Base Coat is generally a chemical set, plaster-based cement, used to bond paper tape with a plasterboard lining substrate by hand or machine tools. After the first coat has set a second base coat can be applied, and once dry a Top Coat or All Purpose Lightweight can be applied as a finish coat. GTEK Base Coat is available with a working time of 45 or 60 minutes, we also stock sandable base coats with a 5 and 20minute set time when a fast turnaround time is needed on small jobs.