Using soybean oil in custom mixed wiping oil/varnish

[Roger Lueck]

There is a myriad of discussions regarding creating a “custom mixed” wiping oil/varnish.

Alkyd, phenolic and urethane resin based varnishes are dissected extensively as a integral ingredient.

The reducers discussed are Mineral Spirits, Turpentine and Paint Thinner as a second constituent of the mixture.

Usually Tung Oil or BLO is included as a third part of the mixture. While unlike Tung Oil and BLO, soybean oil is not a “drying oil”, linseed oil is not a drying oil either in it’s raw state. Soybean oil has qualities such as light in color and inexpensive that would seem to be desirable. Several manufacturers use soybean oil in their varnishes in lieu of Tung Oil and BLO.

Why is soybean oil not used more as the third part of a custom mixed wiping oil/varnish? Is it because there is not a readily available modified soybean oil that will dry in a reasonable amount of time?

Thank You,
Roger

[Scott Holmes]

I'm pretty sure you answered your own question. Raw linseed oil is not normally used in an oil/varnish blend either; it's usually "boiled" linseed oil (BLO). (not really boiled, that would ruin it, it has metal driers add to speed the curing process.

[Roger Lueck]

The process of using metallic driers to transform raw linseed oil into BLO is fairly well known. I had hoped there would be someone with experience using metallic driers such as Japan Drier with Soybean Oil. How does Japan Drier work with soybean oil in regard to the drying/curing characteristics and the amount of time required?

Soybean Oil would provide a less expensive finish than if Tung Oil were used and a lighter colored finish than if BLO were used to create a wiping oil/varnish.

Roger

[Brett Luna]

I'm largely ignorant of the chemistry involved in metallic driers but I would be concerned about rancidity using raw soybean oil. This Wikipedia article (https://en.wikipedia.org/wiki/Linseed_oil#Modified_linseed_oils) mentions that soybean oil can be treated similarly to linseed oil but takes longer.

ETA: I've also read elsewhere that rancidity can be accompanied by a change in color...darker, I presume.

[Howard Acheson]

>>>> Is it because there is not a readily available modified soybean oil that will dry in a reasonable amount of time?

Yes. The only way it will dry is to add some metallic driers to the mixture. Metallic driers are poisonous and should only be used by folks who know what they are doing.

What's wrong with using linseed oil or tung oil. BTW, raw linseed oil is made into a drying oil by the addition chemical driers.

[Roger Lueck]

There is nothing "wrong" with Tung Oil or BLO. The intent of my post was to determine if there was a modified soybean oil that could be used in a "custom mixed wiping oil/varnish" in lieu of Tung Oil or BLO that would dry in a reasonable amount of time. I'm not concerned about soybean oil becoming rancid as vegetable oils typically have a 1 year shelf life, however, how the oil was stored after hexane extraction will have an affect on it's total shelf life before turning rancid.

The reasons for the inquiry into using soybean oil is a wiping oil/varnish finish using soybean oil would be much lighter in color than a wiping oil/varnish finish using BLO. Additionally, a wiping oil/varnish finish using soybean oil could potentially be more cost effective than a finish using Tung Oil.