Philatelic supplies

This posting is on behalf of Dr. William Souder, University of
Alabama in Huntsville, souderw [at] email__uah__edu.

    The January, 1998 issue of American Philatelist has a very
    informative article on the use of plastics in philately.  A
    strong case is made for not using any PVC materials for storage
    of stamps because of the potential for acidic attack caused by
    hydrochloric acid which can be liberated by PVC.

    Most U.S. suppliers of plastic sheets for storing stamps use PVC
    materials.  Usually these materials are specified as containing
    no plasticizers (which certainly accelerate the contamination
    and degradation of the stamps), but they still have the
    potential for contributing to the acidic attack on the stamps.

    Although the use of Mylar or polypropylene is preferable to PVC,
    is there any quantified effect of storage in PVC? For the
    thousands of stamp collections already housed in PVC, can the
    cost of rehousing be justified by knowing the collection will
    last 20%, 70%, or 200% longer? How fast do materials degrade in
    these various materials?

    Also, are there suppliers of archival grade materials (non-PVC
    sleeves) for the philatelic market?

Jim Burd
Preservation Technologies, L.P.

                                  ***
                  Conservation DistList Instance 11:72
                Distributed: Tuesday, February 24, 1998
                       Message Id: cdl-11-72-027
                                  ***