Plexiglass

 

Plexiglass/fiberglass question

Q.  I was reading your article on painting to insure permanence (100+ years) Applying paint on canvas or hardboard. I am considering painting on plastic or Plexiglas/fiberglass. How long will it last? Acrylic? Oil?

 

A.  It is hard to say.  These materials are designed for commercial/industrial use and are not made with permanence in mind.  Plexiglas does break down, yellow and become more brittle with age, I am not sure about fiberglass.  The strong epoxy glues used to make fiberglass may break down in time.  The other concern is the permanent adhesion of the paint to the surface.  Plexiglas is fairly inert but paint (oil or acrylic) will not adhere well to it unless it is treated to give it more 'tooth', sanded or etched with a sand blaster for example.  Fiberglass is more porous than Plexiglas as a rule but I am not sure I would want my paint coming in direct contact with it (because of the unstable nature of the epoxy mentioned above).  You might consider some isolating varnish that would adhere well to the fiberglass before painting on it.  The Golden paint company makes a medium that is designed specifically for this purpose, it is their GAC 200 medium.