Dear Debra, Are tung oil and linseed oil safe as wood furniture finishes? Pacific Rim uses a blend of tung oil, linseed oil, and Varathane in their furniture.
Tung Oil comes from cold pressing of the seeds or nuts of the Tung tree. Tung trees mainly grow in the mountainous regions of China. The oil has been prized for centuries for it's qualities as a wood finish. Tung oil penetrates deeply into wood, enhancing the character of the wood while creating a beautiful water-resistant finish. The ancient Chinese used tung oil to waterproof ships.
These qualities make tung oil perfect for wood bowls, counter tops, outdoor furniture, decks, wood siding, wood flooring, concrete, brick and just about any porous surface that needs a nontoxic waterproof protection.
When choosing a tung oil, it's important to select one that has no additives or distillates. Tung oil labeled "pure" should be just that. Check the MSDS to see if there are any additional ingredient. One tung oil product I checked had 73.77% Stoddard Solvent (aka petroleum distillates), plus Trimethylbenzene, Ethylbenzene, and Cobalt Naphthenate, all very toxic VOCs.
Because the source of tung oil is a nut, people with nut allergies should avoid contact with (or even the odour of) tung oil. Otherwise, pure tung oil is a safe and natural finish.
Linseed oil is obtained from the dried ripe seeds of the flax plant, which is also used to make linen fabric. The oil is obtained by cold pressing, sometimes followed by solvent extraction.
Linseed oil has "polymer-forming properties, which means the molecules have characteristics similar to plastics. Linseed oil is used on its own or blended with other oils, resins, and solvents to make wood finish, to bind pigments in oil paints, as a plasticizer and hardener in putty and in the manufacture of linoleum.
When used as a wood finish, linseed oil dries slowly and shrinks little upon hardening. Like tung oil, linseed oil soaks into the pores of wood, leaving a shiny but not glossy surface that shows off the grain of the wood.
Again like tung oil, linseed oil is sold "raw" or with chemicals added. Linseed oil labeled "boiled" has added mineral spirits (petroleum distillates), turpentine, and other additives that help it dry faster. It takes months for raw linseed oil to harden.
Varathane is a liquid form of polyurethane. The problem with polyurethane is in the additives and solvents. When these have completely cured, the polyurethane finish is inert. I'm sitting at a desk at this very moment that has a water-based varathane finish. It gives a harder finish to the wood, with more protection against scratches.
The combination of tung oil, linseed oil, and varathane is a good one.
As for the Pacific Rim finish, it is "a nontoxic finish that is completely inert after dried." Pacific Rim has been around for a long time and I have never heard a complaint about their finish. You can also order their furniture unfinished and apply the finish of your choice.
I agree that the Pacific Rim finish would be inert when completely dried.
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