Re: Sealing Pouches
By Douglas K. Rhodes
The lively discussion regarding pouch sealing techniques is great, and not likely to end soon. I am dismayed however, that nobody has questioned any of the sealants in terms of the first standard by which responsible work is judged, that being the requirement that the technique or material not cause any degradation of non-replaceable parts. It seems to me this has to be the very first goal of the restorer. White glue, after years of indiscriminant use, has finally been identified as an unacceptable material for rebuilding, since removing it generally causes damage to the wood. I would suggest that some of the proposed sealants are even worse.
Mink oil has a time-honored reputation for eventually ungluing the pouch, leaving behind an oily mess on the wood.
Silicone, unless I am mistaken, _does_ migrate, and will migrate across contiguous surfaces until it is one molecule thick, or runs out of surface, whichever occurs first. Piano rebuilders (and refinishers) have known for more than a decade that silicone oils and sprays are anathema to the workings of a piano action, and those materials have all but disappeared from our tool kits in favor of Teflon or other lubricants.
I don't like rubber cement. It is not rubber, and it can turn to cement, but it is _not_ a contaminant.
The proof of all this might be to treat pieces of pouch leather with the various proposed sealants, and leave them undisturbed face up on a sheet of glass. Inspection after several months will reveal which ones have left behind a residue that made its way to the glass from the top surface of the leather. The ones that do are unacceptable.
Doug Rhodes
RTT - The Piano Technicians Guild
Victoria, British Columbia |
(Message sent Wed 10 Apr 1996, 21:15:00 GMT, from time zone GMT-0700.) |
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