I've always wondered about a few things...
- when working with polyester fiberglass layups, why do you lay 3/4
oz. fiberglass mat underneath the fiberglass cloth? I've read that
the mat is more waterproof than the cloth. The mat is supposed to
offer better adhesion than the cloth. I suppose that this would be
like putting a primer coat before a paint job. One company recommends
that you use mat between each layer of cloth for better adhesion.
Also, never use epoxy with mat, it isn't supposed to work very well.
- another question that keeps popping up, is about using acetone as a
thinner for polyester precoats on urethane foam panels? Several
companies are recommending that the polyester resin should be thinned
out with 10% acetone to provide a precoat for urethane foam
construction. It is said to be like billions of little nails into the
foam, so that the mat overlay has an excellent surface to stick to
without any delamination.
- I've also wondered about using hot melt glue sticks to join two
pieces of urethane foam? I am considering to use 'Gorilla Glue' which
has been recommended by the manufacturer of the urethane foam panels.
The construction time will take much longer but I believe that the
panel joint will be much stronger. The 'Gorilla Glue' is a urethane
based adhesive, so this makes sense to me.
