How to make Varnish
100 g resin (crushed)
150 ml linseed oil
250 ml turpentine
Cook resin in Linseed oil until it produces at least 1/8" string when dropped on glass.
Mixture darkens with time!
Mix in turpentine after mixture cools to about 1200 °C (error?) - must not be boiling.
Sieve through fine mesh into small dark bottles.
Use fine shirt material for sieve.
Resin can be from Spruce, Pine, etc.
Amber can be used, but it must be fused first. Melt carefully, allow to cool then crush.
Resin may be purchased or gathered from softwood trees.