Description: SPARX SF – 21 is speciality low viscosity two component epoxy primer product based on epoxy (resin) and reactor (hardener) to be used with self smoothing epoxy and PU scratch coat for binding with floor system or other cementitious subtracts where surfaces very porous, it requires more than one coat of primer to achieve the desired bonding of efficiency. If the substrates are particularly smooth the surface of the SPARX SF – 21 should be seeded with fine aggregate immediately after application of the primer to give a mechanical key to facilitate installation of resin screeds and topping.