Joha Oil Varnish by Hammerl, 2 oz bottle. JOHA ® Oil Varnish Standard. This varnish contains a mixture of natural and synthetic resins, dissolved in turpentine and linseed oil. This varnish has very good vibration properties and a hard-wearing surface. For an oil varnish, it dries very quickly . Each painting approx. 1-6 days. We recommend approximately 4-6 ounces for a complete violin/viola.