Question about high gloss finishes

[Don Mannino]

Jim Bryant submitted:

>Keith;
"Do high gloss finishes allow the wood to breathe?"

ANS: NO.
Most latter day  polyester finishes are applied to manufactured substrate,
i.e. high grade particle board.
 Wood underneath a polyester finish cannot breathe as we know it and develops
cracks in the finish after a period of time. While the core of a lid or
fallboard or music rack or rim may be wood/plywood there is a layer of
manufactured highdensity substrate that is actually finished with the
polyester due to the superior stability of this substrate over wood. Ever
wonder why new Gloss piano lids are so heavy compared to older models?
 Quite a few case parts on high gloss pianos are not even substrate but
actually a high density plastic.
Keith maybe some manf. rep will jump in and explain the reasoning better than
I can.<

Reply:

- There is no finish that is 100% impervious to air and moisture. Polyester
resin is close, but I don't know just how close.
- It is irresponsible to state that wood under a polyester finish cannot breathe
and will cause cracks in the finish. This is not in the least bit true - many,
many pianos with polyester finishes are around that are 30+ years old, have
lived in difficult climates, and are flawless. Any finish material if put on
wrong, formulated wrong, or abused by poor conditions will fail and crack - all
of us have seen varnishes and lacquers crack, and polyester generally fares
better than these.  It angers me to read such an incorrect, blanket statement
unfounded in fact.
- I am very familiar with the manufacturing processes of 2 brands of pianos
which have polyester finishes. Neither one has a "high grade particle board"
substrate under the finish. Young Chang seals the wood with polyurathane sealer,
then applies thick layers of polyester resin directly to the sealer / wood. It
is built up very thick, then sanded smooth and polished. Kawai applies a
lamination of a backer material (which is itself made of a phenolic resin) to
create a stable base, then applies a very uniform and smooth polyester coating,
which is then lightly sanded and buffed.  There is no particle board used.
- It is irresponsible to identify materials based on the weight of a lid!
- Keep in mind that satin finishes are also often polyester - one shouldn't
single out high gloss only as being polyester.

Don Mannino RPT
74473.624@compuserve.com