I had the pleasure of assisting on the installation of all the process
equipment at Henkel Adhesives in Elgin, Illinois, in the early 1990's
when they started the production of self-curing, self-foaming, urethane
adhesive (Gorilla Glue).  At that time the largest user was the
manufactured home and travel trailer industry.

The entire process of manufacture takes place in a dry nitrogen
atmosphere.  There were a number of dessicators and other dryers in all
the air and chemical piping and they back flushed everything with dried
nitrogen before packaging.

The resin compound is designed to use moisture from the air to start
the curing reaction.  If the joint is not clamped tightly, the adhesive
foams to fill the space and the foam is relatively weak.  Where clamped
tight, the resin bead stays solid and is very strong.

Like most urethane based adhesives, once cured, it is next impossible
to dissolve in any common solvents.

Bill Klinger
Los Angeles, California, USA