[pianotech] Accoya...bellytalk...no tuning allowed

jimialeggio jimialeggio at gmail.com
Wed Feb 2 08:38:32 MST 2011


My dear bellyheads,

I've been following a wood treatment process called acetylation with 
serious interest.

My interest is  2 fold.   One - for my sash/door building and other 
exterior wood applications, and two- for soundboard panels.

Sash wise, myself and many other exterior millwork guys, are trying to 
find replacements for the amazingly stable rot resistant, but 
disappearing Honduran Mahogany.

In this regard, a product called Accoya has been receiving some serious 
attention in the replacement mahogany front in this country very 
recently. It was developed by a Dutch company. Its radiata Pine 
(sustainable) that has undergone acetlyation. It has been around and 
been receiving real time testing for 10 yrs in Europe.

I'm not chemist, but the talk is that the hydroxyl groups naturally 
occurring in wood are converted to acetyle groups...for non-chemists 
like me, they say its like being treated with vineagar...a simple minded 
explanation but it gets the broad idea across, I think.   Anyway the 
result is that the wood retains its structural characteristics, gains a 
little density(unlike pressure treated wood which gains tonnage), but 
most importanly for me its dimensional stability is increased by 75%. 
Both real time testing and independent testing seems to bear this claim 
out.  Insects do not recognize the substance as wood,  and it doesn't 
support fungal growth.

here are some #'s:

Sitka   tangential shrinkage 7.5%, Accoya tangential  1.5%   (warranty 
maximum 2.5%)
Sitka   radial 4.3%, Accoya  radial .7%
Sitka density 450kg/m3, Accoya density 510 kg/m3
Sitka MOE 1.57, Accoya 1.27    white spruce 1.34, engleman spruce 1.28

my thinkings here bellywise are:

1-major reduction in seasonal reactivity of a soundboard panel
2-a stable substance that could be fabricated using our current standard 
wood shop techniques
2- in rc&s assemblies, it has not been satisfactorily  explained to me 
why the panel, which is not the structural member of the board has to be 
sitka
3- could sitka be acetlyated?

For your amusement  I offer http://www.accoya.com/  .    I have a pdf of 
the wood's properties which I would post, but I don't think I can post 
an attachment to the archives   You might try to get it here, 
http://www.accoya.com/accoya_downloads.asp or contact me and I'll send 
you the pdf.

By the way, this is a marketing free zone...I'm not a distributor of the 
stuff, and have no stake in selling it...just a wood guy interested in 
new developments.

Jim  I

Jim Ialeggio
grandpianosolutions.com
978- 425-9026
Shirley, MA



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