Sticky or tacky acrylic paintings can be annoying to all artists. If you are a beginner, you might wonder, why your acrylic paint is sticky.
Acrylic painting is sticky when the painting is not fully cured, has poor ventilation, high humidity, uses low-quality paints, and thick painting layers. Avoiding the above aspects when painting, finishing with varnish or sealer, and using parchment papers in between paintings can fix this problem.
To prevent the acrylic paint from sticking, all the steps from preparing the surface to applying a sealer or varnish are important. If you follow all of those steps correctly, your paintings will not be sticky or tacky.
Why acrylic painting is sticky?
Acrylic paint becomes sticky between its wet phase and fully cured phase. Although the paint is dry to the touch, there is still water and solvent left in the paint film, causing stickiness. Poor ventilation, high humidity, low temperature, quality of paint, and thick paint layers may also contribute.
I have elaborated on each factor that can cause your acrylic painting to be sticky below.
Your painting has not been fully cured
There are two distinct drying phases to acrylic paint as mentioned before. In the first phase, the skin will be formed over the surface of the paint film and the paint will be ‘dry to touch’. This phase is very short and may even be seconds when the paint is applied very thinly. If paints are applied thickly, the first phase may last for one day or more.
On average acrylic paint will be dry to touch within 20 to 30 mins. However, what most artists are not aware of is the second phase of drying, which is called the ‘curing period’. The curing period is longer than the first phase of drying.
Stickiness happens when acrylic paint is not fully cured. When there is still water and solvent left in the paint film and the paint hasn’t hardened fully, acrylic paint will be sticky. For very thin acrylic painting layers, the curing period will be a few days and most slow-drying acrylic paints have a curing time of 30 days. For most paints wait at least 3 weeks to fully cure and harden the paint film.
Paint films of 1/4 inch thickness or more will take months and even years to fully cure. Also the physical properties of acrylics such as adhesion, hadness and clarity, will not fully develop if the paint film is not fully cured.
Golden Artist Colors, Inc.
I have written a whole article on ‘How long acrylic paint to cure? (Comprehensive answer)‘. You will learn more about curing, even the process acrylic paint goes through to dry and cure.
Many environmental factors can influence drying or curing time and stickiness. These are temperature, humidity, and airflow or ventilation. Artists can control these factors and use them to their advantage and reduce the stickiness of paintings. I have elaborated on each of them below as factors contributing to the stickiness of acrylic paint.
Poor ventilation or high airflow affects drying time causing stickiness
Poor ventilation can also cause, sticky paintings. Especially if you are using a canvas pad or an acrylic pad for painting. You might close the painting book after finishing the painting and it feels dry to hand. But after closing the book, there is poor ventilation, before the painting is fully cured. When you reopened the book and flip the pages, you will see the pages are tacky or stickier.
Moderate and steady airflow is the most favorable for drying. Keeping your paintings in a strong airflow or breeze can reduce the drying process and film formation. Thus it will cause the painting to be sticky and even, wrinkling or cracking of acrylic paint.
I have written a whole article about why acrylic paint is not drying. There you can find all the factors affecting drying time in more detail.
Keeping paintings in high humidity slows the drying process
Relative humidity represents the amount of water vapor in the air. It is expressed as a percentage of actual water vapor in the air to the maximum amount of water vapor that can be in the air at that temperature. When there is high humidity, it will feel wetter outside.
If the relative humidity is higher than 75% it will not be good for your painting. When there is more water vapor in the air, it will make it harder to evaporate water or solvent from the paint film, thus slowing the drying or curing process. The same can happen if a humidifier is in place. This can cause the stickiness of your acrylic painting.
Lower temperatures affect drying time causing stickiness
Lower temperatures, below 49oF (9oC) affect acrylic film formation. It will affect the ability of the acrylic polymer binder to bind the pigments together and form a paint film on the surface. Thus, it may cause stickiness, powdered films, and less adhesion to the surface.
The ideal temperature for proper film formation and drying would be 70 to 90oF during the drying or curing period.
Overheating your acrylic paint layers with a hairdryer or a heat gun can retard the film formation. It can burn the acrylic paint film and may cause bubbles. However, if you did not overdo it, it can help paint film to dry quickly.
Applying paint too thickly in layers causes stickiness
When you apply paint too thickly on a surface, it will take a long time to fully dry or cure. This is because thick layers of paint have more water inside the paint film, that needs to be evaporated. But you can adjust the environmental conditions to your advantage and speed up the drying process. As an example, you can use a hair drier to speed up the drying process.
If the painting is not fully dry, it may feel sticky or tacky. However, this does not limit artists from applying layers of paint when the underpainting is still dry or feels dry to the touch. If applied paint thickly, you need to allow it fully cure or dry for weeks or months to reduce the stickiness of the painting.
