Floating soundboards

[John Hartman]

Jean-Jacques,

Sounds like you planing a lot of work on this Bluthners. It would be a 
good idea to check for plate cracks before investing more time and 
money. Most every Bluthners from this era I have seen had plate cracks 
of one sort or the other. Check the area were the struts intersect with 
the webbing near the agraffes. If you see something funny and are not 
sure what it is rub your finger over the area and feel for sharp edges 
or slight lateral shifts.

It's amazing how many technicians are unaware of these plate cracks, 
until of coarse they get worse during rebuilding or they find that some 
one in the past has added steal bars to the plate from underneath and 
has dug deep trenches in the pin block. I have been to many music stores 
and rebuilding shops were there are some of these old German grands 
proudly rebuilt for sale with high price tags as well. Almost every one 
with a cracked plate - some with as many as five cracks. The methods 
used to hide the defects are not effective past the first couple of 
tunings and soon become visible to the trained tech.

I was called in to examine one of these pianos, the client purchased it 
with no knowledge of the cracks and his technician who had been tuning 
it for years never saw them. I delivered the bad news and returned home. 
A few months later the client call me to say he had been awakened in the 
night to a load report - the cracks had all extended through the bars. 
The piano and his considerable investment were gone!

John Hartman

Jean-Jacques Granas wrote:
> Hello list,
>  
> I am slowly getting ready to restore an old (1896 as it turns out) 
> Bluthner 6'3'' grand.
>  
> I will most probably float the soundboard in the deep base. I won't need 
> to glue new ribs and there are none in the far corner that would 
> interfere. I will probably also replace the board (and ribs) as it has 
> collapsed and I am wondering just how long should this float (cut/rip) 
> should be. What are the criteria involved in deciding on the length of 
> the cut? How do factors such as thickness of the board, distance of bass 
> bridge to rim come into play here?
>  
> Another question I have been wondering about is whether anyone has ever 
> floated the soundboard at the high treble end, along the short side, 
> perpendicularly to the end of the bridge. What are the likely results of 
> such an experiment. Btw the treble end float idea is just theoretical 
> curiosity.
>  
> Can someone with experience in this matter share a few thoughts ?
>  
> Thanks,
>  
> Peace,
>  
> Jean-Jacques Granas
> Warsaw, Poland
>  



-- 
John Hartman RPT

John Hartman Pianos
[link redacted at request of site owner - Jul 25, 2015]
Rebuilding Steinway and Mason & Hamlin
Grand Pianos Since 1979