Denatured Alcohol vs. Mineral Spirits – The Right Choice

As we all know, the usage of solvents is necessary for almost any woodworking project. With a wide variety of uses ranging from thinning finishes to cleaning wood, solvents are always helpful to ensure that your project goes smoothly.

Thanks to the advancements in technology, there are plenty of different solvents to choose from for your woodworking projects, with different strengths and weaknesses.

Denatured alcohol and mineral spirits are two of the most popular solvents in the woodworking world, and even though they can be used interchangeably at times, there are plenty of areas where they behave differently.

So, what are the differences between denatured alcohol and mineral spirits?

Mineral spirits are petroleum-based liquids commonly used for thinning paint. On the other hand, denatured alcohol is ethanol combined with additives that cause it to become toxic, taste bad, and smell bad to render it unfit for consumption. In woodworking, denatured alcohol is used to thin shellac.

While there are areas that both of these solvents overlap, such as cleaning brushes, they aren’t fully interchangeable due to the differences in chemical composition between the two.

What Is Denatured Alcohol?

To start, let’s dive deeper into what denatured alcohol is.

Denatured alcohol (also known as methylated spirits) is the combination of ethanol, certain additives, and dye. The additives and the dye cause the alcohol to be toxic, taste bad, smell bad, be visually unpleasant.

While the additives used to produce denatured alcohol vary, pyridine or methanol (both in some cases) can be found in almost all containers of denatured alcohol, making them highly toxic.

Even with these additives in play, the chemical composition of ethanol isn’t altered in the case of denatured alcohol, meaning that you can substitute ethanol in the place of denatured alcohol if needs be.

While denatured alcohol usually contains less ethanol by percentage due to the presence of other additives, both pure ethanol and denatured alcohol will get the job done for woodworking-related usage.

At this point, you may be wondering why denatured alcohol is even a thing, considering that pure ethanol works just as well. Simply put, the sole reason behind the addition of these additives is to make denatured alcohol unfit for human consumption.

This way, denatured alcohol becomes exempt from taxes added to alcoholic beverages, allowing you to purchase alcohol for a lesser price if you don’t intend to use it for recreational purposes.

While the most common use case for denatured alcohol is to use it as stove fuel, it’s also widely used in woodworking to thin shellac as alcohol is the only thing that can do so.

What Are Mineral Spirits?

Now that we have talked about denatured alcohol, it’s time to take a closer look at mineral spirits.

Mineral spirits (also known as white spirit, mineral turpentine, or petroleum spirits) are liquids that are made of petroleum, commonly used as an organic solvent in paint-related industries.

While regular mineral spirits have toxic fumes that are accompanied by an unpleasant smell, odorless mineral spirits also exist where the odors and the toxicity are mostly removed, catering to fields such as oil painting where one has to stay in close contact with the mineral spirits for extended periods.

As an organic solvent, mineral spirits are very flexible and are used in many areas such as solvent extraction, cleaning (paintbrushes, painting tools, paint spills, wood furniture), degreasing (automobile parts, machine parts, tools), and thinning (paints, varnishes, lacquers). That being said, the most common uses for mineral spirits are thinning paints and varnishes, and in fact, mineral spirits are the most used solvent in the paint industry.

Depending on the distillation process and the type of crude oil used during production, mineral spirits are separated into three different types, with each type corresponding to a flash grade (referring to flash point).

  1. Type 1 (Low flash) – Mineral spirits that have been hydrodesulfurized belong to this category. In the North American region, these mineral spirits are also called Stoddard solvents. They have a flashpoint of 70 to 86 degrees Fahrenheit.
  2. Type 2 (Regular flash) – Mineral spirits that have been solvent-refined belong to this category.They have a flashpoint of 88 to 129 degrees Fahrenheit.
  3. Type 3 (High flash) – Mineral spirits that have been hydrotreated belong to this category. They have a flashpoint of over 131 degrees Fahrenheit.

Of the three types, Stoddard solvent (type 1) is the variant we refer to when we say mineral spirits.

As the process for increasing the flashpoint also causes the mineral spirits to become heavier, the drying times of such a product are way longer than what is desired for home usage. Combined with the fact that home usage doesn’t require high flashpoints, type 1 mineral spirits are the most suitable option.

Differences Between Denatured Alcohol and Mineral Spirits

Now that we have a better understanding of both of these solvents, it’s time to compare the two and see how they differ from each other.

