Restoration Report

Copyright © 2003 CBH

on the spine replacement of the
Michael Thomas French Double Harpsichord in an antique case
privately owned in Singapore

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Australasia map: Singapore 11K jpeg


When tuning the harpsichord at home in Singapore early January 2002, the owner noticed the spine side of the keywell was very flimsy. Inspection revealed that the spine was seriously weakened by termites, and the infestation appeared to be still active.

The instrument was fumigated, crated, airfreighted, and quarantined on arrival in Sydney prior to delivery to the workshop.

Termite infested harpsichord spine 19K jpeg

Termites in harpsichord part 8K jpeg

Insect identification
Several specimens of the dead insects and their bolus were sent to Dr Richard Milner (entomologist late of the CSIRO—and a keen recorder player and Past President of the Canberra Recorder & Early Music Society) for identification, and were returned as Cryptotermes sp, either C. domesticus or C. dudleyi.

Singaporean drywood termites are particularly dangerous. At times these insects are capable of just flying in and establishing a colony in any piece of wood in your home. They require neither decayed wood, nor wood that is in contact with moisture.

Removal of the existing spine
The degree of damage to the spine made it necessary to replace it in its entirety, a most interesting and rarely-undertaken job as the spine is quite literally the very backbone of the instrument.

Complete replacement of the spine was only practical in this instrument because of the substantial case structure from Dolmetsch, with slightly thicker than normal liners, a wrestplank horse arrangement with integral keyend blocks, as well as a bottom reinforcement probably dating from one of the European restorations of the 1980s.

Damaged harpsichord spine 24K jpeg
Harpsichord with spine removed 30K jpeg

The string tension was reduced, and the eaten spine carefully removed from the structure of the case. The soundboard and its associated spine moulding remained in place throughout the repair. It was established that the infestation was largely confined to the wood of the spine and the short beech block spanning the gap under the bass end of the registers. Damaged areas of the spine liner were cleaned and filled with epoxy compound to ensure sufficient strength.

Attachment of the new spine
A new spine was prepared in European lime Tilia vulgaris. In the earlier arrangement, there was no possibility of removing the registers without destringing the harpsichord, so opportunity was taken to include a spine window for future convenience. The distortion of the old harpsichord case had to be accounted for. A clamping method was devized using bench-mounted cams to allow the replacement spine to be firmly pressed against the bottom of the case while the glue dried. Traditional cabinetmaker’s screw clamps were able to be used to clamp the spine against the soundboard moulding and liner, and a bar clamp was used across the instrument at the wrestplank.

Attachment of replacement harpsichord spine 26K jpeg

Bass wrestplank view with replacement case papers 19K jpeg

The bare spine was primed, handpainted green using oil-based paints, and varnished to match the existing decoration on the case exterior. Printed Flemish papers were prepared and aged to seamlessly match the papers remaining on the soundboard rim and keywell of the instrument.

Stringing & Action
The action was installed, the existing strings brought up to pitch, and the instrument regulated.

The instrument was packed for return by airfreight to Singapore in April 2003.

After reacclimatization, the harpsichord was briefly checked during an Asian maintenance tour in late May 2003. The repair was judged a success by the owner, with increased tuning stability.

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