Shunyata Posted August 3, 2022 Report Share Posted August 3, 2022 I am planning a first shot attempt at colophon varnish. Does this seem like a reasonable recipe? (from Peter Grankulla web page) Colophony 140g, cooked down to 75g Boiled linseed oil 75g Gum mastic 15g Turpentine 45g Colophony cooked for 15+ hours at 150 - 180 C The temperature is gradually raised to keep the same viscosity Weight reduction 46.5% Lots of stirring!! especially in the first hour when it fumes a lot Linseed oil heated to the same temperature and slowly stirred into the colophony Cooked for 50 min together with the colophony Reducing temperature to ~100 C Mastic drops added slowly while stirring Cooked for another 15 min at lower temperature to 90 - 100 C until the varnish is very calm Balsam turpentine heated to simmer Slowly stirred into the varnish and cooked 5 - 10 min until calm again Filtered and decanted into a glass jar. Quote Link to comment Share on other sites More sharing options...
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