Naphtha Vs. Mineral Spirits – Which to Use!

DIY’ers, painters, and mechanics can choose either naphtha or mineral spirits to thin paint and clean parts. Which of the two should you use for your next DIY project?

The main difference between naphtha and mineral spirits is that naphtha is used more in industrial applications that require more purity. The solvent is made from higher grade petroleum distillates, which can make using the solvent for DIY projects more expensive when compared to using mineral spirits. 

Below, you will learn what makes these two solvents similar and their differences.

What is Naphtha?

Naphtha is a petroleum distillate used in various industries as fuel and solvent. Manufacturers label naphtha by different names depending on its use, including light aromatic solvent naphtha and petroleum naphtha. 

DIY’ers can use naphtha instead of spirits when working with oil-based paint, wood, and more.

However, it is best for fuel since it is highly volatile and contains impressive chemical energy. Because of this, it is found in fuel for camp stoves, lighters, and more.

Industrial Use of Naphtha

Industries utilize naphtha as a raw material when making plastics such as polyethylene and polypropylene. These thermoplastic polymers are essential in producing various chemicals as well as bottles and plastic bags.

Because of its many industrial uses, millions of tons of this flammable liquid are used yearly.

Naphtha Fuel

Naphtha is excellent as a fuel since it contains an impressive amount of energy. We can get 3.14 megajoules of energy for every liter of naphtha.

If you plan on going camping anytime soon, you might take some naphtha on your trip as camping stove fuel. Naphtha also fuels blowtorches, lighter fluid, and more.

Not only does naphtha produce an extraordinary amount of energy to fuel various things, but it does so cleanly, making it a better choice over alternatives.

Naphtha Solvent

petroleum distillates

Naphtha is a common solvent that DIY’ers can use for different projects. This is a petroleum solvent used to thin oil-based paint, just like spirits. You can also use naphtha solvent to clean auto and machinery parts.

Because naphtha is a stronger solvent, it poses various hazards and can cause dermatitis irritation, making safety gear a must when applying it to paint or metal parts.

What are Mineral Spirits?

Mineral spirits are great as a solvent for projects that involve painting and degreasing parts. Many DIY’ers prefer spirits over other paint solvent products.

Mineral spirits are a solvent made from aliphatic and alicyclic petroleum-based compounds. DIY’ers and others use spirits to thin paint, degrease tools and parts, and clean. This solvent’s low price makes it a top choice among DIY enthusiasts.

Often, mineral spirits are labeled as paint thinner, and you will find them as white spirits outside of the US. Depending on where you live, you may or may not have access to spirits. However, there are alternatives for this solvent, such as naphtha.

Mineral Spirits or Naphtha to Thin Paint?

You can use both mineral spirits and naphtha to thin oil-based paint. Most DIY’ers prefer mineral spirits for this use since they are cheaper and more readily available in many places.

When choosing between these two cleaning solvents, something else to consider is that naphtha has a higher solvent strength than mineral spirits. You will use considerably less naphtha to thin the same amount of paint, but this does not necessarily mean spending less.

A gallon of naphtha can cost you considerably more than a gallon of mineral spirits. If you need to regularly use solvent to thin paint or for other purposes, spirits will help you keep costs down.

If you already have naphtha solvent stored and only need a little for a small project, you might as well use it.

The quality of the paint you are using will be the same regardless of whether you use spirits or naphtha.

Follow these steps to thin paint with spirits or naphtha:

1. Measure 4 ounces of solvent for every gallon of oil-based paint you want to thin.

2. Add the solvent slowly to the paint with one hand while mixing with the other.

3. If the consistency of the paint is not what you want it to be, add more mineral spirits.

Mineral Spirits or Naphtha to Clean Parts?

Cleaning or degreasing machinery parts is much easier, either with mineral spirits or naphtha. Again, what will primarily determine which you should use is how much you are willing to spend to get the job done. We recommend spirits since they are much cheaper solvents.

To get auto or machinery parts looking like new with mineral spirits or naphtha, do this:

1. Fill a container of proper size with the solvent.

2. Place the metal parts in the liquid to loosen grease and grime.

3. Wait a few minutes before taking the parts out of the solvent.

4. Use a scrub brush to eliminate grease and grime still on the parts.

5. Let the parts sit until solvent residue evaporates.

The evaporation rate of these two solvents is similar. Mineral spirits applied to surfaces evaporate in under 20 minutes. Naphtha takes slightly longer.

Safety Concerns of Mineral Spirits vs. Naphtha

Mineral spirits have low toxicity compared to other solvents you can get at a hardware store. Even so, the Occupational Health and Safety Administration (OSHA) advises DIY’ers to take safety precautions when using this solvent.

Mineral spirits can irritate and burn skin. This liquid is also highly flammable, so you should keep it far from sparks or heating sources. Naphtha carries the same risks but is a more powerful solvent. High naphtha exposure can lead to passing out, so you want to use a respirator.

Whether you use naphtha or spirits, you should do so outdoors or in a well-ventilated room. Prolonged exposure to toxic fumes from these solvents can cause respiratory problems.

Conclusion – Naphtha vs. Mineral Spirits

You can use naphtha and mineral spirits on all kinds of DIY jobs and to degrease tools and parts. Naphtha is more toxic and more expensive, so these two considerations make mineral spirits preferable for many.

If you have access to these solvents, you might want to try both to compare results firsthand and decide which is best for future projects.