Dammar and mastic varnishes: hardness, brittleness, and change in weight upon drying

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Publication Type:

Journal Article

Authors:

Feller, R.L.;

Source:

Studies in conservation, Volume 3, Number 4, p.162-174 (1958)

Keywords:

America, damar, dammar, films, mastic, mastics, North America, properties, resins, thin, USA, varnish

Abstract:

Films of dammar and mastic resins, laid down from spirit varnishes and well-dried, were found to be similar in brittleness and rocker hardness, and much more brittle than samples of polyvinyl acetate and poly-n-butyl methacrylate. After one month of drying, mastic varnishes were harder and more brittle than dammar; this initial difference apparently becomes less in time. It was also demonstrated that the addition of 5% stand oil by volume to a 35% solution of dammar varnish did not markedly affect the brittleness observed after 6 months. Evidence was obtained that spirit varnishes formulated with these resins retained appreciable solvent at the end of 1 month of drying, and that oxidation occurred during the drying of varnishes formulated in turpentine.