vertical backcover: Gortex?

[Don]

Hi,

Their research (or so I have heard) on grand pianos showed that a grill
cloth was a requirement. Otherwise after a time the humidity levels would
start climbing inside the grand piano. This effect doesn't happen on
uprights with back covers. My own research shows about a 4 to 10 fold
improvement using 6 mil poly as a back cover for uprights. I have no data
on cloth back covers.

I originally "super sealed" the back covers using duct tape and push pins.
After a couple of years the duct tape had failed on a few installs but the
stability results were still just fine. I then started installing with just
staples from a common garden variety wood staple gun.

My first bottom covers showed dramatic improvements to stability in grand
pianos. For example a Yamaha G2 which was equipped for many years with a 6
part system when from a lowest plain steel string "swing" of 65 cents to
less than 4 cents. The client was able to go from tuning every six months
to yearly service, and have a piano that sounds well for most of the year.

 

At 01:18 PM 29/08/2004 -0700, you wrote:
>
>       It's interesting that DC first recommended mylar then switched to
>grill. These are two very different types of materials. They must have
>decided that breathablity was an issue. I thought maybe Gortex or some
>similar microporous material might be the best of both worlds.    & D over
>the years. I would be interested to see all the documentation on what tests
>they ran and what all the results were.

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.

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