Q) Can Flexiglass and GRP products be interchanged, ie are Catalysts the same, and Flexiglass used as Topcoat for GRP? A Q) Can Flexiglass and GRP products be interchanged, ie are Catalysts the same, and Flexiglass used as Topcoat for GRP? A) No the two products are not interchangeable. Cromar2020-03-18T16:56:52+00:00 Share This Product. FacebookXWhatsAppEmail