Mineral Spirits vs. Paint Thinner: What’s the Difference?

Mineral Spirits

Lee Wallender

Mineral spirits and paint thinner are indispensable solvents for thinning oil-based paint, stains, and varnishes, as well as for cleaning up paint equipment and oily materials.

Water-based latex paints have evolved and have become more prevalent in the home—to the point where oil-based products that require mineral spirits or paint thinner are used less frequently. Yet some professional painters and do-it-yourselfers still prefer oil-based paint for its ability to self-level and remain streak-free. Plus, many stains and varnishes are still oil-based, as well. Water cannot be used as a solvent for any of these products.

Is there any difference between mineral spirits and paint thinner? If so, which of the two should you purchase when painting, staining, or cleaning?

What Mineral Spirits Is

Mineral spirits is made of 100-percent petroleum distillates and has no additives. Mineral spirits is a clean, clear product that's used for thinning oil-based paint. It can also be used for thinning or cleaning stains and varnishes, as well as for cleaning up oil stains or spills.

When thinning paint with pure mineral spirits, start with 4 ounces of mineral spirits per gallon of paint. Add only to oil-based paint and never to water-based paint. Water-based paint (the majority of the acrylic-latex paints now sold) is thinned out and cleaned up with water.

Pros
  • Effective with oil-based products

  • Inexpensive

  • Clear, low odor

Cons
  • Toxic

  • Does not work well with asphalt products

  • Flammable

What Paint Thinner Is

Mineral spirits-based paint thinner is often blended with additives such as trimethyl benzene (benzene).

Sometimes, paint thinner is mineral spirits with no additives, as well. Some paint thinners even advertise "made with mineral spirits" on the can.

It's important to remember that paint thinner describes the function of the product, not necessarily its makeup. So, paint thinner can essentially be anything that thins paint. Even citrus-based products or turpentine, which is derived from pine trees, could be called paint thinners. Since water thins out water-based latex paints, water, too, can even be called paint thinner.

Four ounces of paint thinner per gallon of oil-based paint is usually the recommended starting point. More can be added.

Mineral Spirits vs. Paint Thinner

Mineral Spirits
  • 100-percent petroleum distillates

  • Mineral-based

  • No additives

  • Around $13 to $14 per gallon

Paint Thinner
  • Anything that thins paint, but typically means petroleum-based thinner

  • Often mineral-based

  • Sometimes has additives

  • Around $9 to $10 per gallon

  • Mineral spirits is a term that specifies the product's composition, while paint thinner is a generalized term that describes the product's function, not its composition.
  • Both products are derived from minerals. This distinguishes them from products such as turpentine that are derived from living pine trees or citrus rinds.
  • Generally, mineral spirits and paint thinner are interchangeable products.
  • Mineral spirits sometimes is lower in odor than paint thinners.
  • Mineral spirits cost around 45-percent more than paint thinner, on a gallon-by-gallon basis.
  • As a general term, paint thinner can mean anything that thins or cuts paint, including products advertised as safe, green, or eco-friendly that have as little as 15- to 40-percent petroleum distillates. It can even mean products that have no petroleum content, such as turpentine.

Composition

Mineral spirits is derived from minerals: in this case, petroleum. All products labeled as mineral spirits should contain 100-percent mineral spirits, unblended and with no additives. Pure mineral spirits is a paint thinner.

Products labeled as paint thinner can refer to pure mineral spirits, blended mineral spirits, turpentine, acetone, naphtha, or any number of other products capable of thinning oil-based paint. Most often, though, paint thinner means less refined mineral spirits with 5-percent or less benzene content added for better solvency and aroma.

It is important to distinguish the class of blended and unblended mineral spirits from other classes of products capable of thinning paint. The former class, derived from petroleum, is clear, non-sticky, and relatively odor-free. The latter class can include products such as turpentine, derived entirely from pine tree oleoresins and with no petroleum content. In fact, due to turpentine's foul odor and caustic nature, mineral spirits, often called white spirits, were developed as a safer, gentler solvent.

Also, those blended and unblended mineral spirits differ vastly from solvents commonly advertised as paint strippers or paint removers. These solvents, meant to dissolve hardened paint, contain a host of chemicals such as alcohol, methanol, and xylene, to name only a few.

Odor

Both unblended mineral spirits and blended mineral spirits called paint thinners have an odor similar to camping lantern oil or kerosene. Due to the added benzene, paint thinner will have more of an odor than will pure mineral spirits. The smell is typically sweet and most users do not find it objectionable. Due to the difference in odor, pure mineral spirits tends to be better for interior use.

Generally, both straight mineral spirits and mineral spirits-related paint thinner are low in odor in comparison to the foul, chemical-like smell of other classes of paint thinners.

Safety

Pure mineral spirits and related paint thinner have no difference in terms of safety. Both products are equally toxic.

Each product ranks the same in all safety categories of the OSHA-mandated Safety Data Sheet (SDS) for paints and solvents. When inhaled, benzene can cause drowsiness and even can render a person unconscious.

Long-term exposure in high quantities may adversely affect your health. For that reason, always make sure that you are working in a well-ventilated area when using mineral spirits with added benzene.

Cost Difference

Mineral spirits usually costs more than blended paint thinners. Generally, pure mineral spirits will cost about 40- to 50-percent more than mineral spirits-based paint thinners with additives.

Common Uses for Mineral Spirits and Paint Thinner

  • Thinning oil- or alkyd-based paints while those paints are still in soluble form
  • Cleaning brushes that have wet paint on them (not dried or hardened paint)
  • Removing waxy films on wood surfaces
  • Soaking and cleaning oily car parts
  • Degreasing or cleaning oily equipment or tools
  • Cleaning spray equipment
  • Removing sticky adhesives
  • Eliminating heel and scuff marks from flooring

Uses to Avoid

  • Neither mineral spirits nor paint thinner will act as a paint stripper or remover for paint that has already cured (dry paint must be mechanically removed or stripped away with chemical paint strippers).
  • Do not try to clean off paint or any other substance from an asphalt driveway or walkway. Either product will soften the asphalt.
  • Never use mineral spirits or paint thinner for cleaning latex paint from brushes or surfaces.
  • Never attempt to use either mineral spirits or paint thinner as a fire starter for charcoal, wood, or any other type of flame.

Should You Buy Mineral Spirits or Paint Thinner?

For most residential users, mineral spirits and paint thinner can be used interchangeably.

Both mineral spirits and paint thinners that are blended mineral spirits perform largely the same functions. Both are clean, clear, and non-sticky solvents for thinning and for cleaning oil-based paints, stains, and varnishes.

Pure mineral spirits is considerably more expensive than paint thinner. For large, commercial projects, the 40- to 50-percent price difference might be noticeable. For most do-it-yourselfers and homeowners, though, the $4 to $5 price difference shouldn't matter since solvents of this type are used sparingly.

Because pure mineral spirits has a lower odor, it is best for indoor use.