Special non-asbestos filler in powder form for addition to the resin mix after the initial mixing has taken place. The resultant sealer filler mix has two very useful properties. The mix is very thixotropic and can therefore be applied to vertical areas. The mix can be applied to operate at temperatures up to 180°C (356°F). When it is applied a pre-coat, prior to carrying out a repair, it will help to insulate the resin laminate from the operating temperature of the parent body repair.