Also applying thick layers of paint on a less porous hard surface such as plastic, metal, or glass can take weeks or months to dry properly. Because these surfaces have no pores that allow water and solvent to escape paint film easily.
The quality of paints can cause stickiness
Sometimes the paint quality can affect stickiness, especially if you are mixing different quality paint. E. g., mixing craft quality paints with artist quality paints.
How to make acrylic paintings less sticky or tacky?
Now that you know a bunch of different reasons why your acrylic painting can be sticky, let’s explore the 10 easiest ways how to make your acrylic paintings less sticky or tacky.
1. Varnishing reduces stickiness of painting
This is so far the best option for sticky paintings. Varnish creates a barrier between the environment and the painting. It will protect your paintings from moisture and prevent yellowing with age. Most people use varnish as a solution for tacky or sticky paintings.
You can also use a sealer for this purpose. However, make sure you get a water-based sealer or varnish. Using oil-based varnish or sealers can ruin your paintings.
Before you varnish a painting, allow the painting to fully cure. As mentioned before, the curing time of acrylic paint is between 3 to 4 weeks. It will allow all the moisture to escape from the paint. Otherwise, moisture will be sealed in the painting with varnish or sealer and cause cloudiness of painting and poor adhesion of varnish.
Also if you have painted on a nonporous substrate such as glass, metal, or plastic, it will make solvents and water hard to escape from the painting unlike with a canvas. In this case, also, allow the paint to fully dry or cure for a month and then apply the varnish or the sealer.
Using a varnish or sealer will also make your paintings vibrant. It will give a better finishing to the painting. Matte spray sealers can also work well. One of the best sealers you can use is Krylon Satin Finish. The brand Krylon is one of the artists’ favorites. It is moisture-resistant and non-yellowing. Following is a link to buy it from Blick Art Materials: Krylon Satin Finish Spray Fixative
2. Allow the paint to fully cure
This is the simplest of all tips. If your paint sticks even after allowing it to dry overnight, the best thing is to let them cure for at least 3 to 4 weeks. Make sure you allow good ventilation in the curing period. If your painting is on a canvas pad or an art journal, keep the book open. You can also keep something below the painting to hold the painted page up, for better ventilation.
If you are painting on a canvas, do not stack paintings together before allowing them to fully cure. This will solve the sticking problem, even without varnishing the painting. Sometimes paintings will stop being sticky when fully cured, even without good ventilation. When the paint is cured, there is no reason for it to stick as there is no water or solvent left.
3. Use high-quality paints
Some acrylic paint brands and types are tackier than the other types. Mostly artist quality paint brands such as Liquitex and Golden are less tackier than craft-quality paint. It is always better to buy artist-quality paint for painting. It will make your painting vibrant and solve the sticking problem. Also, make sure you do not mix different quality paints. As an example, mixing craft quality paint with artist quality paint.
Below I have included links for the best deal to buy a Golden heavy body acrylic set and Liquitex professional heavy body acrylic set from Blick Art Materials. It will take your paintings to the next level.
4. Maintain proper environmental conditions
Always try to paint in a less humid environment. Painting in a very hot or cold environment reduces the drying of the paint and makes the paint sticky. Ideally, it is best if you can paint in an environment between 40 to 70 percent humidity. You can check the humidity at your painting place with a hygrometer.
You can also find the best humidity condition for the paint brand on the label of the paint tube. If you find that humidity is high in the area, use a dehumidifier or find a place with less humidity to paint.
Humidity is high after rain and it is best to avoid painting after the rain. Always paint on very dry surfaces. Especially if you are trying to paint on a moisture-absorbing surface such as wood, concrete, or a wall. Make sure these surfaces are fully dry, before applying a primer or paint.
Do not paint in a too hot or too cold environment. The best temperature for painting is between 70 to 90 degrees of Fahrenheit. Always check with your paint label for the best temperature for your paint. If you think you painted in a very cold environment, warm the room up to speed up the drying process.
Following is the best deal for a digital thermometer and humidity gauge from amazon. You can buy it with the following link: ThermoPro TP50 Digital Hygrometer Indoor Thermometer
5. Use wax paper in between paintings
You might have faced the tacky problem when storing paint, on top of each other. If you don’t like to varnish, you can use glassine paper in between the paintings. You can also use parchment paper or any wax paper between paintings when storing.
