Water damaged books

Garry Harrison <gaharris [at] indiana__edu> writes

>The usual mixture of PVA and methyl cellulose we use for repair
>treatments was further diluted with water. I didn't measure the
>proportions by volume, but just diluted it until the syringe would
>push it pretty effortlessly. Just guessing, I'd say the amount of
>water added was maybe 1/8 the volume of the mixture. ...

This reference to "the usual mixture of PVA and methyl cellulose"
interested me. I have not heard of this combination being used
before.  As an objects/ethnographic conservator I would be
interested in hearing more about this in case it has other
applications.

What proportions are "usual"?  What qualities does this mixture
afford that cannot be obtained by the pure adhesives alone?  Does it
really make a good bond or could there be polymerization problems
due to the two very different materials in an admixture?  What is
the effect on the aging properties of each?  What does the hardened
product look like?  I could possibly guess some of the answers to
these questions, but I would rather hear from those that have
experience with it.

    **** Moderator's comments: This is fairly common among book
    conservators and binders. By PVA here, we're talking about
    emulsions, typically (often vinyl acetate-ethylene copolymer
    emulsions), and the methyl cellulose is added to modify working
    properties. Searches through CoOL and through the DistList
    archives will give you some background. Also I think (I don't
    have a copy handy so I can't check) that the Paper Conservation
    Catalog (a Book and Paper Group publication, available from AIC
    <URL:http://aic.stanford.edu>, chapter on Adhesives may have
    some info on this topic.

Linda S. Roundhill
Art and Antiquities Conservation
Woodinville, WA
USA
425-481-0720


                                  ***
                  Conservation DistList Instance 15:76
                   Distributed: Friday, May 10, 2002
                       Message Id: cdl-15-76-008
                                  ***