Gesso is vital for priming canvas or boards before painting. It seals the holes and provides a more paint receptive surface.
Without gesso, your canvas or board would be porous and lack some tooth, leading to a mottled and uneven texture. But for it to work effectively, gesso has to dry adequately in between coats and the final coat too.
Those new to gesso or just super excited to get down to painting always have questions. The most common ones surround the waiting time for gessoed surfaces to be ready.
How long does gesso take to dry? Gesso typically takes at least 10 minutes to dry to the touch and a couple of hours to be ready for paint. But the exact drying time varies greatly depending on a range of factors, including the airflow in the room and thickness of the coat.
Read on to find out more about these variables that influence the drying time of gesso. You’ll also learn a few tricks on how to make gesso dry much faster.
Factors That Influence The Drying Rate Of Gesso
If you’ve read this far, chances are that your gesso has been drying at a snail’s pace. You can’t help but wonder why it takes forever. Or, perhaps you feel impatient having read the label, which says 24 hours dry time, and you’re thinking that’s just too long to wait.
Regardless of whether you are unimpressed with the drying rate of your gesso or genuinely have no clue how long to wait, you shouldn’t be in a hurry. Gesso needs time.
It is always best to go with the manufacturer’s recommended time, which in most cases is 10-20 minutes in between coats and at least 24 hours full cure time. It may vary by brand. If you just can’t wait that long, you might be able to find an alternative to gesso that fits your timeframe better.
You can apply a second and third coat every 10 minutes or so when it is dry to dry touch. But to start painting, you have to wait for several hours. Notwithstanding, your gesso may still feel wet despite waiting for the stipulated time frame. Or even dry faster than you had anticipated.
Why? Because certain environmental conditions that were assumed when recommending the time frame fluctuate. Here are the factors that determine how long gesso takes to dry.
Temperature directly affects how quickly gesso dries. Gesso is water-based and dries by evaporation.
The higher the temperature, the shorter the time it will take for the gesso to dry. In low temperatures, the gesso will dry real slow. So if you are painting during summer, your gesso is likely to dry much faster than if painting during winter.
The level of humidity also impacts the speed at which gesso dries. Where there’s high humidity, the air is already dense with moisture. Consequently, the gesso will lose water much slower and stay wet longer.
On the contrary, when the humidity is low, the surrounding air has fewer water molecules, allowing the gesso to lose moisture quickly to its surroundings, drying faster.
So guys geographically based in the north or south, where humidity is always high, have to wait longer for the gesso to dry. Artists based in arid and semiarid areas experience low humidity, which supports rapid drying of gesso.
The airflow or air current also determines how long you’ll have to wait for the gesso to dry. When air moves, it lowers humidity by carrying away the water vapor through circulation.
This vapor-dense air is replaced by dry air. The cycle continues and promotes more evaporation. The air movement significantly cuts back the drying time of gesso. Where the air is still, humidity lingers around longer, slowing down the rate of moisture escaping from the coat of gesso.
4. The Thickness Of The Coat
Pre-primed canvas needs no gesso. But you can still apply one coat over it just to give it a power boost. Normally on raw surfaces, you must use at least three coats of gesso.
The number of coats of gesso and their thickness determines how fast it dries. Fewer coats typically dry much quicker. So do thinner ones.
5. How To Make Gesso Dry Faster
Temperature, humidity, and air currents are the three environmental conditions that influence the drying rate of gesso. Your geographic location and its weather patterns matter to some extent.
However, if you are painting indoors in a studio, these three conditions are likely different inside than outside. This is especially true because of heating and cooling systems, not to mention humidifiers and dehumidifiers.
Notwithstanding, sometimes the studio is in the basement or garage. Being separated from the main living area, you find that such systems are excluded in these spaces.
So what can you do to speed up the drying of gesso? Let’s find out.
6. Using A Box Fan
A box fan offers an easier way of lowering humidity by intensifying air circulation. You can also use a ceiling fan if you do not have a box fan.
However, a box fan has the advantage of mobility. You can bring it anywhere you enjoy painting. Place it closer to the wood or canvas to speed up the results.
Furthermore, it doesn’t need any muscle work or attention. You can leave it unattended as it does its job. To use a box fan layout, set the gessoed item in front of it; there can be several if needed.
7. Using A Hairdryer
A hairdryer offers a three-in-one solution to sluggishly drying gesso. One, it blasts hot air, therefore raising the temperatures. Two, it improves air circulation by blowing the air around. And lastly, it lowers the humidity levels.
The one downside to using a hairdryer is that it is labor-intensive, especially if you’re doing several pieces.
You would have to hold it for a while while you continuously move it around the canvas for even drying. Also, continuous motion prevents scorching a spot caused by building up heat in one spot.
Doing this for even an hour is a horrendous task, but it makes sure the gessoed surface dries in no time. You can also just do it for 5 minute spurts every now and then to gradually speed up the process.
8. Using A Heater Fan
You may also use a heater fan in place of a hairdryer. It works the same way, minus the sore muscles. Plus, unlike a hairdryer that may be incapacitated after running for an extended period, a heater fan is a sturdier device.
It blows hot air, which is beneficial for drying the gesso rapidly, especially when the surrounding temperatures are low.
9. Opening Windows
Sometimes a simple action like opening up the windows makes a world of difference when it comes to drying your gesso.
Remember, in an enclosed space, the air is sort of stagnated. But once you open the windows and let the breeze rush in, you improve the circulation. Moving air will help the moisture vanish much faster from the coat of gesso.
10. Taking It Outdoors
If the weather permits, you can apply and leave your gessoed surface outside to dry. A hot summer day when temperatures are high would be ideal. Even better with a light wind.
Just ensure that it is not under direct sunlight and that it is also protected from debris, hair, and anything that can be blown and get stuck on the wet gesso.
How Do You Know That Gesso Is Dry?
There’s no sure-fire way of knowing that your gesso is dry except by leaving it for a very long time. You can try and paint a small area, and if it doesn’t lift the gesso, it might be dry.
But sometimes, the gesso will dry superficially and still be soft deep inside. This often happens when the layer is too thick.
You can also touch the opposite side of the canvas with the back of your hand. It shouldn’t feel cold. If it does, it may be a sign that moisture is still lingering at the back.
Can You Paint Over Wet Gesso?
The short answer is no. You can not paint over wet gesso. It must be at least dry to touch. You could paint with acrylic paints on gesso that is dry to the touch, but not with oil paints. With oil paints, the gesso has to be fully cured.
Gesso contains water molecules that, if trapped beneath the paint, will compromise its adhesion. That is what will happen when you try to paint on wet gesso with oil paints.
And even though you could paint over partially dry gesso with acrylic paints, the results may leave a lot to be desired due to lifting. That’s because acrylic paints mix well with water (present in the gesso), but oil paints don’t.
So while adhesion of the acrylic paint may not be a problem, the colors will be tinted with white or whatever color the gesso is.