Rosin Oils are produced by distilling rosin.

Large cast iron stills are used for this purpose and a fair grade of rosin gives the best results. The addition of 5 per cent. of paraffine oil to the rosin to be treated will ensure lighter and better products and increase the yield of lightest colored oil.

The products of distillation are, first, resin spirit (pinolin) which can be used as a solvent. It closely approaches turpentine in its general characteristics save that the resinous or slightly tarry odor is present unless it has further treatment to deoderize it. It is sometimes used in place of turpentine and is somewhat cheaper.

Second, pale rosin oil, or so-called first run, a light colored oil, of bluish cast and moderate body.

Third, blue rosin oil, or so-called second run, rather dark and heavy.

Fourth, green rosin oil, or so-called third run.

Fifth, the residue, which is a more or less solid pitch, suitable for iron varnish, shoemakers' pitch and like purposes.

Pale, or first run rosin oil is most suitable for refining. This is done by boiling it with direct steam, washing with hot water and treatment with soda lye and further boiling and washing.

The oil is bleached and further deoderized by heating it with indirect steam and passing a current of warm air through it by means of a blower.

The resulting product is an oil free from resins and acid, and will dry without cracking or stickiness. It is, therefore, suitable as a paint oil and in the manufacture of varnishes and lacquers.

Refined rosin oil is also used in printers' ink, lubricating oil and in the manufacture of preservatives, soap and medicinal preparations.