Compression Ridges

[Larry J Messerly]

Joel,
I noticed that one of the grands in my store was developing a pressure
ridge (humidity was 65%).  I installed a DamppChaser unit and it was gone
the next day!  Can you tell that I like DamppChasser systems!

I especially suggest them to new clients bringing pianos from a more
humid climate to Arizona.  I find a lot of recently tuned pianos moved
here from California a quarter step or more flat.  It happens
consistently enough that I do not think that the clients are mistaken on
when the pianos were last tuned.

Humidity was so high because I only have an evaporative cooler in my
store.  Winter time, spring and fall humidity is usually in the 20 to 40%
range.

Larry Messerly, RPT
Prescott/Phoenix (store is in Prescott)

On Mon, 4 Sep 2000 20:28:56 EDT JCSwafford@AOL.COM writes:
> Hello List,
> 
> I recently inspected a new Mason & Hamlin Model A for a customer. It 
> was a 
> fantastic piano, but I found several ridges in the soundboard. I 
> could feel 
> them as I ran my hand across the underside of the soundboard. They 
> protruded 
> upwards. 
> 
> I mentioned to the customer that in my experience these ridges are 
> fairly 
> common in pianos built today with solid spruce boards and was the 
> subject of 
> controversy between Steinway and a dealer not long ago. I told her I 
> wasn't 
> very knowledgeable about them and they may not even be compression 
> ridges at 
> all, but irregularities in the joining of the planks of spruce when 
> the 
> soundboard is constructed. I told her she was not likely to have any 
> problems 
> from them in the future and I would consult the list to order to 
> give her a 
> well rounded opinion about them. 
> 
> I explained that compression ridges occur when the board is dried to 
> much in 
> the kiln before installation and the installation is to tight to the 
> rim of 
> the piano. The ridges occur when EMC is returned to the board not 
> giving it 
> enough room to expand without compressing. 
> 
> I haven't studied soundboards, their preparation or installation 
> techniques.
> 
> May be I can get some feedback from some of you knowledgeable 
> rebuilders or 
> intellectuals out there.
> 
> Thanks for your help in advance.
> 
> Joel Swafford, RPT
> 
>