Spray paint takes around 10-30 minutes to dry to touch, 1-4 hours to dry enough between coats, and 12-72 hours to cure (dry fully).
To speed up spray paint dry time, use a hairdryer to increase the evaporation rate, ensure proper ventilation to increase the air circulation, or reduce the humidity by using a dehumidifier.
How Long Does Spray Paint Take to Dry Between Coats?
Spray paint takes around 1-4 hours to dry between coats. The exact dry time depends on the paint type, coat thickness, room temperature, and humidity levels.
For instance, spray paint takes longer to dry during cold (or moist) conditions as the evaporation rate is slower.
Water-based spray paint takes less time to dry between coats as it uses water as its solvent, and water evaporates faster. While oil-based spray paint takes longer to dry because its solvent (synthetic or natural oil) takes longer to evaporate.
The finish will turn sticky if you coat too soon as the solvent (of the existing coat) will be trapped between both coats. The coating is still wet if its solvent has fully evaporated, and this prevents a new coating from sticking and the existing coating from drying.
How Long Does Spray Paint Take to Cure (Fully Dry)?
Spray paint takes around 12-72 hours to cure (fully dry). Spray sealers, especially oil-based variants, take longer to cure due to the presence of gloss in the formula.
The cure time of spray paint refers to how long to wait until the finish fully dries and reaches its maximum durability, adhesion, and finish quality. The finish must fully dry (cure) to properly handle weights, foot traffic, spills, and cleaning.
For paint to cure, the solvent must fully evaporate from the coating and the particles must become rigid and compact enough. Spray paint cures through polymerization which takes longer to complete.
How To Speed Up Spray Paint Drying Time?
To speed up Spray paint drying time, do the following things.
- Use a Hairdryer.
- Ensure Proper Ventilation.
- Reduce the Humidity Levels
1. Use a Hairdryer
Since spray paint dries through evaporation, increase the evaporation rate to make it dry faster. To increase the evaporation rate, increase the heat around the coating using a hairdryer.
To use this method, you’ll need:
- A hairdryer
Here’s how to do it:
- Set The Heat To Medium – Set the heat of the hairdryer to low or medium.
- Hover The Hairdryer Around The Coating – Move the hairdryer over the coating. Ensure to cover all the areas of the paint and do not spend too much time on one part as the paint will dry unevenly. Do this for about 10 minutes.
- Turn Off The Hairdryer – Turn off the hairdryer and let the paint dry fully. Hairdryers are known to speed up paint drying by over 50%.
Note: Don’t dry the coating fully using a hairdryer as the particles will harden too fast and won’t have enough time to bond. This results in a weak and cracked finish that might peel off.
2. Ensure Proper Ventilation
The spray paint coating will dry faster if you increase the air circulation as that increases the evaporation rate. To increase the air circulation around a coating provide proper ventilation.
To ensure proper ventilation, do the following things.
- Open all doors in the room
- Open all vents and windows
- Turn on the fans
- Set the air conditioner on blow or fan.
3. Reduce the Humidity Levels
A high level of humidity will decrease the evaporation rate and cause water in the atmosphere to settle over the coating, causing a slower evaporation rate.
To reduce humidity levels, use a dehumidifier. Simply, plug in and turn on the dehumidifier and place it next to the coating.
The dehumidifier will suck in and trap moisture in the air while releasing cool dry air. You can use this method with any other method.
Here are some other tips you can use:
- Apply light coats. The lighter the coating, the faster it dries.
- Paint when the temperature is above 60 degrees F and humidity is less than 50%.
- Spray the paint outdoors for better ventilation.
How Long Does Spray Paint Take To Dry on Different Surfaces?
The Spray paint dry time for different surfaces is listed below.
Plastic
Spray paint takes around 1 hour to dry over a plastic surface. That’s because it can’t penetrate the slick material of the plastic, so the coating stays over the top layer and starts to dry immediately.
Wood
Spray paint dries within 2 hours on a wooden surface.
Since wood is a porous material it will absorb the paint deeply, which makes it difficult for the solvent to evaporate since most of it is soaked into the wood grain where there’s no air circulation.
Cardboard
Spray paints dries within 30 minutes over a cardboard.
Cardboards are light and porous, meaning the air circulation from both sides which increases the evaporation rate.
Metal
Spray paint takes around 30-60 minutes to dry over a metal surface.
Metal surfaces have high thermal conductivity, so when the weather gets hot its surface will get hot too, making the solvent evaporate faster.
However, during cold and moist conditions, the evaporation rate is slower.
Glass
Spray paints dry fast on glass because their surface is non-porous, so the coating doesn’t soak into the glass. Since most of the coating is exposed to air, the solvent evaporates faster. On average, a coating dries within 30 minutes over a glass surface.
Related Read: Can You Spray Paint Glass?
Plaster
Spray paint takes around 60-90 minutes (1/1.5 hours) to dry over a plaster surface.
Plaster surfaces are porous, so the coating soaks into the surface and takes longer to evaporate.
FAQ’s
How Long Must Spray Paint Dry Before Sanding?
Spray paint must fully dry (1-4 hours) before sanding it. The coating must be dry and rigid enough to handle the rough texture of the sandpaper.
You will remove the entire finish if you sand too soon.
What Happens if Spray Paint Dries Too Fast?
The finish will crack if the spray paint dries too fast. That’s because the particles must bond naturally for the finish to be durable and not crack.
If you speed up the bonding process (by using a hairdryer for too long), the particles won’t have enough time to harden and compact, so the coating won’t be durable.
Why Won’t Spray Paint Dry?
Spray paint won’t dry if you re-coat too soon, there’s a problem with the surface, the weather is too cold, the humidity level is too high, or you applied too much of it.
To fix this spray paint problem, you must first find the cause and then fix it.
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