question about finishing amboyna burl

[Aaron at Wingerts Woodworks]

Ran into something wierd and wanted to see if any of you guys have had this happen.  I recently picked up some very nice amboyna burl and made a gorgeous duck whistle from it.  Hadn't turned amboyna before, and I don't like to send a call out with a wood/finish combination that I haven't dealt with before, so this whistle is for me.  I put a coat of tung oil on it, as I do on a lot of my calls.  Good thing it didn't go to a customer.  About a week later, the call was sitting on the kitchen window sill and I noticed it looked dusty.  Picked it up and it had a film all over it, which I'd liken to a very fine grey-ish powder.  It looked like it had been rolled in portland cement powder.  It wiped right off, but appears to be coming back. 

I know the wood is dry.
I know the tung oil is not spoiled. 

I've seen Argentinian lignum vitae grow a crystalline "fuzz" on the unfinished parts of the toneboards of a few calls I've made.  Like amboyna burl, it also has a really spicy/pungent scent.  I'm wondering if the wood is off-gassing or releasing some sort of oil? 

Anyone?  Anyone?   

[tolbndfishin]

Does your wife has a stash of portland cement she's dusting it with a little at a time to build it up?  Cause If that was the case, I think we'd all laugh a little (I know I would, unlike when i think my wife handed one of my duck calls to the dog, a couple years ago to give him something to chew on).  If only it were that simple....  I'm curious myself, while i havent even seen this wood in person, I do plan to one day work with some, and it'd be nice to know what to watch for.

Dan

[Bob from Eames Custom Calls]

I've seen a similar type of thing happen with tung oil on a chunk of mountain mahogany one time, but I've never played with the amboynia burl. I'm pretty sure that what I saw was due to a higher than normal moisture level in the wood reacting to the oil, but I could be mistaken.

 Sorry I couldn't be more help!

 Bob

[Joe aka COLD @ J. A. Kolter Calls]

Same thing happened to me Aaron with a finished duck call that had ambroyna burl panels.  It cleaned off with some hand buffing, and then re-appeared a month later.  I've since sold the call so don't know how much more of an issue it is.  I actually think it is a live and living decay type mold from within the wood fibers.

[Chris at Owens Custom Calls]

I just finished a barrel made from that but i used CA.  Hope its just a reaction to the oil, but i'll be keeping a close eye on it

[CScallmaker]

I've had it happen on lignin vitae with Tung oil before and it looked exactly like your describing I guess it's because it kept releasing oil from the wood after I wiped with acetone and before the Tung oil dried same thing may be happening here

[BigB]

Cocobolo has done that to me as well.

Brian

[tolbndfishin]

I've figured it out.  Chupacabra larvae.  The eggs are implanted into the wood after the tree hits about 4-5 years old, then once the tree is cut and finished with tung oil in the form of a game call, they start to grow hair before hatching.         No?  Sorry for the    Was just trying to throw ideas out there, because it seems as though many of you have had this problem.  If you cant tell, Im antsy about the reason for this, and have been googling all day in btwn work.  Sometimes my overwhelming boredom takes over and i get fixated on something like this, and become exceedingly curious.  Im hoping someone has an explanation soon, or I may not sleep very well tonight, or have dreams about chupacabra larvae.  (I bet you mods and admin on the site never expected chupacabra to come up in conversation here, so my apologies)

Dan

[Aaron at Wingerts Woodworks]

Thanks for the replies thus far guys.  Seems that I'm not the only one that's experienced this, which I guess is somewhat of a relief.  The next one will be CA finished, just to see what happens.  Sure is expensive stuff to experiment with. 

Dan, I don't think they have a chupacabra problem in Laos where the amboyna burl comes from, but that might explain the problem with Brian's Mexican cocobolo.  Wise guy. 

[BigB]

Dave (HuntnCarve) I'm sure will have an answer. I think I have read before his explanation on why it happens on cocobolo. I can't wait to read his response, as I always learn something with each one.

Brian

[tolbndfishin]

   I resemble that remark.   I am curious though, it seems like a strange problem, and i wouldn't have expected an oil finish to cause that.  Just to toss ideas out, could it be that tung oil isnt mixing/geehawing with whatever other oils and the combination is reacting and causing the "dust" you speak of?  Like mixing a bunch of cleaning chemicals from under the kitchen sink....  Not so much of an oil and water type of seperation, but more of a "this is what you get when you combine "A" with "B" "   

Or even could be something on the oil/water concept in that the tung oil causes the natural oils, or a component within those oils, in those woods to be displaced, and because the properties change it becomes the dust on the surface?  (Theorycrafting at it's finest, and you ought to now be able to tell how much I've thought about this today)

Btw, i dont know if any of this could actually be happening, just getting the brain moving...

Dan

[tolbndfishin]

Poor Brian, Aaron says you have a chupacabra problem...

[Bob from Eames Custom Calls]

Na, turns out it was just a shaved rat that jumped out of a box of bananas....

 Bob

[Brian Watts Custom Calls]

Thanks for the replies thus far guys.  Seems that I'm not the only one that's experienced this, which I guess is somewhat of a relief.  The next one will be CA finished, just to see what happens.  Sure is expensive stuff to experiment with. 

Dan, I don't think they have a chupacabra problem in Laos where the amboyna burl comes from, but that might explain the problem with Brian's Mexican cocobolo.  Wise guy.

i turn alot of amboyna burl  and finish with  CA and never had a problem yet ..

[HuntnCarve]

The technical definition is called "blooming".  It's a chemical reaction between the oil finish and the natural extractives in the wood.  Exotics have all kinds of extractives, some water soluable, some that dissolve in solvents-(oil based finishes contain some mild solvents). I'm not 100% certain, but I believe an oxidization layer (that greyish/white matter you've been seeing) forms on the surface when the oils react in the presense of air. -That oil finish no matter how thick, does not prevent air from moving in and out of the wood.  In a dry environment a gradient is formed that tends to pull moisture (remember our water soluable extractives and oils) toward the dry surface.  Just like a vacuum.  So there is a constant march of goodies from the innards of our call, to the outer surfaces. The good news is that it will eventually subside.  The bad news is that no one knows when?  So you just have to keep wiping it off. Just part of the baggage when using exotic species. -[Warning.  Some folks have terrible reactions to these oils and extractives!]
I believe a CA finish will do a much better job of preventing this problem, as it is not as permeable. 

HuntnCarve
Dave