Place a drop of hot varnish into a glass of water, let cool for 5-10 seconds, pick up the varnish by touching it with your index finger, shake off excess water then pinch the varnish between your thumb and index fingers.

As you pull your fingers apart a string of varnish should form between the thumb and index finger.

Continue cooking until you are able to pull the string of varnish, using the string test (see above), without it separating as the fingers are spread apart 1.5 cm to 2 cm.

With soap varnishes also try to rub the drop of varnish in water to see if it dissolves. If it does, it is too alkaline, like soap, and you need to add more resin.

Category: Varnishing