrast.

Thanks for sharing,
Doc

It looks great. I love white oak for guitars.

Doc, the top is Sitka and there was no change in it's color from fuming as far as I can tell (I did take before/after pics). Make sure to share your result. Cheers!

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Very very cool, and I'm impressed that you can do it on a closed box without glue issues. I LOVE quartersawn oak for guitar backs and sides, except the color is so blonde. I'm always worried about dyes and stains blotching the top and such.

I'll definitely be trying this out.

Thanks for the additional comments. As for not mixing wood from unrelated billets, that makes sense but for purchased b/s sets, unless the vendor (cutter?) states that the wood is all from the same billet, and charges for it, I'm guessing that the sides aren't related to the back.

_________________
Peter Havriluk

Steve, that guitar looks great! Thanks for posting, I've been looking for guitar specific information on this process and there's a ton of good info in this thread.

I'm about to start a 13 fret Nick Lucas with Sycamore back, sides, and neck. I stumbled across this European veneer supplier in my search for more information on the process and I knew I needed to try it out on this guitar...the fumed Sycamore looks almost like photo negative Snakewood! Should be very eye catching on a guitar. Reminded me a lot of Haans Brentrup's moonburst mandolin he posted here years ago.

https://www.mehling-wiesmann.de/en/produkte/plane/

Oh heck - I can see some testing on sycamore happening ASAP. Did not know it would work on that species.

On that website, I didn’t see sycamore. Is “plane tree” a sycamore? Edit - a quick google says yes. Nice!

I love the results. Osage Orange responds very well to fuming as well.

_________________
http://www.Harvestmoonguitars.com

Excellent to hear.

Yep, even with stuff I resaw. I've resawed all my own oak for back and sides, and I generally try to find pieces that look about right, though I don't insist they come out of the same billet. It's a lot easier to find full width quartersawn with dead straight grain in 5" boards than in 10" boards. Since I haven't fooled with stains or dyes, I don't even insist on keeping white vs red "pure." I had just looked for the grain to be about right, but that would probably matter for fuming. It's just so darned blonde without anything.

Good to know on the Osage Orange. That stuff looks like nuclear snot straight off the saw... Day glow chartreuse... Like cherry, it darkens into a really pretty brown after a couple weeks in the sun. I've got an Osage Orange back and sides with purpleheart binding sitting on the bench. Luckily, it's crazy muted from sun/finish to brown/dark brown or I wouldn't like it.