P38 polyester filler is a two component chemical paste used for the filling of holes & imperfections in surfaces such as steel & GRP. It has been specially formulated for the professional user & combines good filling & smooth spreading properties together with ease of sanding. Can be used on the following surfaces bare steel degrease & abrade with P80 paper original paint surfaces (with the exception of thermoplastic acrylics) degrease & abrade with P180 grit paper & GRP degrease & abrade with P80 grit paper. Can be over-painted with most paint systems including 2K ideally a full system is recommended including primer.