  1. Mineral spirits and denatured alcohol consist of entirely different materials. While denatured alcohol is made mostly of ethanol and some additives, mineral spirits are completely petroleum-based.
  2. Denatured alcohol dissolves in water; mineral spirits don’t. Just like all other alcohols, denatured alcohol also dissolves in water. On the other hand, mineral spirits dissolve in water as they nonpolar solvents.
  3. Denatured alcohol evaporates much faster than mineral spirits. Due to its chemical composition, denatured alcohol dries a lot faster than mineral spirits. While this can be considered to be an advantage, it also means that your denatured alcohol will quickly evaporate if not stored properly.
  4. Mineral spirits leave an oily residue behind after they evaporate. That being said, this residue can be cleaned rather easily with soap and water and does not cause much of an inconvenience. On the other hand, denatured alcohol evaporates completely without leaving anything behind.
  5. Denatured alcohol has a much stronger smell than mineral spirits. Due to the additives that are added into denatured alcohol to deter people from consuming it, it has a pretty strong smell that can get uncomfortable rather quickly. While mineral spirits also have an odor, it’s much less when compared to denatured alcohol. On top of this, it’s also possible to find odorless mineral spirits.
  6. Mineral spirits are toxic when inhaled for long periods. Prolonged exposure can cause effects such as dizziness, nausea, and even unconsciousness.
  7. Denatured alcohol can thin shellac; mineral spirits can’t. Alcohol is the only thing that you can use to thin shellac. Due to their chemical composition, mineral spirits won’t even mix with it.

Similarities Between Denatured Alcohol and Mineral Spirits

While there are plenty of differences between these two solvents, there are also a few similarities.

  1. You can use both denatured alcohol and mineral spirits to clean your paintbrushes, paint sprayers, and other tools. If you’re looking to clean your tools, both of these products will do the job without issues as they are capable of dissolving paint, glue, wax, grease, and other unwanted substances.
  2. You can use both of these products to remove stains from wood. Both mineral spirits and denatured alcohol are quite effective when it comes to removing stains from wood. By wiping the surface with either of these products, you will easily be able to get the stains off.
  3. You can use both of these products to thin paint. That being said, using denatured alcohol to thin paint isn’t recommended as it can cause paint to dry up rather quickly, so keep it in mind as a last resort solution and not an everyday one.

Can You Mix Denatured Alcohol and Mineral Spirits?

Denatured alcohol and mineral spirits won’t mix, and there is no reason to try to mix them either.

Both mineral spirits and denatured alcohol are capable of acting as a solvent by themselves (with different use cases), and attempting to combine them wouldn’t achieve anything at all.

What Are Substitutes for Denatured Alcohol?

We have established that we can’t directly replace denatured alcohol with mineral spirits.

So, what can you use if you don’t have access to denatured alcohol?

  • Ethanol – We have been talking about how denatured alcohol is the combination of ethanol and other additives, which means that ethanol is a perfectly fine substitute to denatured alcohol as they are practically the same thing at the end of the day.
  • 99% Isopropyl Alcohol – If you don’t have access to denatured alcohol or another form of ethanol, isopropyl alcohol also does the job. Ensuring that your isopropyl alcohol is 99% is significant as lower-proof IPA (rubbing alcohol) won’t be as effective due to the high content of water.
  • High-proof Grain Alcohol (Everclear, Golden Grain, etc.) – Even though it will cost you more than ethanol or isopropyl alcohol, high-proof grain alcohol is a suitable substitute to denatured alcohol when all else fails. For instance, it’s possible to find 189-proof and 190-proof bottles of Everclear, which are pretty close to denatured alcohol in terms of alcohol content.

What Are Substitutes for Mineral Spirits?

Finally, let’s go over some products that you can use as a substitute for mineral spirits.

  • Turpentine – Turpentine can be used as a direct replacement for mineral spirits in all areas. Compared to mineral spirits, turpentine is known to have less odor and be less sticky.
  • Acetone – While acetone can be used as a substitute for mineral spirits, direct contact can cause damage to the wood. For this reason, it’s essential to be careful while dealing with acetone.
  • Paint Thinners – As the term paint thinner is an umbrella term used for products such as turpentine, mineral spirits, or acetone, it’s not exactly an alternative to mineral spirits in the traditional sense. That being said, any container labeled as “paint thinner” can be used as a substitute for mineral spirits with proper care.

Wrapping Up

Even though mineral spirits and denatured alcohol can be used interchangeably for cleaning purposes, they are quite different than each other in many ways ranging from how they are produced, the areas they are used in, and their chemical properties.

Considering that alcohol is the only thing that can thin shellac, and mineral spirits do a better job at everything else, such as thinning paint or cleaning, it’s best to keep a container of both denatured alcohol and mineral spirits.