Mineral Spirits vs Mineral Oil

Two substances created during petroleum processing are mineral spirits and mineral oil. Find out more about each of these products and the similarities and differences between them. After revealing the major differentiating factor, I’ll explain which is better. I’ll also give you the rundown on when to use mineral spirits, and when mineral oil is a better choice. 

What Are Mineral Spirits?

Mineral spirits, also known as ‘white spirits’, are a clear liquid with the power to dissolve other substances such as resins, binders, and adhesives. They are made from petroleum. 

Mineral Spirit Uses

Mineral spirits are most commonly used as a thinner for oil-based paints and varnishes.  When unrefined, the same substance is marketed as ‘paint thinner’, but this product releases more VOCs and has a stronger odor than mineral spirits. 

Mineral spirits are versatile, and can also be used to refresh and revive film-forming wood finishes. Wiping varnishes and lacquers with a rag dampened by mineral spirits will cause the top layer of finish to dissolve and re-harden, evening out any dings or dents in the surface. 

Read more in my article comparing mineral spirits and denatured alcohol.

You can also use mineral spirts to thin wood stain before you apply it to the material. Or, you can use it to thin other wood finishers like polyurethane.

When acting as a cleaner, mineral spirits are used to dissolve automotive grease, leaving metal parts both clean and dry. It is so effective at degreasing that metal cleaned with mineral spirits sometimes must be relubricated after it dries. 

Both natural and synthetic adhesives release their grip when exposed to mineral spirits, making it a useful substance to keep in your workshop. Price tags or stickers can be wiped off of wood, metal or glass using mineral spirits. 

They make it easy to clean up after oil-based projects. However, mineral spirits are not an effective cleanser for water-based or acrylic paints. Mineral spirits are generally not advised for use on plastics. If the plastic was made with mineral spirits or other chemically similar components, the mineral spirits may cause the plastic to degrade. 

Yet another application for mineral spirits is to remove sap from gardening tools. Not only will they return to a usable state, they’ll be bright and shiny. 

Within a half hour of application, mineral spirits fully evaporate, leaving no residue behind. This makes them ideal for preparing surfaces to accept finishing products and adhesives. 

What Is Mineral Oil?

The name ‘mineral oil’ has been used throughout history to refer to a number of different substances. It can best be understood as a group of oils that originate from non-vegetable sources. Mineral oils are clear, odorless, and inedible. 

Mineral Oil Characteristics

Mineral oil is usually created as a byproduct of petroleum production. It’s functions are many and varied, and span the medical, mechanical, electrical, industrial, cosmetic and food production industries. 

Mineral oil does not conduct electricity and displaces air and water, so it is suitable for insulated heating and cooling units. It is often referred to as ‘transformer oil’. It cannot be compressed, so mineral oil can also be used as a hydraulic fluid. It has poor biodegradability. 

The physicists at Fermilab chose to collide particles at high speeds in a tank filled with mineral oil during their well-known MiniBooNE experiment, filling a tank with over 250,000 gallons of super-pure mineral oil. 

Mineral Oil Uses

• Mineral oil is a mild laxative, and can be safely used in humans or other animals such as cats, dogs, and livestock.
• When scaly mites infect poultry, a layer of mineral oil will clear the infection by suffocating the mites.
• Mixing it with detergent allows it to be sprayed onto household plans, achieving a similar pest-controlling effect. 
• Highly refined mineral oils are used in skin products and cosmetics such as cold creams and various ointments, because they don’t clog pores. When combined with a fragrance, mineral oils are marketed as ‘baby oil’.
• Mineral oil will remove temporary tattoos.
• These kinds of mineral oils can also be used as a vaginal lubricant. 

The most refined mineral oils are used in the culture of oocytes and embryos during IVF. It provides a layer of thermal protection and, by holding the organisms in place, allows for the culture of more oocytes in a single dish. 

Food-grade mineral oils are used in the formulation of popular candies for a glossy finish that doesn’t stick, although it is not certified for this use inside the European Union. 

Alabaster, a soft, carveable metamorphic rock, can be ruined if exposed to water. However, alabaster can be safely cleaned and polished with mineral oil. Wooden food service items in need of conditioning will benefit from being rubbed down with mineral oil as well. 

Special machines can burn mineral oil, producing a thick white smoke that can be vented into a closed container, exposing any air leaks. This is part of completing an automotive evaporative emissions test. 

Fire-breathers and fire-dancers in search of an odorless fuel to use in their performances sometimes turn to mineral oil instead of carcinogenic naphtha or stinky kerosene. 

Mineral Spirits vs Mineral Oil

Besides the word ‘mineral’ in the same, do these two substances have anything in common? In the end, the only thing mineral spirits and mineral oil have in common is that they share the word “mineral”.

There are a few similarities between mineral oil and mineral spirits, but the differences are much more substantial. 

Similarities

Although both substances are clear, flammable, and petroleum based, they don’t have much else in common.

Petroleum-based

Both mineral spirits and mineral oil are by products of the petroleum-refining process

Transparency

Both mineral spirits and mineral oil are clear. 

Inflammability

Storing mineral spirits or mineral oil away from heat and open flames is essential. When working with either substance, keep away from sources of ignition. 

Differences

There are many important differences between mineral spirits and mineral oil. They include their appearance, odor, and use, their food safety ratings, and their overall toxicity. 

Use

Mineral spirits and mineral oils are used for completely different things.

Mineral spirits dissolve grease, adhesive, and thin oil-based paint. Mineral oils are used for everything from softening the skin of infants to insulating electrical transformers. 

Odor

Mineral oils are odorless. Mineral spirits have a strong, kerosene-like scent that is considered unpleasant by most people. 

Viscosity

Mineral spirits flow like water. Mineral oil is much more viscous. 

Food Safety

Mineral oil can be safely used to condition wooden food service items such as salad bowls, butcher blocks, and the handles of serving utensils. Mineral spirits are not food safe, and should not be used on anything that will come into contact with food. 

Major Differentiating Factor

Mineral oil is non-toxic, food safe, and safe for internal and external human use. It can be given to animals or people as a mild laxative and is gentle enough to rub on your baby. 

Mineral spirits are not safe for internal or external human use and should not be ingested. When swallowed or excessively inhaled, a serious condition known as mineral spirits poisoning can occur. 

When to Use Mineral Spirits

Use mineral spirits to remove sticky substances from wood or metal, to thin oil-based wood finishes, and to revive and rejuvenate an old wood finish. 

When to Use Mineral Oil

Use mineral oil to condition wooden countertops, cutting boards, salad bowls, and other wooden cooking and serving implements. 

It can also be ingested by you or your pet when a mild laxative is needed. It lubricates and conditions sensitive skin, and removes temporary tattoos. 

If you’re a firebreather or firedancer, use mineral oil for an odor-free alternative to kerosene and other fuels. 

Which Is Better, Mineral Spirits or Mineral Oil?

Mineral spirits are better at thinning oil paints, degreasing automotive parts, and removing adhesive. 

Mineral oils are better at conditioning skin and wood, controlling pests in household plants and poultry, and producing a laxative effect in animals and humans.