Rosin Varnishes

by Louis DeGrazia

Originally published in Guild of American Luthiers Data Sheet #226, 1982 and Big Red Book of American Lutherie Volume One, 2000



Rosin varnishes are shunned by master violin makers because they are soft, “chippy,” and do not adhere well. Yet they are not so bad in these respects that they could not be used by an amateur or beginner on instruments with no pretension to outlast their maker. Pale rosin is a wonderful, natural, wood-derived resin that can be very easily made into a variety of beautiful and acoustically suitable varnishes both of the spirit and oil type. Its solubility in both alcohol and turpentine and its compatibility with oils and other resins make it a versatile ingredient that can help in combining normally incompatible substances to achieve special properties. Rosin varnishes have been around for centuries and in some respects they resemble those of the old Cremonese masters.

Pale rosin in powdered form can be obtained from pharmaceutical companies which use it in preparation of salves and ointments. This is the purest grade and is recommended for varnish making.

Rosin can be added to many varnishes to add body and to make them softer. Adding rosin to shellac makes a “woodcarver’s varnish” that can be prepared in just a few minutes, although it is best to let it stand overnight. This varnish brushes well, dries considerably slower than straight shellac, has good luster, and is much softer than shellac. To prepare, simply dissolve as much rosin as will go into solution in orange shellac and strain.