Soundboard Clamping for Downbearing

[Farrell]

Hopefully others will provide some input for some of your other questions, but one thing caught my attention in your post. You wrote:
  
".....and placing new crowned ones, drying the board and the ribs carefully to a MC as low as possible and then gluing and clamping them together."

Drying the board as much as possible will permanently damage the wood. It is not difficult to dry the board WAY BEYOND that desired. Most soundboard designs call for a EMC of 4.5% to 6% for rib glue-up. I think the compression crowned boards will tend to the lower end of that range and the rib crowned boards will tend to the upper range.

Terry Farrell

> So if you want to know, I'm going to restart, ie taking of the ribs
> whith a plane and placing new crowned ones, drying the board and the
> ribs carefully to a MC as low as possible and then gluing and clamping
> them together.
> The "only" problem I still have: how much crown should I give to the
> beams of my press: none, and arc of +/-18m for the longest ones and
> +/-15 for the shortest ones, (like the ribs are precrowned),  +  for
> having  more  crown at the end?  (How much should one have with a new
> board anyway?) Can somebody me tell that please?  I only know that the
> uncrowned beams of my press give about one cm of crown when I'm blowing
> the hoses. 
>  
>  
> I also want to thank all of you who have discussed this item.  Do not
> think I feel blamed but it was hard at some points.  I have learned my
> lesson and made my conclusions that you can read above.  But I think
> this was the money I have to pay for.  And after all, in doing 15 years
> of restoration of piano's, I have only to restart 2 times a job.  I
> think that's not bad.  And also, making soundboards, I love it more and
> more.
>  
> Peter
>  
> 
> 
>