I've quite a bit of experience of hot melt adhesives in industry,
and over the years have experimented with different types on player
pianos.  Hot melts are just modern versions of traditional hot glues,
so they would seem a good choice for attaching striker pneumatics to
decks, for instance, especially since they can self-form a gasket
interlayer which can be easily and safely parted.

Hot melts need warm, dry, dust-free surfaces to bond well.  Some
adhere best to keyed (matt) surfaces, some to smooth.  They penetrate
no substrates except very porous fabrics and are usually easy to
peel off completely, so it isn't necessary to glaze boards to ensure
reversibility.

However, I found that although all hot melts hold a vast amount
of heat, most types gel too fast for unhurried application and
positioning -- certainly faster than traditional hot glue -- so
bond-strength is often compromised.

Also the general purpose, rather than engineering, types of hot melt
adhesives seem to shrink and become brittle over a year or two, and
bonds can fail suddenly.  Overall, no hot melt I tried bonded strongly
and certainly enough.

But thanks for the excellent 'Hot Melt Adhesives Technology Review'.
Emerging types may prove ideal, but currently I prefer the cool, calm
ease and reliability of RTV.

Paddy Handscombe
Wivenhoe, Essex, UK