this type of repair. Water-based emulsion glues can be added to existing
hide glues, as they will bond reasonably well. However, adding a glue such
asPVA emulsion, with different mechanical properties that would make it
react differently to environmental changes, can lead to failure of the glue
line. This consequence, as well as concern over the long-term stability of
PVA emulsion, discourages its use in wood conservation.
There is growing interest in synthetic hot-melt adhesives for this
type of treatment. Although further investigation of hot-melt adhesives is
needed, there is no theoretical reason why this treatment option should
not be developed.Replacing failed adhesives
The option of completely removing the aged adhesive materials is avail-
able, but it should be undertaken only in cases in which the object can be
completely disassembled and the conservator has access to all gluing sur-
faces. For panel paintings, this treatment would be limited to backing sup-
ports. There is frequently a need to remove all of the existing glue because
of the number of factors that contribute to adhesive failure, from environ-
mental fluctuations to inept previous repairs with inappropriate adhesives.
The continued presence of a failed glue on an object contributes to its
accelerated deterioration.
Any adhesive material that can easily be removed mechanically
with a tool without damage to the substrate is treated first. Ifmechanical
removal cannot be done easily and cleanly, solvents are added to the proce-
dure. The adhesive will swell and/or soften so it can be removed with
wooden scrapers or cotton swabs.The nature of the adhesive materials used on artifacts often reveals vital
information about their historical/material technology that can provide
useful clues and direction to the caretakers of the objects. The wise con-
servator will base conservation treatments requiring adhesive processes on
a sound understanding of these processes.1 Most sources discussing the technology of natural resins refer to their widespread utility as
coatings, sealants, and adhesives. See Koob 1984 and Mantell 1942.Cummins, Jim
1986 Visit to a glue factory. Fine Woodworking(March/April):66–69.DeBeaukelaer, F. L., et al.
1930 Standard methods (revised) for determining viscosity and jelly strength of glue.
Industrial and Engineering Chemistry 2(15 July):348–51.Feller, Robert L., and David B. Encke
1982 Stages in deterioration: The examples of rubber cement and transparent mending tape.
In Science and Technology in the Service of Conservation: Preprints of the Contributions to the
Washington Congress, 3–9 September 1982,ed. N.S.Brommelle and Garry Thomson, 19–23.
London: International Institute for the Conservation of Historic and Artistic Works.Fernbach, R. Livingston
1907 Glues and Gelatine: A Practical Treatise on the Methods of Testing and Use. New York:
D.Van Nostrand.References
Note
Conclusion
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