remove possible mold from koa wood

G

gatorforge

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Jul 2, 2010
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I just got some koa wood in today, and i got a little water on it, and immediately dried it off, when i went to look at it a little later it was covered in green that doesn't seem to sand off or clean off. I'm not quite sure what to do next i can't ditch the wood because its expensive and I have a knife ready to put it on. Any ideas on how to clean it up or get rid of the green? Here are the pics.

koagreen2.jpg


koagreen1.jpg
 
Sounds like a little mildew. If you take some lysol and spray them it will usually kill the mildew. Or 1/2 bleach and water but will lighten the color a bit.

Worse case it will add a little color to the scales. The mildew won't spread after the wood is finished and sealed.
 
Mildew won't happen that fast nor penetrate that deep for the most part. Mold and mildew require specific environments to grow.

More likely your water or wood came into metal contamination or some other chemical. Nothing to do, but sand thru it maybe if that's the case. If you put bleach on it you risk likely getting ugly light blotches of color because it's heartwood.. Most exotics react different to bleaching agents than sap woods like maple.

Curiosity makes me ask what those scales cost. Not acrylic infused (stabilized)?
 
I wonder if it's the chemicals in the water supply that reacted with the wood.

Luthiers who use koa often use distilled water to spritz their side wood before bending so it doesn't react with the stuff found in many municipal water supplies.

I don't have any good solution for this set of wood, but good luck with it. That koa will look dazzling once finished. The figure is fantastic.
 
The wood could have been "stabilized" in something that is not an acrylic resin. Many internet sellers use all sorts of things to "stabilize" the wood they sell. Water may lift these chemicals right out of the wood ( not very stable,is it).

I would dry the wood well for a week or two. Sand the surfaces flat and use the wood as you intended. When the shaping is done, most likely the discoloration will be gone. Once shaped and sanded, seal the wood with a quality finish bu thinning the finish and applying many layers. Apply the finish, let it soak in for a few minutes, wipe off, let dry overnight, sand with 600 grit paper, clean off dust....repeat until the surface is completely sealed and smooth. It may take weeks to get it done, but that is what quality work requires.
 
PB Wilson said:
I wonder if it's the chemicals in the water supply that reacted with the wood.

Luthiers who use koa often use distilled water to spritz their side wood before bending so it doesn't react with the stuff found in many municipal water supplies.
Click to expand...

Good point!!!! Those spots can develop on koa guitar sides when hot bending with water spritz. Putting parchment paper between the koa and metal mold seems to eliminate the problem. Those spots are sanded out. Can't be of any more help without some feed back from the OP.
 
Hey the lysol actually worked pretty well and got rid of most of it. The water that got on it was from the tap, so in the future I will have to be much more careful with it.
Larry, The scales cast $20 for the set without shipping, which compared to most of the wood I buy is fairly expensive, and no they weren't stabilized.
Bladsmith, I do intend to finish it very well, I would prefer not to have this problem again thanks for the finishing tips. What finish would you suggest by the way?
 
I noticed a similar thing happen with a board of koa when I wetted it to see the figure. I'll see if I can get it to happen again.

Phillip
 
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