The David's ISOPON P40 Glass Fibre Repair Paste is a two component chemical paste used for the bridging of holes in rust in surfaces such as steel and GRP. It forms a very hard durable surface and can be sanded and shaped if required and it is suitable for use on the following surfaces; bare steel (degrease and abrade with P80 paper), original paint surfaces (with the exception of thermoplastic acrylics - degrease and abrade with P180 paper) and GRP (degrease and abrade with P80 paper). Two component chemical paste used for the bridging of holes in rust Strong polyester bridging compound Ideal for bridging holes and is water resistant when cured Sandable after 20 minutes (at 20C) Can be over-painted with most paint systems including 2K