5ltr Shellac Pale Sealer can be used as pure shellac varnish in sealing plaster moulds. The benefit over shellac varnish is that shellac sealer can be used on damp plaster and gives a long lasting coating . Ideally use the sealer neat, and give 2-3 coats letting each layer dry before applying the next. Do not use with Silicone rubbers. Can be diluted with meths if needed.