water based finishing

[Farrell]

I would dare speculate that if indeed wood was rotting under the finish, that the wood was excessively moist when the finish was applied. Also, what appears to be rot (were you able to actually check and see if the wood was deteriorating due to fungal growth?) may have been evidence of moisture and perhaps a less than perfect bond of the finish to the wood.

Polyurethanes in general are not as "airtight" as some epoxies, and coating epoxies are used in many applications for the primary reason to limit the ability of water/moisture to penetrate through the finish. This does not cause the wood to rot. Again, you might have problems with rot if the wood was too moist to begin with. You can also have problems if the barrier coat is breached, and water is able to soak into the wood from that one spot (most often a problem if the wood is in direct contact with water) - the wood could start to rot in this case because it is let in, but not able to escape easily.

I don't think the characteristics of any finish alone will cause properly prepared wood to rot. Please correct me if I am wrong.

Terry Farrell
  
----- Original Message ----- 
From: "D.L. Bullock" <dlbullock@att.net>
To: "Pianotech@Ptg. Org" <pianotech@ptg.org>
Sent: Monday, June 10, 2002 1:45 AM
Subject: Re: water based finishing


> I was talking about regular pianos finished with polyurethane varnish.  They
> were not outdoors. the gray streaks were the rotting wood and not in the
> finish.
> 
> DLB
> 
> >writes:
> >> I know the problem with Polyurethane Varnishes is they are so airtight
> >they rot
> >> the wood underneath with gray streaks showing after 5-10 years.
> >
> >Hi D.L. -
> >
> >I am not familiar with this phenomenon.
> >Is this on wood that is outdoors?
> >Are the grey streaks in the wood or in the finish?
> >Can you elaborate?
> >
> >Curious...
> >
> >Mark Potter
> >bases-loaded@juno.com
>