Wood changed color after sanding

[David Houchens]

This is my first go with Cocobolo and I've seen wood change after sanding before. Just not quite this much. Usually it's just a little when the oxidized surface is removed.
Not sure if this is the same thing because it just happened in certain places.
Any ideas if the yellow will settle back anytime soon or will it occur over the long haul? Also will it happen under finish? You can see the difference.
Would a trip in my UV cabinet help?

[Paul Busman]

Cocobolo is notorious for changing color over time. Exposure to UV light contributes to it, and there's no good way to stop it. Do a Google search for "cocobolo color change" and you'll find mountains of information, but not a lot of real help.
I love Cocobolo for making penny whistles. The grain can be beautifully outrageous and it's a joy to machine. However, there's no way to know how much it will change in the future. I have one that I made for myself years ago from a beautiful piece and now it's darn near black. I have an Irish flute that was made for me by my whistle making mentor, and that's pretty black too despite spending most of it's life in the dark of it's case.
Word of caution-- Cocobolo is one of the most allergenic woods. Take extra precautions to protect your skin from dust, and from breathing the dust. A woodworker I know told me "there are two types of woodworker: those that are allergic to cocobolo, and those who aren't allergic to cocobolo yet".

[tree]

I've worked with air dried billets of Osage orange (Maclura pomifera) that went from brown to startling bright yellow when planed.

It does return to brown as the fresh surface oxides. My guess is that your Cocobolo will do the same.

Wood continues to oxidize under finish, but I can't tell you the rate of color change. I just know that it happens over time.

[tonydxn]

I endorse everything that Paul Busman said, including his warnings about the toxicity of cocobolo. Gorgeous wood, but as poisonous as hell. Protect yourself.

The only thing I would add is that the yellow appearance of the freshly-sanded wood will change as soon as you put some finish on it. It will look more brown straight away. After that, it will darken slowly.

[David Houchens]

Thanks to all. Actually the yellow/orange was the starting color. The light purpleish brown is the sanded color. I was just hoping it would return to all look alike sooner than it probably will. As long as the guy buying the guitar is ok, I'm ok. I guess we'll just have to be anyhow.

[Marty Jacobson]

It will even out dramatically in the first month, and then more slowly over time. I had some that was bright orange, looks like this now 15 years later.


Most of it is much darker than this, though.

[David Houchens]

Thanks Marty. I'm glad to hear it will start coming back some soon. I think this set will look real nice in shades of brown.

[tonydxn]

Here is a shot of a ukulele I made last year. The finish is water-based acrylic. I would expect your wood to look like this, pretty much. It will darken over time.

[Paul Busman]

I haven't tried it, but I wonder if applying a finish to both sides of the would would help limit oxidation by reducing exposure to oxygen. That would probably change the acoustics unfortunately. I may try it next time I make a cocobolo whistle.Acoustics are not that significant in my thin walled .5"ID tubes.Maybe a couple of coats of sanding sealer?

[David Houchens]

Well, almost all the pinkish, purplish color has changed back to the yellow/orange after wetting and bending. Thanks to all for your help and support as usual.
This is some of the beautiful Cocobolo I purchased from James Condino last year. Thanks again James.
I have been waiting for the right project that would really make it stand out.
This is going to be a 14 fret 00-45 and I was concerned the buyer might not like the color change. I'm sure he has seen his older guitars darken over time and would be fine either way. Again, Thanks to all of you for your quick replys.