In MMD 110308 Tim Crake says, "Patrick's practice of 'sealing stack
and pneumatic boards first with water-soluble PVA to achieve a better
RTV bond and to completely protect the original wood of the deck' has
a drawback.  By sealing the original wood with PVA, the repairer
confines future repair of the player to these modern adhesives only."

This is incorrect.  PVA is entirely water soluble and can be easily
and completely removed with the same techniques as animal glues are
removed.  This is why PVA is invariably used in relining valuable
canvases, which have in the past suffered much damage from animal glue.
PVA is anyway compatible with animal glue and will not prevent it
adhering.

It seems that few on MMD have bothered to grasp that PVA is absolutely
_not_ the same as PVC-E which becomes water insoluble when set.  I do
not know how much clearer I can be about this important distinction.

I mentioned cyanoacrylates in violin making because I had seen
a mention of it a while back by a progressive young maker on a TV
programme, and I'm sure some of the big Japanese makers use it.  There
are many types of cyanoacrylates, and some intended for bonding wood
give a fast-setting weak brittle joint like animal glues, but don't
need to be kept hot, and are also water soluble.

I'm surprised that Tim says that the plate/rib joint is not acoustically
important, as a violin maker once told me completely the opposite!  An
equivalent hard non-lossy joint between a piano soundboard and the rim
certainly contributes to the sound quality of top instruments.

Tim says "that glue joints are reversible is really the overriding
and commendable principle."  I concur, which is why I use PVA and RTV.
The original stack makers certainly never intended their joints to come
apart easily, hence the terrible damage so common during rebuilding.

Patrick Handscombe
Wivenhoe, Essex, UK