Fiberglass sculpture

Barbara Appelbaum <aandh<-at->mindspring<.>com> writes

>I am working on a resin/fiberglass sculpture.  The basic structure
>is two hollow spheres, each about 1-2 feet long, that were attached
>at an area about two inches in diameter.  It broke at the neck,
>leaving only small areas of contact where an adhesive could go.  In
>order to make the repair strong, we have been thinking about filling
>one of the spheres so that we could establish something solid to use
>to increase the area of adhesive contact.  Does anyone know of an
>injectable foam with decent aging properties?

In the late 1970's I filled a weak, collapsing, opaque half sphere
with common polyurethane foam. Approximately ten years later I
inspected it and the foam showed absolutely no deterioration.
Possibly, out of light, polyurethane foams commonly used for wall
insulation and boat floatation (such as Tiger Foam) will endure.
They typically weigh 2-4 pounds per cubic foot. But they do not
present good new bonding surfaces. Only expanding epoxy will bond
very well to FRP and provide a bonding surface.

However, at typically 20 pounds per cubic foot, expanding foam epoxy
is likely to be too heavy for your application as a core fill.
Perhaps you can allow a limited amount of the foaming epoxy to open
expand at the orifice where you want a bonding surface. It will
strongly bond to the inner FRP surfaces. Else, try to expand an air
balloon inside to hold an empty space. Foaming epoxy seems to be
your best material for longevity, excellent bonding to the FRP and
creating a new bonding surface.

Robert Lodge


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                  Conservation DistList Instance 27:18
                Distributed: Thursday, October 24, 2013
                       Message Id: cdl-27-18-001
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