Turpentine is a solvent distilled from pine trees, used primarily to thin oil paints, clean brushes, and strip finishes from wood surfaces. It works by dissolving oils and resins, making it a staple in art studios and woodworking shops. Using it safely and effectively comes down to knowing the right ratios, choosing the right type, and protecting yourself from its fumes.
Types of Turpentine
Not all turpentine is the same product. The two main types you’ll encounter are gum spirits of turpentine and wood turpentine, and they’re made differently.
Gum spirits of turpentine comes from the resin (sap) of living pine trees. Workers tap the tree, collect the resin, and then steam-distill it. The result is a mixture of essential oils and resin acids. It has a milder smell and is considered the higher-quality option, favored by fine artists and sometimes used in perfume and flavoring production.
Wood turpentine is made by heating pine wood in a closed container and condensing the vapors that come off. It’s harsher, with a stronger odor, and is more commonly used as an industrial solvent for paints, varnishes, and coatings. For most home and art studio purposes, gum spirits of turpentine (often labeled “pure gum spirits” or “rectified turpentine”) is the better choice.
Thinning Oil Paints
The most common use for turpentine is thinning oil paint. A standard starting ratio is 2 parts oil paint to 1 part distilled turpentine. This produces a noticeably thinner consistency and shortens drying time, which makes turpentine-thinned layers ideal for the early stages of a painting where you’re blocking in shapes and base colors.
You can add more turpentine for an even thinner wash that dries faster, or less for a thicker layer. The key principle to follow is called “fat over lean”: start with turpentine-heavy (lean) layers at the bottom and use progressively less turpentine in each layer as you work toward the surface. This prevents cracking, because lean layers dry faster than fat (oil-rich) ones. If you put a fast-drying layer on top of a slow-drying one, the surface dries and contracts while the layer beneath is still wet, causing cracks over time.
To mix, pour a small amount of turpentine into a palette cup or jar, dip your brush, and blend it into the paint on your palette. Add turpentine gradually rather than dumping it in. You want control over the consistency.
Cleaning Brushes and Equipment
Turpentine dissolves oil paint effectively, making it a go-to brush cleaner. Swirl your brushes in a jar of turpentine until the paint loosens, then wipe them on a rag. For brushes caked with dried paint, let them soak in turpentine for 15 to 30 minutes before working the bristles clean.
You don’t need to throw out used turpentine after one cleaning session. Pour it into a sealed glass or metal container and let it sit undisturbed. Over several weeks, the paint sludge will settle to the bottom. You can then pour off the clear turpentine on top and reuse it. If you want to speed things up, strain it through a coffee filter to remove the suspended pigment. Dry the collected sludge outdoors and discard it with your regular trash once it’s fully solid.
Wood Finishing and Stripping
Beyond painting, turpentine works as a solvent for thinning oil-based varnishes and wood stains. It can also help remove old wax finishes from furniture. Apply it with a rag, working in the direction of the wood grain, and wipe away the dissolved finish. For thinning varnish, follow the ratio on the product label, as different varnish formulations need different amounts of solvent.
Turpentine also cleans grease, tar, and adhesive residue from surfaces. A small amount on a cloth will dissolve sticky spots that water and soap can’t touch.
Safety Precautions
Turpentine is toxic. Its fumes irritate your lungs and nervous system, and prolonged skin contact can cause irritation or allergic reactions. The effects of inhaling turpentine include dizziness, drowsiness, headache, and difficulty breathing. At high concentrations, exposure can cause tremors, seizures, and unconsciousness. Swallowing turpentine is a medical emergency that can lead to blood in the urine, kidney failure, throat swelling, and convulsions.
Ventilation is the single most important safety measure. Work with windows open and, ideally, a fan pushing air out of the room. If you’re using turpentine in an enclosed space or for extended periods, wear a respirator fitted with organic vapor cartridges. A simple dust mask does nothing against turpentine fumes.
Wear chemical-resistant gloves (nitrile works well) to keep turpentine off your skin. If it does get on your skin, wash the area immediately with soap and water. If it splashes into your eyes, flush them with clean water for at least 15 minutes. Avoid eating, drinking, or touching your face while working with turpentine.
Fire Risk and Storage
Turpentine is flammable, with a flash point of 95°F (35°C). That means it can ignite from a spark or open flame at temperatures you might encounter on a warm day or near a heat source. Keep it away from radiators, space heaters, pilot lights, and direct sunlight.
Store turpentine in its original container or in a UL-approved metal safety can with a tight-fitting lid. Glass jars with screw-top lids also work for smaller amounts. Keep containers sealed when not actively pouring. Store them at room temperature in a well-ventilated area, away from living spaces if possible, such as a detached garage or shed.
Rags soaked in turpentine pose a real fire hazard. As the solvent evaporates, the process can generate enough heat in a crumpled, bunched-up rag to cause spontaneous combustion. Lay used rags flat outdoors to dry completely before discarding them, or store them in a sealed metal container with a lid until you can dispose of them properly.
Disposal
Turpentine is classified as household hazardous waste. You should never pour it down a drain, into a storm sewer, or onto the ground. For small leftover amounts (less than one cup), mix the turpentine with an absorbent material like plain clay cat litter (no additives or fragrances). Spread the mixture outdoors and let it dry completely. Once dry, wrap it in a plastic bag and put it in your regular household trash.
For larger quantities, check with your local waste management authority. Most municipalities run periodic hazardous waste collection events where you can drop off solvents, paints, and other chemicals for free. Many hardware stores and recycling centers also accept used solvents year-round.
Turpentine Is Not Medicine
Some corners of the internet promote drinking turpentine or “gum spirits” as a folk remedy for parasites, candida, and other conditions. This is dangerous misinformation. Turpentine is a poison. Ingesting it can cause kidney failure, seizures, throat swelling that blocks your airway, and death. The National Institutes of Health classifies turpentine ingestion as poisoning, with symptoms affecting the kidneys, lungs, and nervous system. There is no safe internal dose. Keep turpentine out of reach of children and never use it on or in the body.