Adhesives for glass

We are currently doing some research for the conservation of a large
contemporary 'stained glass window'.

The window is made of large clear glass panes on which smaller
pieces of colored glass have been glued with epoxy (flat side to
flat side). Some of the colored glass is simple flat sheet but some
are fairly heavy glass 'blocks' that are hand-cut. The adhesive is
starting to fail in some areas and we will need to re-adhere some of
the pieces. Some of the issues of this treatment include:

    The window can only be treated on site, that is vertically, and
    we only have a couple of days for the treatment (while the
    thermos glass on both side get replaced). For this reason we
    eliminated using adhesives that take a long time to polymerize
    such as Hxtal.

    The window is situated in the subway, where there is a lot of
    vibration. This situation eliminates the possibility of using a
    very hard, brittle adhesive. For this reason we had to put aside
    using UV cure adhesives.

Right now we are considering using 3MTM VHBTM no. 4910 (double sided
tape), either on its own, or as a way to hold the glass pieces in
place and use a fluid silicone sealant on the edge between the
pieces and the clear glass panes. We'll be doing tests shortly to
assess the visual impact of both these techniques as well as the
bond strength.

We would like to hear from conservators having treated similar types
of objects, used the 3M tape for treatments to good or bad results,
or who may otherwise have ideas for alternative treatments.

Isabelle Cloutier
Restauratrice de sculptures
Centre de conservation du Quebec
1825 rue Semple
Quebec (Quebec) G1N 4B7
418-643-7001 ext 281
Fax: 418-646-5419


                                  ***
                  Conservation DistList Instance 23:44
                    Distributed: Sunday, May 9, 2010
                       Message Id: cdl-23-44-011
                                  ***