Dear all,  There has been much debate over the years regarding Duo-Art
accordion re-covering, both the dimensions and the material to be used.
I have been using a formula of dimensions, very similar to those
mentioned by Paddy Handscombe, for many years with complete success.

However, in all the original Duo-Art pianos that I have restored,
not one of them has had accordions covered in anything other than
perfection leather, as per the stack pouches.  In one of them (a Steck
upright in an inlaid case supplied new to Mr. Sharp of the Sharp's
Toffee family in 1923) the leather was maroon in colour and was dated
on the inside.

The reason for this choice of material is most likely to be the
fact that Duo-Art accordions are operated at a suction level which
approaches that produced by the pump -- it is essentially un-regulated.
Thin tosh, as found on striker pneumatics, is only subjected to
carefully regulated suction by means of the expression box.

In my experience, covering accordions with tosh and subjecting them to
this high-level vacuum leads to their having to be re-covered very much
sooner than their leather-covered counterparts, because the rubberizing
fails at the folding pleats.  Having re-covered a pair (or a single, in
the case of a half Duo-Art), and obviously sealing the leather to make
it as vacuum-tight as possible, I stretch them for a few days using a
simple jig.  The piano soon starts to fail during soft playing if this
isn't done.

I have seen several accordions that have been carefully re-covered, but
the stop cushions have been re-covered using soft thick felt.  The piano
will gradually play louder and louder due to the stop screws burying
themselves in the soft felt.  Thin bushing cloth or bearing cloth was
the original material used by Aeolian.

Kind regards,
Mike Boyd