D/C covers

[Fred Sturm]

Mark Bolsius wrote:

> 
> Dampp-Chaser has tried a variety of materials for an under grand cover. . . I
> recently spoke to Roger Wheelock from Dampp-Chaser to see how the research
> was going.
> 
> He indicated that while the initial results were promising, after about
> three months there was a build up of moisture in the soundboard...not the
> result anyone wants!! 

When you think about it, moisture buildup is inevitable unless there is
an adequate amount of air exchange with the outside. A bottom cover will
tend to trap what moisture is added (generally positive), but will
impede getting rid of moisture with the dehumidifying rod. So it becomes
a closed system with moisture gradually added and very little removed. I
would guess the material would have to be permeable to moisture, or
discontiuous (with gaps either as holes or as space around the edges).
Something that would allow moisture exchange, but keep out the draft, as
you say.

> Meanwhile, the string cover has
> come up trumps, testing indicates an improvement in the moisture content
> range. You'd have to ask Roger or Bob Mair for the exact figures.

What kind of materials are used for string covers in these tests? Just
fabric, or something that is relatively impervious to moisture?

> 
> BTW to fix the cover on the back of an upright....pin pegs or Velcro spots.
> If you use velcro, you need to tack the spot onto the piano, so that if the
> glue fails, it still hangs in there.
> 
> ...and yes, it's Mylar
> 
> Cheers
> Mark Bolsius
> Bolsius Piano Services
> Canberra Australia

Many thanks for the response,
Fred Sturm
University of New Mexico