[CAUT] finish/moisture barrier

[Bob Hohf]

According to research done at the Forest Products Laboratory in Madison, WI,
the only wood finish that provides a true moisture barrier is epoxy.  My
source on this is a class at a Wisconsin Days Seminar in the 80s taught by a
Forest Products researcher.  For information on the relative moisture
resistance of various finishes, see Table 16-2 of Wood Handbook: Wood as an
Engineering Material, published by the Forest Products Lab.

 

Bob Hohf

 

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Brent
Fischer
Sent: Tuesday, February 15, 2011 10:44 PM
To: caut at ptg.org
Subject: Re: [CAUT] Steinway rebuilds

 


Ron,

  

   The research I mentioned was pertaining to permeability issues , sorry

that wasn't clearly stated. The reports that you claim about increases in

stability are probably design related not finish differences, and are

just as speculative as me saying lacquered boards need double

duty damp-chasers. If I indeed implied that varnish is a determining
stability

factor, well, I'll back the truck up on that one.  The real question I have 

is if you know that varnish provides a better moisture barrier in the first 

place, why use a coating with less moisture sealing properties? 

Because it's easier?

 

 


--- On Tue, 2/15/11, Ron Nossaman <rnossaman at cox.net> wrote:


From: Ron Nossaman <rnossaman at cox.net>
Subject: Re: [CAUT] Steinway rebuilds
To: caut at ptg.org
Date: Tuesday, February 15, 2011, 8:43 PM

On 2/15/2011 9:18 PM, Brent Fischer wrote:
> 
> I'm going to take the high road on responding. Research proves my
> point, I'm just repeating it.

Research? On piano tuning stability as a result of using varnish instead of
lacquer on soundboards? That would make entertaining reading.


> Proving stability differences is just a mute point.

Well, no. That seems to be exactly the point.


> However, too many rebuilders use lacquer on
> boards because it's easy, not because it's in the best interest of
> the instrument.

At least a couple of techs providing service to my lacquered soundboard
redesigns have reported that they are notably more stable than the original.
There are a number of parameters for tuning stability in design and build of
soundboards that are argued by non designers and builders of soundboards,
but there is ample evidence that varnish is not the magic ingredient that
provides stability.
Ron N

 

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