Book with wooden boards

Cyril Formby <formbys [at] tiscali__co__uk> writes

>I am currently working on a 14th century lectionary, of which a
>quarter of the front board has been lost due to decay and woodworm.
>I would appreciate any advice on the best way to repair the board to
>enable the new leather thongs to be laced onto the boards.  The
>leather is still sound.

There are several options, depending on the thickness of the board,
type of wood, and other structural aspects. It's not clear from the
query whether the spine is covered, and if that will provide
additional hinge support. If the board is not too thin to peg, one
traditional method would be to find a well-cured board of the same
type of wood, with similar grain, and align the replacement piece so
the grain is running the same way as the original. Adjust the
moisture content so both the old and new wood match, to minimize
hygroscopic effects when the humidity changes. Cut the original to
the point where the wood is solid. Trace the cut edge and make a
template for the replacement part. Drill both parts with aligned
pegholes, glue, peg and clamp.

Another method would be to leave the existing decayed board edge as
is and fill the wood with a stable resin. Trace the rough edge, make
a template and prepare the new wood so it fits as closely as
possible with minimal gaps. Apply the resin to the meeting edge of
the new wood. Mix cotton fibers or other filler (microballoons, etc,
or whatever is appropriate to the size of the gaps) with the same
resin. Align the parts and hold in place with either light clamp
pressure, or simply frame them in at the edges of the boards so they
don't slip. Fill the gaps with the resin/filler mixture.  If
necessary, sand the resin to the board surface after curing, or add
additional filler if there is a recess.  The advantage of this
method is that it preserves the history of the decayed edge, which
is a different aesthetic position. It also is reversible to the
other method, if in the future either the aesthetic decision
changes, or the resin proves unstable, etc., simply by cutting off
the resin impregnated part.

For ten years I repaired my 1956 Chris Craft Constellation that way,
using West System epoxy. During Hurricane Bob, the storm surge
raised the boat so the hull banged against the piling for hours. It
was at an area I had saturated with this resin, that had been so
spongy you could put your finger through it. The only damage to that
area was that the paint was scraped off. My understanding is that
boats constructed by the Gougeon brothers over 30 years ago using
West System epoxy are still in excellent condition, despite exposure
to marine conditions. The caveat is that the epoxy is sensitive to
ultraviolet light, and exposed areas need to be painted or coated
with UV filter. I believe some work has been done mixing UV filter
material into the epoxy. If you use this method on a book cover, you
might want to mix pigment in the resin or paint the exposed resin to
match the board color.

Richard


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                  Conservation DistList Instance 18:51
                  Distributed: Tuesday, April 26, 2005
                       Message Id: cdl-18-51-007
                                  ***