Compression ridges was :Do you dry the ribs, along with the board, prior to gluing ?

[Richard Brekne]

Hi all

    Greg says :

    Um, compression ridges are clearly broken fibers are they not?

I think we all, or nearly all are in agreement that compression ridges 
show an area of the soundboard that has been over stressed.  A thin line 
as it were representing a fraction of a precent of the area of the 
soundboard... and as such as significant in itself to the sound 
producing capabilities as your usual tension crack. 

They DO show clearly that the soundboard is under quite a bit of 
compression in general... I dont think however one can say that the 
appearance of a compression ridge or two defines a board that is on the 
whole destroyed by compression. Especially when they remain in ridge 
form for year after year and do not eventually yield a crack.

I have an example of an 35 year old Petrof with 3-4 ridges that is quite 
lively indeed.  This despite many many hours of use in a university 
setting.  No cracks... plenty of sustain... tho admittedly it no doubt 
had more life at some point. Still its a very nice sounding instrument.  
Newly rebuilt action ... the thing was picked out by one of the 
professors here for his primary instruction instrument.  And he could 
have had a brand new Yamaha C-6 from the showroom of the local dealer.  

Cheers
RicB