A method of producing an integral self supporting coating test piece from particulate material including the steps of (i) producing a reusable mould having a depression which conforms to the desired shape and volume of said coating test piece, the reusable mould including silicone rubber, (ii) roughening the surface of the reusable mould, (iii) heat treating the reusable mould, (iv) thermally spraying particulate material into the depression in the reusable, mould, and (v) removing the reusable mould from the solidified coating test piece.