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Learn about mineral oil, tung oil, how they are similar, and what the important differences are between the two. Then, find out the major differentiating factor, when to use each type of oil, and which is better.
Contents
What Is Mineral Oil?
Mineral oil is any oil that originates from a non-vegetable source, usually as a byproduct of petroleum processing.
Mineral Oil Characteristics
Mineral oils are:
- Clear
- Odorless
- Non-drying
- Inedible unless purified
- Non-conducive
- Non-compressible
- Highly-flammable and combustible
- Slow to biodegrade.
Mineral Oil Uses
Mineral oils have both consumer and industrial applications.
In the home, processed mineral oil with fragrance added is used to protect the skin of infants. This formulation is usually sold as ‘baby oil’. It can be ingested by adults, cats, dogs, and livestocks and has a mild laxative effect. It can be used internally as a safe way to increase vaginal lubrication.
Mineral oil is an ingredient in many cosmetics, such as lotions or creams used on the face. It releases material on the skin without clogging pores, which makes it an excellent choice for removing makeup. Most cold creams contain mineral oil. Mineral oil will remove temporary tattoos.
While mineral oil isn’t used to cook with, it can be used as an industrial food glaze. Mineral oil glazes keep gummy candies from sticking to each other. In the European Union, this use is not allowed.
Gardeners and poultry raisers know mineral oil as an effective mite deterrent. Mineral oil applied to the feet of a chicken will suffocate scaly mites. Mineral oil mixed with a detergent will do the same thing for mites on houseplants.
It can also be used to gently clean alabaster, and to condition wood.
In scientific environments, mineral oil is used as a non-conductive medium for the culture of embryos and oocytes. By creating a film on top of the culture, the mineral oil insulates the specimens from temperature changes, increasing the chances of viability. Super-pure formulations have been used to conduct particle physics experimentation.
In industry, the most common use for mineral oil is as an insulator for electrical transformers, and it is sometimes called ‘transformer oil.’ It can be used as a hydraulic fluid due to it’s non-compressibility.
When technicians are trying to find leaks in closed environments, they use special machines to heat up mineral oil and produce a thick white cloud of smoke. After filling the closed environment with this smoke, they observe where, when, and whether it emerges. Auto emissions tests are conducted in this way.
Performers who work with fire may choose mineral oil as fuel.
What Is Tung Oil
Tung oil is a naturally occuring substance present in the seeds of the tung tree.
Tung Oil Characteristics
Tung oil is:
- Transparent
- Strong-smelling
- Yellowish
- Slow to dry
- Naturally antimicrobial
- Highly flammable and combustible
Tung Oil Uses
Tung oil is used to protect wood. It is a penetrating oil finish, in contrast with film-forming finishes such as shellac, lacquer, polyurethane, and other varnishes.
Penetrating oils soak into the pores of wood, also known as the grain. They adhere to the surface of the wood as well as the cellular structure inside. Rather than a protective coating that sits on top of the wood, tung oil seeps below the surface and forms a barrier there.
Wood treated with a penetrating oil finish will be less resistant to damage from impact, scrapes, and scratches.
Unique among penetrating oil wood finishes, tung oil confers natural resistance to pests and fungi. It also helps wood resist moisture damage. Because the barrier formed is flexible and somewhat elastic, tung-oiled wood is able to expand and contract with changes in temperature or humidity.
A flexible, water-repelling, mildew-protecting finish like tung oil is ideal for use on exterior wood. Furniture and trim are the best candidates for tung oil finish. Decking can be coated in tung oil, but it will show damage much more quickly than a more durable finish.
Tung oil is often modified with drying agents to speed the extraordinarily long dry time. At least three days is necessary for tung oil to dry in ideal conditions. In extremely hot weather, cold weather, or high humidity, it can take weeks to months.
Tung oil has a strong odor that does not dissipate quickly. It will not yellow with age and never goes rancid, unlike most other vegetable oils.
Drying oils (such as tung oil) harden in two phases. In the first phase, the moisture evaporates. As it is exposed to air, a phenomenon called crosslinking occurs, binding the molecules more tightly together.
Due to this, tung oil shrinks slightly as it cures, a process that takes about one month in ideal conditions. Other drying oils include; walnut, poppy, and linseed oil.
Tung oil can also be easily confused with danish oil, but there are differences.
Dense, fine-grained wood such as rosewood or mahogany is often treated with tung oil. Pure tongue oil lends a honey-colored sheen to light-colored wood. Dark tung oil has a darkening agent that diminishes the brightness of wood.
Tung oil releases heat as it dries. Rags are used to apply tung oil to clean, dry wood. When soaked rads are wadded in a closed container, the heat has no method of dissipation. When the heat builds to the flash point of the rags, spontaneous combustion can occur.
Hanging soaked rags on a clothesline or draping them over sawhorses to dry before disposal is an excellent method for preventing spontaneous combustion.
Tung oil is often modified with drying agents to speed the dry time. Un-modified or pure tung oil takes about three days to dry to the touch.
Mineral Oil vs Tung Oil
The similarities between mineral oil include their viscosity and their applicability to wood. The differences are wide ranging. The color, odor, and digestibility of these two substances are all very different. One dries to form an impenetrable barrier while the other is non-drying. Both are flammable.
Similarities
- Both mineral oil and tung oil can be applied to wood.
- Both mineral oil and tung oil are oily liquids.
Differences
- Tung oil has a strong odor, while mineral oil is odorless.
- Mineral oil is clear. Tung oil is slightly yellow. Dark tung oil is yellowish-brown.
- Mineral oil can be ingested as long as it is properly purified. Tung oil is not recommended for consumption.
- Given sufficient time, tung oil will eventually harden into a flexible barrier. Mineral oil does not have this capability.
- Tung oil carries a risk of spontaneous combustion when soaked rags are stored in a compact area. Mineral oil does not.
Major Differentiating Factor
Tung oil can be used to protect wood from water, weathering, pests, and fungus. It is suitable for treating exterior wood, and forms a hard barrier.
Mineral oil can condition wood, but does not provide much protection.
When To Use Mineral Oil
Use mineral oil to remove temporary tattoos or makeup and to clean and condition skin.
Gently clean alabaster using a mineral oil-dampened rag.
Mineral oil is a lubricating laxative, which means it helps stool retain water and move through the intestines. It is not recommended for older adults, bedridden people, or children younger than six, but is safe to use in healthy adults and for many pets.
You can also use mineral oil to combat pest infestation on house plants (when mixed with a mild detergent), or on the feet of poultry.
Also see the similarities and differences in mineral oil and mineral spirits.
When To Use Tung Oil
Use tung oil as a penetrating wood finish for exterior furniture and trim. While it does not provide much impact protection, tung oil repels moisture and discourages mildew, mold, and pest infestation.
Use dark tung oil to darken wood, or pure tung oil for a golden glow.
Which Is Better, Mineral Oil or Tung Oil?
Tung oil is better at treating and protecting wood. Mineral oil is better for internal and topical applications, for a scientific culturing medium, and can also be used as a hydraulic fluid or as an electrical insulator.