However as said before, allow good airflow until the painting is fully cured. It will not be a good idea to stack the paintings or pack them together during the drying or curing period. Following is a link to buy Glassine Art Paper from Blick Art Materials: Legion Interleaving Paper
6. Play around with the acrylic mediums
Some artists find, that when they change the mixing mediums for acrylics, the sticking problem solves. Play around with acrylic mediums. Try a matte medium with acrylics, instead of water. You can also try gloss mediums as well. These mediums support the acrylic polymer bonds, unlike water. You can add more mediums with less paint without breaking the polymer binder of acrylics.
Too much water can also affect the drying time. If you add more than 25% of water to the acrylic paint, the polymer bonds in acrylics will break. Thus acrylics will not dry into a plastic layer as they should. This can cause stickiness as the paint does not dry properly due to excess moisture.
Following is the link to an acrylic medium set from Blick Art Materials from the best artist brand Golden. Even though you may think you don’t need acrylic painting mediums now, you will need them to level up the look and the properties of your painting such as reducing the stickiness of paintings.
Stickiness can also happen if paint is contaminated with alcohol. Do not mix your paint with any products that have alcohol in it.
I have written a whole article about the 17 pros and cons of acrylic paint. You can find all the important aspects of acrylic paint there.
7. Allow the bottom painting layers to dry
When you are painting, always allow the bottom painting layers to dry, before applying the top paint layer. This way, moisture will not be trapped inside the painting layers below. This phenomenon is called ‘blocking’ meaning you are blocking the paint from drying.
Stickyness happen, when you apply too many coats of painting, too thickly, too quickly.
-Viktor
If you find yourself applying thick layers of painting and experience stickiness, consider applying paint thinly. Most of the time, if you are using an artist’s quality paint, you do not need to apply thick layers of paint unless you do a technique such as an impasto. Usually, the low-quality, student or craft-grade paint has this problem.
Artist’s quality paints are highly concentrated in pigments. You can apply very little paint and burnish the paint onto the canvas with a brush. Little paint goes a long way with high-quality paint. You can get artists’ quality paint from brands such as Golden, Liquitex, Winsor and Newton, and Amsterdam.
If you are already applied paint in thick layers, the solution will be to allow the paint to dry fully or cure. Allow the paint to cure for one month and see the results.
8. Have good ventilation in the painting
If you are using an art journal or canvas pads for painting ventilation becomes a problem. Most artists may not realize this. They will just close the canvas pad or the art journal after painting. Although the paint is dry to the touch, it may not be fully cured.
After painting, keep the painting book open for the night before closing them. This way you can prevent a lot of stickiness. Allowing the paint to cure for one month with good ventilation as mentioned before also helps.
In general, you should not keep the paintings in a closed environment, such as a box or a cupboard, or may store them in a stack, until they are fully cured. Your paintings need to have a good airflow or ventilation from front and back until it is fully cured. Also, remember to maintain proper temperature and humidity while allowing good airflow.
Never roll your paintings and store them before fully curing. It will not allow proper airflow and cause stickiness. But it may also cause the paint film to crack upon unrolling usually at a lower temperature.
9. Apply talcum powder on paintings
You can apply talcum powder to paintings to speed up the drying process. it will not feel sticky anymore. However, you need to do this on a finished painting. If you apply paint on top of powder, the paint may peel off. You can use a wide gesso brush or even around makeup brush to apply powder on top of the paintings.
If you do not like the look of powder on the painting, solutions will be to fully cure the painting and apply varnish to them. You can also use wax paper in between the paintings.
10. Prepare the surface before painting
Priming the canvas before painting is also important. However, you need to use a primer that is compatible with paint. Make sure you don’t use an oil-based primer. When using acrylic paint use gesso. Gesso will prevent the absorption of paint into canvas allowing us to get the best results with a little paint. It will also allow smooth paint application.
This will prevent sticky paint due to thick layers of paint. Additionally, gesso will help paint better stick to the canvas and prevent peeling. Make sure your canvas does not have any dust or grease. If there is any dust or grease, lightly sand the canvas and apply gesso. Do this even though the canvas is pre-primed with gesso. It will make the paint better adhere to the surface.
I wrote a whole article about what surfaces will acrylic paint not stick to and how to prepare almost any surface for painting. It will guide you to paint anything with acrylics and keep it off!
Conclusion
Although sticky or tacky acrylic paintings are annoying, there are many ways to fix them. The best way to fix is by varnishing or sealing the painting. You can also allow the paint to cure for one month. If you do not like both of these solutions, use wax paper in between the paintings to prevent stickiness. Always, prepare the surface well, paint in proper environmental conditions and use artist-quality acrylics. Following these steps will help you solve the problem easily.
I wrote a series of articles on common acrylic paint questions and answers: part 1 and part 2. So that you know answers to any acrylic paint problem like acrylic paint being sticky even before your face it!