Cellulose ethers

Re Tom Stone's study of the longevity of cellulose adhesives:  I
have heard previously of his findings on baskets that had been
repaired with methyl cellulose before and am still puzzled about it.
When I started using methyl cellulose (I hesitate to say how long
ago!) I tried it for different purposes and never could make it
stick two things together.  As a sort of sizing agent for powdery
pigments or powdery wood it was just wonderful, but the only
situation where I could ever use it for sticking thick paint or
pigment layers to a substrate was when the layer softened in water
and at least partly restuck itself.  In short, I am amazed that
anyone could make these repairs work even the first time.

I think it is vital to make it absolutely clear that what we might
call an adhesive failure is a matter of the material's appropriate
use.  This is the equivalent of what happens when conservators use
Acryloid B-72 as a moisture barrier.  The failure of this as a
tactic is not a failure of B-72 but a failure of the conservator to
understand its properties.

Under many circumstances I despise using aqueous emulsions, but for
basketry repairs with Tengujo tissue fibers, I often use very dilute
emulsion because it seems strong enough to last, even though as a
material it is not the best.  In addition, the ease of wetting and
subsequent removal of the repairs is aided by the presence of the
fibers, which somewhat mitigates what I find objectionable about
emulsions.  The bottom line is that a "better" material does not
create a "better" treatment if the material is not appropriate for
the particular use.

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                  Conservation DistList Instance 11:63
                 Distributed: Friday, January 23, 1998
                       Message Id: cdl-11-63-001
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