and there's this info

sidbledsoe. . . a drying oil refers to an oil like linseed that oxidizes or absorbs oxygen and then polymerizes to form a solid state matrix rather than a liquid like it is before oxidation. Non drying oils do not have the long chain fatty acid molecules with carbon double bonds that allow this process to proceed. There is no absorption of water, in fact the opposite is true. Water is a polar molecule, oils are non-polar. they do not mix or absorb due to that physical property.

smokin
. . . The difference between a dry oil and non drying oils are percentages of fatty acids. The 3 main types of Fatty acids are Linoleic, Linolenic, and Oleic acid. If the percentage of monounsaturated fatty acids (Oleic) is too high, then the oil will never dry because this type of fatty acid does not produce those chains to create a film. The store bough safflower, Olive oil, and many other types of Veggie oils are very high in monounsaturated fatty acids, thats why these oils wont ever dry, . . .

Linseed oil is about 19% Oleic , 24%Linoleic, 47% Linolenic for every brush stroke. Olive oil is about 65% Oleic Acid. If I clean my brush in olive oil or safflower oil, the trace bits of oil left on the brush will not alter the paint on my pallet in any signifcant way. If the paint on my pallet increased by even 0.5% in oleic acid I would be surprised.

. . . It is best to get oils with no vitamin E or any anti oxidents if possible. I would opt for safflow, poppy, flaxseed, or walnut since these are the types of oils used for making paints.

I have safflower oil with vitamin E . . . the trace amounts of oil left on the brush after I used to for washing only (not used as a medium whatsoever), has NO effect on drying times whatsoever.

(https://www.wetcanvas.com/forums/showthread.php?t=514015)

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