Painters use solvents to preserve their paints for longer. They save costs on art supplies by thinning out oil paint. Also, solvents make it easier to paint and shorten drying times.
Two of the most popular solvents are mineral spirits and turpentine. These paint thinners can expedite the painting process by breaking down the oil and pigments to create a watery consistency.
Artists use solvents in first wash and underpainting to create a base to add upon. While you should use them in moderation, solvents are an excellent tool to extend the longevity of your paints when crafting a work of art.
What Are Mineral Spirits?
Mineral spirits are solvents made from petroleum. These white spirits double as cleaners and degreasers. In art, mineral spirits work as a mild solvent and paint thinner. These solvents are widely available and cheap, but they may leave an oily residue on your painting.
Many artists prefer mineral spirits for their unscented nature and fatty consistency. You will need to buy an artist-grade solvent that will maintain the oil in your paint without going overboard.
What Is Turpentine?
Turpentine is a solvent made from distilled tree resin, usually pine. It functions as a paint thinner, degreaser, or cleaner. Historically, turpentine had been used as a medicinal elixir for topical treatments, and you can still find it in Vicks chest rubs. However, it is dangerous for consumption. This watery solvent will not leave an oily residue on your painting.
If you want to go with turpentine, you will need to find artist-grade turpentine that is highly refined with reduced potency.
Mineral Spirits vs. Turpentine
Since mineral spirits and turpentine have many of the same functions, what are their differences?
Composition
Mineral spirits are made of alicyclic and aliphatic petroleum compounds. They are made by distilling cyclopropane, aliphatic, and aromatic compounds.Pure mineral spirits have a highly corrosive nature, making them useful for stripping paint. You will want a less volatile option with a high flash point, such as Type II mineral spirits. These have fewer aromatic solvents to make them suitable for thinning oil paint.
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Turpentine is harvested from living trees. Most turpentines come from pine trees, especially the Aleppo, loblolly, longleaf, maritime, Masson’s, ponderosa, and Sumatran pines. You can find some brands sourced from terebinth, balsam fir, larch, and other trees.
Turpentine will remove the bark from a tree and collect the oleoresin secreted by it. The crude oleoresin gets evaporated in a copper still to separate the distilled turpentine from the molten rosin.
Ideal Uses of Mineral Spirits and Turpentine
Both mineral spirits and turpentine work well to thin paint. However, mineral spirits are more potent than turpentine. Also, their oily consistency will preserve some of the oil paint’s texture without overwatering it.
Turpentine works better for cleaning than mineral spirits because it leaves no residue behind. You can use it to clean rollers, brushes, trays, and spray guns. Make sure to dry your parts thoroughly after cleaning to prevent rust.
You can soak any tools in turpentine to remove grease as well. It also cleans up paint spills and stains quickly with a soak or a wipe. Mineral spirits also work to degrease and clean, but they may leave a thin, oily residue behind.
However, you should not clean any kind of plastic with mineral spirits or turpentine. These include thermoplastics, thermosets, and elastomers (rubbers). The solvents may dissolve some of the material.
Overall, you can use either solvent for thinning paint, cleaning, or degreasing. If you have both on hand, you may want to devote the mineral spirits for paint and the turpentine for cleanup.
Drying Times
Since turpentine is more watery than mineral spirits, it dries much faster. Regardless, both will accelerate the drying time compared to standard oil paint.
If you want to speed up the drying time further, ensure you paint in thin layers. Store the artwork in low humidity, dry areas. You can also keep a dehumidifier in your studio.
Using any solvent should dry your painting in under 24 hours. If you need it dry sooner, you may prefer turpentine to white spirits.
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Storage and Safety
Make sure you buy a refined, artist-grade solvent. Unrefined mineral spirits have toxic aromatic compounds, so you will want to get odorless mineral spirits to keep them safe.
When you get a white spirit on your skin, it can cause irritation. Also, it has low acute toxicity when consumed. If you ingest large doses or have repeated exposure, you may suffer side effects like contact dermatitis, forgetfulness, aspiration, nausea, dizziness, and central nervous system issues.
Mineral spirits do not create significant environmental hazards, but they should be kept away from marine ecosystems due to their toxicity to aquatic organisms.
Place them in a latched container and keep them away from children and pets since they may resemble water. You may want to print out a label expressing its danger.
Turpentine can damage the skin, eyes, respiratory system, renal system, and nervous system. Side effects include vomiting, burning sensations, convulsions, confusion, unconsciousness, diarrhea, nausea, abdominal pain, tachycardia, respiratory failure, and death in large doses.
Ensure you handle undiluted turpentine with protective gear to prevent contact and ingestion. Store it in a place where it won’t interfere with the environment, animals, or children in a secure and clearly labeled container. While not as hazardous to the environment as mineral spirits, turpentine is more toxic to humans.
Where to Buy
You have to go with artist-grade solvents to protect you and your work. They are pricier than the ones in hardware stores, but they will still last a long time. You can find mineral spirits and turpentine at most art supply stores locally or digitally.
Disposal
You dispose of mineral spirits and turpentine in the same manner. To get rid of them, research a nearby disposal site for hazardous chemicals. Take it to one of these facilities when you run out.
Mineral spirits will evaporate in time, but you will always need to take turpentine to a disposal facility. If you have leftover solvents, you can use them for cleaning tools. Save any runoff solvents by straining solid parts and pigments to reuse for cleaning.
Final Thoughts: Mineral Spirits vs. Turpentine
If you want to thin oil paint to extend its use, consider getting a solvent. Both mineral spirits and turpentine have their benefits, and you will do fine using either to paint the base layer of your painting.