The necessity often arises for a cheap oil for use in paint where rough work is to be protected, and the price of pure linseed oil would preclude its use. In such a case, substitutes are allowable. If, however, they are to be mixed with pure oil as adulterants to cheapen the product and defraud the purchaser, their use is to be deplored.

The ever-increasing demand for cheap paints has brought many substitutes for linseed oil on the market, few of which can compare in any particular with the qualities of the oil they are intended to replace.

The other vegetable drying oils are excluded on account of their price, (at one time cotton seed oil was used), and from it an excellent substitute can be produced. Animal and fish oils are also excluded for the same reason; price.

We have left then, to choose from, the various substitutes prepared from rosin, rosin oil and the mineral oils which, in most cases, need the addition of linseed oil to give them any degree of goodness.

The rosin and rosin oil substitutes are apt to dry extremely brittle and friable and the great difficulty with mineral oil, if combined in large proportion with linseed oil, is that the mineral oil, especially if of the heavier variety, will not dry, but, on the other hand sweat out on the layer of drying oil and be of no value.

When mineral oil is combined with linseed oil in moderate amount, it may be used as a fair paint oil.

The various resinates made by dissolving rosin in an alkali, forming rosin soap, and precipitating the rosin with some metallic salt, such as sulphate of zinc, sugar of lead, or chloride of manganese, produces metallic resinates which, when dissolved in benzine or turpentine form acceptable substitutes.

Rosin oil is refined, boiled and a proportion of manganese or lead dryer is added to give it more hardness and better drying qualities.

Oxidized linseed oil, which is oil boiled until it becomes a thick viscid substance, thinned with benzine or kerosene to a proper body is, perhaps, one of the best substitutes in use.

All these oils require apparatus and skill for their preparation.

To make substitutes without the aid of heat or apparatus, the following mixtures are recommended as being equal to, or the same as many of the so-called roof oils and cheap paint oils on the market.

Paint Oil From Rosin Oil

For this purpose use for light colored oils, first or second run rosin oil. The third run can be used for darker oils.

No. 1

Rosin oil, 30 gallons, Raw linseed oil, 15 gallons, Strong manganese dryer, 5 gallons. Mix thoroughly. Less linseed oil can be added, which reduces the quality of the resulting product.

No. 2

Rosin oil, 45 gallons, Strong manganese dryer, 5 gallons, The odor of rosin oil is often objectionable. Rosin oil is sometimes called bright varnish. It must be remembered that rosin oils and rosin, when mixed with white lead, have a tendency to liver, or thicken. Zinc white will act in the same way if the oils are not largely linseed. Such oils, at best, should only be used with the earth pigments, as ochre, iron oxides, graphite, etc.

Paint oil substitutes may be made also by substituting gloss oil, (rosin varnish) for rosin oil. In this way, the objectionable odor in rosin oil is eliminated as rosin varnish is free from it. Gloss oil, 30 gallons, Raw linseed oil, 15 gallons, Strong manganese dryer, 5 gallons, or, Glass oil, 40 gallons, Raw linseed oil, 10 gallons, Strong manganese dryer, 5 gallons. Liquid, or Japan dryer made with litharge or other lead compounds may be used in place of manganese dryer.

A dryer, containing both lead and manganese, is much more powerful than dryer composed of either of these substances alone. Oil of mirbane is used to disguise the odor of strong smelling oils.