Has Anyone Ever Seen This Regarding Cocobolo?

J

JRiefer

Joined
Jan 20, 2000
Messages
29

I have a decent supply of exhibition cocobolo for future handles as well as some abalone. Here's a mystery I stumbled onto yesterday.

I took ten 5" blocks of beautiful cocobolo and sanded 80 - 600 grit before buffing, wanting to see what I really had. I started with REDDISH ORANGE stock with plenty of black swirling figure. As I sanded, the nice red-orange color gradually disappeared and turned into a purple and cream color (black figure remained constant).

Where the h... did the red-orange color go? Why was it just on the surface?

Looking at the freshly sawed end-grain, all around the blocks edge, a 1/16" line of orange showed, then inside the purple and cream.

Could my supplier have possiby dipped the coco blocks into red-orange dye?

Thanks for your opinions.

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Joe

If at first you don't succeed, then skydiving isn't for you.
 
I agree, heat will change it pretty easily. It's like purple heart that has been burned, it goes from a dark marune/purple or brown, to a very bright, glazed purple.

Crazy stuff.

Nick
 
Be sure you use fresh sharp belts to grind this stuff. You can seal it with a product called Sealacell from Woodcrafters. That will keep it from turning colors on you.
 
I believe that the color change has to do with an oxidation process...as do most exotic woods.

Jeff Jenness
 
i dont think it is the heat as much as oxidation......changes the color of the surface rather quickly......
 
Thanks Guys.

As a few of you might remember with that pink ivory and stabilization thread, I'm a firm believer in fresh sharp belts. I went from new 50, not 80, to 80, 120, 320 and 600 grits, pressing lightly and turning often. It's not heat build-up. I've always taken my best wood blocks and finish them A to Z including Fix-It and Renaissance wax (to observe quality and color retention, mostly to see what I really have). I'm refering to 200 - 300 5" and 6" x 1 1/2" blocks of coco. I definately got the same final shade of color as the fresh cut end grain (new saw too).

Bob, I will try that Sealacell to keep the coco from turning dark over time.

Jens, I'll also try the light and air procedure. (real nice knife on your site)

Also thanks Phil and Nick.

The thing that puzzles me is why on the fresh cut end of every one (same supplier and shipment) have a 1/16" rim of orange around the purple/cream interior. It sure looks like the exterior has been dyed.

One thing I didn't mention, this stuff was from a very large coco importer with a fresh monthly supply from Western Mexico. (I've ordered every month for a year, great person) But this time I asked for some product bordering the sapwood near the outside edge. I like the occasional multiple colored layers you frequently find there. That doesn't explain the thin 1/16" rim of red-orange on the outside.

Tom, I know oxidation changes exotic wood like pink ivory (brown) and especially cocobolo (turns darker). But these blocks changed from orange and black figure to purple/cream and black figure right before my eyes in less than a minute as I sanded deeper. I'm sure it's not oxidation. If I had pics, it would be easier explaining. BTW, your piece of curly Koa is still one of my favorites.

I sure would appreciate any additional input from any of you...I'm really baffled.

Thanks again.





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Joe

If at first you don't succeed, then skydiving isn't for you.
 
A little tip to all of you who grind cocobola. If you are perspiring while grinding, it would defintely be to your advantage to wear protectve clothing. The flour like dust from grinding is a toxic very much in the manner of poison ivy.You might be one of the lucky ones who are not allergic . If you are allergic to the dust you can become quite miserable. Each succeeding
case is greater to the previous one and keeps escalating in severity.

Sandy
 
Hello,

yep nasty stuff it is, a great maker i know named Rod Chappel had a bad bout of skin cancer on the hands from years of grinding cocobolo and having the dust on his hands,,, he may have just had a tendency for it being toxic to his particular body make up, but i dont take chances with it and wear latex gloves grinding it with long sleave shirt and respirator always, which you should wear anyway.

As for cocobolo i kind of like the different Hues of brown, purple and cream colors in it that you find somtimes, adds character.

my .02
Allen

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Allen Blade
Spokane,WA USA

" You can make great knives and sell a few, Or make Great AFFORDABLE knives and sell many"
WEB SITE : http://www.geocities.com/bladecutlery/blade_cutlery_site001.htm
 
I'll bet by now the color on the surface has returned to what you had originally. Many of the darker hardwoods display a diferent color when you expose new interior wood which then changes (usually darkens or fades)upon exposure to the air and light. As you observed, this oxidation penetrates a short distance into the woods surface.

Many woods contain irritating resins and should be worked with protection, both dermal and respiratory. Allergic reactions have been experienced by myself and other knifemakers from cocogolo, rosewood, desert ironwood, and other common knife handle material.
 
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