Emulsion bound (EB) CSM (Chopped strand mat) is held together with an emulsion which dissolves in styrene (a special thinner). Polyester resin systems have an excess of styrene, which dissolves this binder.
Emulsion bound CSM, will start to dissolve and fall apart, when ‘wetted out’ with polyester resin. Emulsion Bound CSM should never be used with epoxy systems, NEVER! – Use a friendly powder bound material instead 🙂
Fact: Epoxy systems do not contain styrene.