John Myland Shellac M600. An un-diluted pure shellac varnish which may be mixed with Methylated Spirit up to 3 times to elongate its use and thin it to make application easier. One litre pot can make up to 4 litres of shellac, though some people prefer a thicker shellac or indeed a thinner one!

NEVER use on plaster when intending to mould with RTV Silicone, you will have an adverse reaction. Plaster generally reuires no selaing for use with RTV's. Shellacs tend to be used as bench sealers and run mould sealers where a plaster mould is use to make plaster castings.