Removing Discolouration

[Andrew Armstrong]

Hi, I'm re-finishing the top of this guitar and where the old pick guard has come off the top is discoloured, or rather it hasn't coloured while the rest of the guitar top has got darker. The pick guard is a sort of tiger stripe "tortoise shell" and you can see this in the discolouration.

Has anyone got any ideas about how I can even out colour? Some additional info:

The owner would like to stay with a light plain spruce top
I'm converting to Left Handed so the pick guard will be going back on on the opposite side
I've sanded back to bare wood and I'm not too keen on sanding too much further in case I thin the top too much.
I've tried some oxalic acid (bleach) solution but that doesn't seem to make any difference.

Would appreciate any advice.

Andrew

[Clay Schaeffer]

You could try potassium permanganate to "age" the wood in the pickguard area, and then give the whole top a wipe down with it to try to even things out. Eventually the area will darken on it's own, but it may take a few years. I would avoid sanding as much as possible.
Another possibility might be to do a double pick guard. If the owner doesn't mind a refinished top he might not object to having a pick guard above and below the strings.

[Doug Shaker]

The owner might not agree, but I think the history of an instrument makes it more interesting, more valuable, deeper, with more wa, spirit, or chi. If I could, I'd just live with the color difference and make it into a good story.

But I'm not the owner.

[Chuck Tweedy]

Or just keep sanding.

[Warren May]

Or you could put 2 pickguards on it. I like the shape of the old one and one just like it on the "lefty" side would look "cowboy cool", I think. (Edit: Guild makes a Ritchie Havens model that has a pickguard shape a lot like yours...Ritchie tore up guitars pretty badly)

[Chuck Tweedy]

By the way, I was joking. I realize after reading again it needed a qualifier.
You don't want to sand too much off that top - as you already said.

Eventually exposure will even it out, so I'm of the mind to let the customer explain that it is a lefty conversion until the evidence fades.

[Trevor Gore]

When all else fails....

Give it a sun tan.

Exposure to UV light will even things up (friend with a tanning bed? UV cure lights...?) You could try masking things off except for the old pick guard area, so that area catches up a little and then give the whole top a blast to even things up a bit. Don't sand after the UV treatment or you'll likely get more blotchy. Don't expect it to totally disappear either, but it should get less obvious.

[Andrew Armstrong]

Great, thanks for those comments. I may test a few things but I'm concerned about making it worse. The sun lamp idea is interesting - I don't have one or know anyone but I'll enquire. And I do have some potassium permanganate and I tried a little in the bridge area as a test but maybe I didn't get the strength right - has anyone got any rules of thumb for mixing the stuff? . Also trying to paint it between the stripes of the "tiger" is a challenge. Any way I'll keep you posted and if anyone else has any bright ideas, keep them coming.

[Bob Gramann]

One of my internal mottoes when I'm dealing with finish is "You can always make it worse."

[Michael Lewis]

As someone who has done a bunch of this sort of work I advise you to lower your customer's expectations to live with what he has. The least obvious conversion would be to have mirrored guards. Anything you do to the wood to try to make it more even in appearance is likely to make it more odd and noticeable. I suggest putting some color in the finish to at least make it look a bit older. It may help cover some of the areas you have sanded the 'tan' off of just behind the bridge and down in the lower bout.

At this point I would measure the thickness of the top, and if there is enough wood I would sand to get a more even coloration. If the top is around .100" (2.5mm) I would not sand any more, and go with the 'aging toner' in the finish. Some of it will show no matter what you do. This sort of situation is where sunbursts come in handy.