Salopian the answer is there but the ingredients list does not explain the how and why. Now I dont want to find myself in the midst of some legal arguments over mixtures and ownership.
So!!!!!!
Mineral spirits well we all know what that is and can be purchased from paint stores and Art supply shops.
Varnish basically can be a mixture of a drying oil or another oil with a siccative added to encourage it to dry also the oil can be altered by removing its colour and of course smell. A resin is added to the oil now this resin can be a natural type of which there are many, or a manmade resin along the lines of an Alkyd types.
To make the whole mixture usable a spirit carrier is added to make the mixture workable, this will evaporate when the finish is applied because it has no further part to play.
Now by juggling the three constituents in various quantities you can make a product that can be applied with a brush that will dry slow so it loses the brush marks and at the other end one that will dry extremely fast and of course every stop between the two.
