Using a hair dryer will not effectively speed up the drying time of oil paints. Oil paints dry through oxidation and chemical reactions, not evaporation. In fact, applying concentrated heat from a hair dryer may cause cracking or other damage to an oil painting.
There are better ways to accelerate the drying time of oil paints. This includes using specialty painting mediums and thinners, painting in thin layers, allowing proper ventilation, increasing air circulation around the painting, and maintaining an optimal temperature.
Understanding the unique properties of oil paints is key to finding the right strategies for faster drying without compromising the paint’s integrity. With some adjustments to materials and methods, artists can reduce typical drying times from weeks or months to as little as overnight.
How Oil Paints Dry
Oil paints consist of dry pigments suspended in an oil medium, commonly linseed oil. As the painting layers are exposed to air, the oils oxidise, bonding with oxygen to form long polymer chains. This oxidation process slowly transforms the paint from liquid to solid.
Evaporation plays only a minor role in the drying of oil paints. Using a hair dryer does not provide enough concentrated heat to evaporate the oils. Instead, the chemical reaction with oxygen causes the paint to cure and harden over time.
Factors That Impact Drying Time
Many factors influence the drying time of oil paints:
Paint Layer Thickness
Thicker layers of paint take substantially longer to fully dry and cure than thin layers. Thick impasto paint may take 6-12 months to harden completely. Thin glazes can dry within hours or days.
Type of Oil Medium
Different oils undergo oxidation at different rates:
- Fast drying oils: safflower, poppyseed
- Moderate drying oils: walnut, sunflower, soybean
- Slow drying oils: linseed, tung
Linseed is the most common oil medium used in oil paints. Paints made with linseed oil take longer to cure than those made with faster drying oils.
Temperature, humidity, and air circulation all impact drying time:
- Cold temperatures slow the oxidation process, prolonging drying time.
- High humidity slows drying because moisture in the air hinders oxidation.
- Good ventilation and air circulation speed drying, allowing fresh air and oxygen to reach the paint layers.
Aim for room temperature between 65-75°F with 40-60% relative humidity. Avoid drafty spots which could blow dust onto the wet paint.
Some surfaces are more absorbent than others. Canvas and wood drink up the oils, leaving less on the paint’s surface. This allows for faster oxidation. Non-absorbent surfaces like metal or glass slow drying time.
Oil painting primers are formulated to help subsequent paint layers dry more quickly. Acrylic gesso or oil-based grounds absorb excess oils from the paint on top.
Drying Time of Oil Paints
The typical drying time for oil paints is:
- Touch dry: 24-48 hours
- Handle dry: 1-2 weeks
- Full cure: 6-12 months
“Touch dry” means the paint is dry enough to lightly touch without damaging it. At the “handle dry” stage, the painting is ready for varnishing or transport without the risk of smudging.
But a full cure takes much longer. Thick paintings may take up to a year to fully harden within the layers. It is best to wait at least 6 months before applying protective varnish.
Speeding Up Oil Paint Drying Time
There are several effective techniques to reduce the drying time for oil paints:
Paint in Thin Layers
Applying oil paints opaquely in thick, impasto layers means longer drying times. Instead, paint in multiple thin, transparent layers known as glazes. This allows faster oxidation as there is less oil to absorb oxygen.
Use Fast Drying Oil Mediums
Rather than using traditional linseed oil, switch to paint mediums made with fast drying oils like poppy, safflower or walnut oils. These speed chemical reactions compared to slower drying linseed oil.
Add Painting Mediums and Thinners
Specialty painting mediums and thinners are formulated to accelerate drying time in oil paints. Examples include:
- Japan dryer – Cobalt salts that catalyze oxidation. Can reduce drying time to 16-24 hours.
- Liquin – An alkyd resin that speeds drying and improves flow.
- Gamsol – A mineral spirits thinner that helps paint dry faster by diluting the oils.
Follow instructions carefully when adding mediums and thinners to maintain paint stability.
Allow Proper Ventilation
Ensure there is ample airflow in the room when working with oils. Open windows, use fans, or set up an easel near a vent to circulate fresh air. Oxygen is key for allowing the curing oxidation process.
Control Temperature and Humidity
Create ideal drying conditions. The optimal temperature range is 65-75°F with 40-60% relative humidity. Avoid painting in cold, humid environments. Consider using dehumidifiers, heaters, or fans if needed.
Use Absorbent Painting Surfaces
Prime canvas or wood supports with gesso or oil grounds. These absorbent layers will soak up excess oils from the paint on top, leaving less to oxidize on the surface.
Apply Heat Safely
While a hair dryer can actually damage oil paints, indirect heating can speed drying. Position a radiator, space heater, or incandescent lamp near the painting – but not close enough to cause cracking from direct heat.
Drying Oil Paints Overnight
By combining the techniques above, it is possible to reduce typical oil paint drying times from weeks/months to overnight:
- Paint thin layers using fast drying oil mediums.
- Add appropriate painting mediums and thinners.
- Paint on an absorbent primed surface like gessoed canvas.
- Create a warm (~70°F), ventilated environment for drying.
- Use indirect heat sources near but not aimed directly at the painting.
- Use a fan to keep air circulating around the painting as it dries.
- Avoid thickly applied paint layers.
Oil paints dried overnight may still feel a bit soft and require another day or two of curing to reach full hardness. But these methods allow painters to work in successive layers much more quickly than traditional oil painting techniques.
Hazards of Using a Hair Dryer on Oil Paints
Heating oil paints with a hair dryer can do more harm than good:
- The concentrated, direct heat can cause cracking or peeling in the paint layers.
- It only warms the surface while leaving underlying paint layers still wet.
- The strong air flow can potentially blow dust onto the tacky paint.
- It doesn’t provide ventilation to allow fresh air/oxygen to reach the lower layers.
- Most portable hair dryers do not get hot enough to speed evaporation of oils.
- Cracking or bubbling paint may resemble a dry surface but remain wet and uncured.
Instead of a hair dryer, rely on the abovementioned techniques to safely accelerate drying time.
- Oil paints dry primarily through oxidation, not through heat evaporating the oils.
- Many factors influence drying time, including paint thickness, type of oil, temperature, humidity, ventilation, and painting surface.
- Specialized painting mediums and thinners will speed drying time more effectively than a hair dryer.
- Thin layers dry substantially faster than thick paint.
- Ideal conditions are 65-75°F with ample airflow. Cold and humid environments prolong drying.
- With the right materials and methods, oil paints can dry overnight rather than over weeks or months.
- Never use a hair dryer on oil paints as the intense direct heat can damage the paint layers.
By understanding how oil paints cure and adjusting to painting techniques, artists can work efficiently and complete their oil paintings more rapidly.