Re: linseed stand oil

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Re: linseed stand oil

In Reply to: linseed stand oil posted by DPetersen on 08/15/00 at 11:18 AM:

: What is the average drying time for LSO (linseed stand oil)? Is it weeks or months!?
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I'll answer that clearly and without the "hehe's"

Stand oil is NOT sun thickened oil. It bears absolutely no resemblance to partially polymerized oil because the molecules in Stand Oil have been rearranged into a very different substance that is not polymerized one bit (it is heated in an oxygen-free vacuum).

Those with difficulties in thinking complete thoughts assume that because both are thick that they are the same. They dry in very different ways and to different end results.

Sun-thickened and stand oil both dry at about the same rate...a thick layer will take between a week to ten days to dry. Then, as Derek said (hehe) there is a change in the structure (polymerization) which he assumes means that it turns to a plastic, like acrylic. What Derek fails to understand is that the word "plastic" in the English language means flexible, not the stuff they make Barbie dolls from.

As it ages, sun-thickened and other partially oxidized oils tend to grow brittle and darken considerably (boiled oils do not). Stand oil, on the other hand, dries to a more flexible film and does not darken appreciably in time. Stand oil will wrinkle if applied in a thick film. The preferred method is to thin it with turpentine or Oil of Spike. That insures that it will not wrinkle, it will dry quicker (about two days) and will darken even less than full-bodied Stand Oil.

Both oils have good binding qualities but poor adhesive qualities, thus they dry to slippery surfaces that repel subsequent layers of oil. The best way to avoid that problem is to mix a small amount of an adhesive resin into the medium. The best for that purpose are the balsams. Certainly one of the nicest mediums to paint with is made with Stand Oil, Canada Balsam and Oil of Spike or Turpentine. It dries overnight and readily accepts subsequent coats of paint without separating into bubbles and blisters.