Black Spots in Maple

[Chris Padilla]

Any tricks to lightening up dark spots in maple? I tried some household bleach (Chlorox) on a piece of scrap, left it out in the sun, touched up the dark spot several time over the day and it didn't seem to do much.

Do I need a stronger bleach? I'd rather try to bleach it out versus cutting it out and inlaying some lighter maple but that is a possibility I suppose.

I'm putting together one cabinet of an entertainment center. This piece is a drawer front.

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[sheldon pettit]

Hi Chris,

Get some PP [potassium permanganate at a water softening business [think culligan etc.] and go online and order some photographers hypo solution, [sodium hyposulfate]or if you have a local photography shop, there also. Mix 1 oz of PP in 16 oz. of distilled water, mix the hypo in the same way only at 8 oz. of hypo to a pint.

Apply the PP to the black mineral area[s] , and let sit for a minute or so, bot don't let dry, use a small artist nylon brush to do this with, no. 1-2, keep the pp inbounds of the marks also. then while the pp is still damp, apply the hypo directly over it in the same way and care, ok? within a minute it should turn white, when it does, then dab off the excess with dry cotton material and when surface dry, use a wet rag of water to wash it off. From what i see, it may take more than one app, if it does not remove it get back - there are other ways to correct it ok. i use this one most often because it lightens the wood up enough that i can then add color to it if needed. ok? [easier to darken wood than to lighten. ]

Sorry Chris, forgot to mention you can reduce those formulas as needed, for example 1/4 oz. of PP to 4 oz. distiled water/ 2 oz. of SH to 4 oz. wtr. or even less ok? also if it does not do the trick, it is likely not a mineral streak but something else. Somethings it works great on - others not.

[Chris Padilla]

So I found the PP on eBay pretty cheap and easy: $2 for an ounce and $2 shipping: DONE.

The hypo solution was bit more challenging as I'm finding alternate names from what you suggested: sodium thiosulfate seems to work better as I found equally cheap resources of this on eBay.

Cool...thanks! I'll report back once I have everything.

[sheldon pettit]

So I found the PP on eBay pretty cheap and easy: $2 for an ounce and $2 shipping: DONE.

The hypo solution is bit more challenging as I'm finding alternate name from what you suggested: sodium thiosulfate seems to work better as I found equally cheap resources of this on eBay.

Cool...thanks! I'll report back once I have everything.

God deal, thiosulfate will work , no problem.

[Chris Padilla]

Okay, so it has been like 8 months since I asked about this and I FINALLY got around to trying this out.

No dice. I attached the pics. All it seems to do is a good job of darkening the maple. I tried this on the back of the piece I posted about initially.

I guess the black spots are NOT mineral stains?

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[sheldon pettit]

Sorry to hear it wasn;t sucessful Chris, it sure looked like mineral streaks to me. but as i said sometimes it works and sometimes not. At this point if it were me, i would just stain/dye if desired or clear it naturally and use touch up powders to blend it in ok?

[Chris Padilla]

I may try my hand at some inlaying!

[Randy Goodhew]

Chlorine based bleaches probably won't work on this problem.
Use an Oxalic Acid wood bleach, such as brand names DAP, Rainbow, Savogran or Liberon.
Most of the woodworking specialty stores carry these products.

I'm a chemist and a wood worker with 40+ years experience.

[sheldon pettit]

"oxalic acid" is a chelating agent, it's best use is to pick up ferric ions in the wood, this from what i can see is not an iron produced problem, why would you beleive it would take care of the problem?

[Chris Padilla]

So the black spec in the middle pic on the first post is the SAME black spec in the right pic in which I tried to dye it. In other words, the black spec runs through the thickness of the board...kind of like a limb.

[sheldon pettit]

Gotcha Chris, i know it's not something OA would take care of, not sure now just what it is, but if your prefer to router it out or cut it out and inlay, i will leave that up to you, just not sure that will look as good as artwork would, i know i could make it dissappear with powders and pearls as i went along with the finish, but i don't expect others to be able to do such unless they are pro touch up guys. Good luck which ever route you take though.