Ray Bates is asking if zephyr skin is airtight.  We have been using
zephyr skin to recover bellows on bird boxes and bird cages for the
last 20+ years.  In the beginning I would coat the skin on both sides
with shellac thinned out with alcohol at a 50-50 level and then, after
the shellac dried, would dust it with pumice stone.  We did this on
both sides of the skin in the belief that we were covering holes.  We
did experience an improvement in adhesion using the various glues on
the zephyr skin to the wood and plastic frames of the bellows.

We have eliminated the coating of the shellac and use the zephyr skin
as it comes to us.  After covering the reservoir side of the bellows
we check for air leaks using soapy water.  If we find a leak we then
use a leather cement to cover the opening.  We have never used rubber
cement as it does not provide the adhesion that we are looking for.
We do the same thing for the pumping side of the bellows checking for
leaks during pumping.  At the end of the process we have a bellows
that is nearly airtight.

This has been our experience over the last 20+ years and I hope it
helps.

Regards,
Tony Ciuffini
The musical box, Dr.