Gyprock Jointmaster™ Gyprock Jointmaster is a heavyweight topping compound used as a top coat in a three coat plasterboard jointing system. Jointmaster is a low VOC, pre-mixed compound, manufactured by Gyprock in Australia to stringent product specifications and is packed in a blue coloured bucket. Application: Hand Tools Allow adequate time for the previous coats of joint cement to harden before applying a finishing coat. 1.Apply a thin finishing coat of Jointmaster wide enough to conceal the previously coated joint. Soften the outer edges of the newly trowelled compound with a damp brush before feathering the edges with a trowel. 2.Cover previously coated fastener heads, overlapping about 25mm. Machine Tools Apply a thin finishing coat of Jointmaster using a 250mm or 300mm finishing box. Sanding Allow compound to dry for at least 24 hours, then sand to a smooth finish using 180 grit sandpaper or 180-220 grit sanding mesh.
