!@#$ Stain on Spruce top! Help!

[PhilQ]

I am in need (and hoping for) a life saving tip here.

I am working on a build, and I found an amazing Adirondack top for a client. Glued up the top, finished the rosette. I've put a lot of work into this one.

One of the plates had a weird greenish stain near the center seam. Almost looks like highlighter ink. Maybe a couple inches long and half an inch wide. I just flipped it to face inside the guitar, thinking it'd be fine once I'd thickness and sand.

Well, it turns out that now that I'm sanding the top, I can actually see the stain on the outside too. Not sure whether I'm seeing it through the spruce or if it's stained all the way through. I have no idea what to do about this, other than to start from scratch, which considering the amount of work I've put into the rosette and everything else, is pretty discouraging.

Any advice from the more experienced luthiers?

Thank you in advance!

[Scott R]

Wood Bleach?

[PhilQ]

No idea what that is! I'll look it up.

[Ned Milburn]

Some wood gets this discoloration. I believe that sometimes it is a natural occurrence while the tree is alive, and other times it happens after cutting and storing.

If this stain exists and bothers you, then I guess the top isn't as amazing as you first believed.

Can you separate and rejoin with what is presently outside edges??

You could try a bit of regular bleach (watered down of course) on a small spot that will be the inside of the guitar, and based upon results, either bleach the whole thing or just live with it.

Ultimately, wood is cheaper than your reputation. If you are concerned, chances are other people will be, too. The option always exists to scrap it and get another piece.

Where did you get your wood? What "grade" was it? Is the grain 90 degrees (ie: perfectly quartered)? How is the grain run-out?? My experience with bulk wood suppliers is that often "master" grade wood is my "F" grade wood - F for firewood. Specifically, grain run-out is an issue. In my standards, wood that has grain run out from one side to the other within 4.5cm does not at all classify as "master" grade. In fact, I wouldn't even use this wood for a student guitar. That's just me, though. Other people may be different.

[PhilQ]

Originally Posted by Ned Milburn

Some wood gets this discoloration. I believe that sometimes it is a natural occurrence while the tree is alive, and other times it happens after cutting and storing.

If this stain exists and bothers you, then I guess the top isn't as amazing as you first believed.

Can you separate and rejoin with what is presently outside edges??

You could try a bit of regular bleach (watered down of course) on a small spot that will be the inside of the guitar, and based upon results, either bleach the whole thing or just live with it.

Ultimately, wood is cheaper than your reputation. If you are concerned, chances are other people will be, too. The option always exists to scrap it and get another piece.

Where did you get your wood? What "grade" was it? Is the grain 90 degrees (ie: perfectly quartered)? How is the grain run-out?? My experience with bulk wood suppliers is that often "master" grade wood is my "F" grade wood - F for firewood. Specifically, grain run-out is an issue. In my standards, wood that has grain run out from one side to the other within 4.5cm does not at all classify as "master" grade. In fact, I wouldn't even use this wood for a student guitar. That's just me, though. Other people may be different.

Hi Ned. You're asking good questions, some of which I don't have the exact answer to. I can't cut and rejoin. Not big enough.

I bought the set from a guy I met who travels the world and collects wood samples. He had a some nice ziricote and some Adirondack sets. I bought a few from him. He didn't "grade" them. I just took the ones that looked the nicest to me, though I am far from an expert. It looks pretty perfectly quartered to me. As far as the runout, I understand what it is, but I'm still not exactly sure how to be able to tell just from looking at it. In any case, the point wasn't so much how amazingly perfect the set is, but the fact that I put a lot of work into it already and was hoping for a solution other than having to start over. Here's a picture of the stain. I wet it with alcohol so it looks a bit worse on the picture.

[Ned Milburn]

Yes, that looks pretty disconcerting.

You can check for grain run-out by splitting a corner of the wood - just a half inch or so - to see the direction of the split. If the split runs parallel to the top or close to it, you are looking good. If it is a noticeable angle, you know you've got some grain run out.

It must be remembered, however, that sometimes one edge of the wood will be a greater victim of grain run-out than the other edge. Hence, you should try to join the edges with the least amount of grain run-out to keep this portion of the halves in the center of the guitar, with the grain run-out towards the guitar edges.

Is your wood large enough to flip and use the discoloured section underneath the finger-board extension?? (Possibly not, since it looks like you've already cut to the shape of the top already.)

PS - I understand not wanting to redo something already done. I, in fact, have a perfectly fine, nearly finished, classical/flamenco neck in my shop that I thinned about .5mm thinner than I wanted, so it has now become a "demonstrator". Also, I've got a few tops hanging on my walls joined and thinned, but that I am not using. Two because of bad grain run-out, and one because I thinned it a bit too much when my thickness sander was new to me. Easy come, easy go. Tuition fees!! ;-)

[PhilQ]

Thanks for the great info, Ned. Yeah, it's pretty much parallel.

I wish I could flip it, but I already finished a pretty elaborate (for me) rosette on it.

I really didn't think this was going to be an issue. It didn't look too obvious before sanding, and wasn't noticeable from the outside at all. Now it is.

I'll try the bleach suggestion. But it sounds like it's probably a lost cause.

I guess I can always keep it and reuse it for a sunburst top down the line...

Thanks

Phil

[repete]

Oxalic acid is "wood bleach." DO NOT use regular bleach (sodium hypochlorite)

OA is very commonly used for evening out color in wood.

Try a small amount on the stain and see if it improves.

-r

[fazool]

Sounds like a contaminant stain - something like a copper or corrosion stain that got inside the tree. Perhaps a hundred years ago, some forester drove a nail in the tree and it, rusted away. Who know. Maybe a stray blacksmith's spark or a wild cowboy shot.

But I am (purely) guessing it got there in the tree's life, not after it was cut.

[PhilQ]

could be... i guess ill try the oxalic acid if I can find some locally

[Lespaul123]

let's see this rosette! You mentioned it a few times in your posts and got my curiosity peaked.

[redir]

That's too bad but it happens, not just that but a whole lot of it happens, happens, when you build guitars. IF it had more of that discoloration then it would probably be better, at least it would have a story. Who knows maybe that was one of Billy the Kid's bullets lodged in the tree

[Jim.S]

Ha! "Wild cowboy shot" and "Billy the Kids bullets". If I could not remove it with oxalic acid I would run with the imagination of these two fellas and call it provenance.

[printer2]

Have a top where a pitch pocket appeared. Using it for myself.

[Aubade Acoustics]

Phil, we have local paint stores that sell wood bleach to lighten wood. Might check your area. The problem will be that you will probably not get just the stain out without lightening the wood around it. You might have to bleach the whole top and even then it will be tough if the rosette is in. If it were my top I would cut out the rosette and start over with a new top. It's those kind of things that can really test your resolve. Good luck with it. Hope it works out for you