Adhesive for wood

Hans Piena <h.piena [at] chello__nl> writes

>The GOC (Zutphen, Holland), together with the State History museum
>of Armenia are in the process of conserving a prehistoric wagon
>from Armenia dating around 1300 BC. ...
>...
>The majority of the parts nevertheless are soft, decomposed and
>soaked with glycerol which makes them difficult to glue back. Are
>there any glues which you would recommend to me?

A water resistant glue that should bond to a glycerol impregnated
substrate is a casein based composition.

Its recipe is as follows;

    Casein              10 gm.
    Calcium Hydroxide    2 gm.
    Water               40 gm.

The casein and calcium hydroxide are stirred in cold water and this
adhesive is then ready for use.

This glue has to be used immediately within 30 minutes of its
manufacture otherwise it will start to cure.

This is a fairly strong adhesive having a shear strength of 7.13
N/mm2 compared to PVAc having a shear strength of 8.82 N/mm2. These
tests were conducted with birch specimens in 55% RH. Animal glue was
also tested resulting in a shear strength of 4.05 N/mm2.

Further tests that we conducted with Casein Ca(OH)2 demonstrated
that it had a good modulus of elasticity being almost as good as
PVAc and better than Animal glue, again the specimens were birch.

Useful texts are;

    Dulac, Roger.  (1943)
    Industrial cold adhesives.
    London. Griffin & Co. Ltd.

    Braude, Felx.  (1943)
    Adhesives.
    Brooklyn. Chemical Publishing Co.

Prof. Jake Kaner
Buckinghamshire Chilterns University College
High Wycombe


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                  Conservation DistList Instance 15:25
                Distributed: Friday, September 21, 2001
                       Message Id: cdl-15-25-001
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