B. Hopf wrote: > It has always seemed to me that one of the functions the cap serves is to > cover the multiple glue joints between the bent laminations and present just > one joint to the atmosphere. Bridge capping became practice at a time when th > only glue available was hot hide glue, a glue where failure is directly > related to exposure to the atmosphere. A laminated bridge glued with hide > glue would be many times more resistant to failure with a cap. This practice > [....] > This explanation doesn't seem to be consistent with the many extant pianos, e.g. Grafs from 1820, that have bridges which look exactly as they did when installed 170 years ago. The laminations are perfectly intact in these Grafs. Glue-joint failure in hide-glues is related to moisture and only a very humid atmosphere can affect this...I don't recall ever seeing a bridge cap on an early piano...this may be a 20th C habit. Or perhaps North American pianos are different in this respect (I am not as familiar with these). Stephen Birkett (Fortepianos) Authentic Reproductions of 18th and 19th Century Pianos Waterloo, Ontario, Canada tel: 519-885-2228 fax: 519-763-4686
This PTG archive page provided courtesy of Moy Piano Service, LLC