Glue Sticks

Is it safe to use the new UHU purple glue-sticks for tipping in pages in
books?  I.e. is this stuff acidic, neutral, or what?  I was told in my
preservation class that the earlier, white UHU was safe, but one of my
co-workers claims that it is acidic.  Does anyone know for sure?

    **** Moderator's comments:   This subject has been discussed a bit
    before. Those interested should request the files by sending a
    one-line request (send YEAR5-3.DST YEAR4-2.DST) to
    consdist-request [at] lindy__stanford__edu)

    All of the glue sticks I have seen have had very high pH's, too high
    for safe use on paper. There are several problems with using these
    things: anytime there is a difference between the pH of the paper
    and that of the adhesive, the paper can be expected to age
    differently where the adhesive is, making either a lighter or darker
    area.  Second there is some paper deterioration associated with
    highly alkaline situations. Third, they don't work all that well.
    I've seen them bleed and dry out even in just a few months (other
    people report just the opposite, however).

    Even if you get reports from people saying "I've been using them for
    10 years and haven't seen any problems", these still don't qualify
    for use in any situation where you are concerned about the
    preservation of artifacts (e.g. archives and special collections)
    because (a) most people won't recognize damage when they see it (b)
    "damage" isn't always visible (c) the way much deterioration of
    organic materials happens is that there is a *long* period where
    nothing seems to be happening (called the induction stage) followed
    by a period of more rapid change.  During the induction stage, the
    system is indeed moving inexorably to a state where deterioration
    becomes obvious.  It's sort of like smoking:  you can smoke for
    years and nothing bad seems to happen (fooling you into thinking
    that cigarettes must be ok), then the effects start accelerating,
    then you die.

Jeff Curtis

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                  Conservation DistList Instance 6:25
                Distributed: Saturday, October 31, 1992
                        Message Id: cdl-6-25-008
                                  ***