Another technique to retard drying capitalizes on the permeability of acrylic gesso. After allowing the gesso layers to completely dry, attach the canvas to a temporary stretcher. Soak the back of the canvas with water, and/or attach wet rags or sponges to the back of the canvas. You have now created a stay-wet canvas. The dried gesso acts as a semi-permeable membrane, allowing water through to keep the paint moist. This technique allows you to paint in relatively thin glazes for hours with acrylics, but beware of some limitations. Cotton canvas may shrink, causing the stretcher to warp and make restretching a necessity. Also, the water may wash impurities out of the canvas and into the paint film. In severe cases this causes noticeable discoloration. These problems will be minimized or eliminated by using scoured (washed) cotton canvas. Or use polyester canvas, which is not dimensionally sensitive to water and does not contain the contaminants found in unwashed cotton canvas.
Does Acrylic Paint Wash Off?
Whether you’re a skilled artist or you’re just starting to dabble in using paint, then you’ve probably experimented with acrylic paint before. It’s versatile, easy to find, and relatively affordable compared to other mediums.
One of the most common questions that I’ve gotten regarding acrylic paint, though, is whether or not it’s waterproof or if it washes off easily.
If exposed to enough water, acrylic paint will wash off. Although acrylic paint is water-resistant it is not waterproof. The water could be from rain, washing painted fabrics in the laundry, or even just humidity in the air.
Thankfully, though, there are a number of methods that you can employ to help waterproof your paint and prevent it from washing off. While this may not be necessary for a small painting that’s sitting in a dry environment, it’s essential if you’re painting things that are exposed to outdoor elements or fabrics you plan on throwing in the washing machine.
Below, I’m going to explain why acrylic paint washes off and what you can do to prevent it.
Why Does Acrylic Paint Wash Off?
One of the biggest things that people forget when dealing with acrylic is that it’s a water-based paint. This means that the main liquid and compounds that help acrylic remain wet is water. This can be helpful if you accidentally spill the paint. As long as the paint is still wet, you can usually remove it using a damp rag. If you remember from science class, like dissolve like. This means water can dissolve water-based compounds, and oil can dissolve oil-based compounds.
Acrylic paint dries far quicker than oil paint because the water in the paint evaporates quicker than in its oil-based counterpart. This, in turn, makes it more forgiving if you make a mistake. You simply need to wait 30 minutes for the paint to dry before painting over your mistake with a fresh coat.
However, in other instances, acrylic’s proclivity to wash off fast can be problematic. For example, if you just painted an outdoor chair, the rain can come along and start washing it off the next day. Typically, once it dries, acrylic paint won’t wash off all in one go. Instead, it will slowly start to crack and chip, flaking off bit by bit. Ultimately, though, there will be little to no paint left on the surface.
What About Outdoor Acrylic Paint?
You may have come across outdoor acrylic paint at some point during your travels. Many first-time painters make the mistake of assuming that just because it’s an “outdoor paint,” that it’s also waterproof. Unfortunately, this is not the case (despite the misleading title of the paint).
Outdoor acrylic paint does have added compounds to make it water-resistant. However, it’s not fully waterproof. It won’t have a problem standing up to a light shower or a bit of evening dew, but eventually, even outdoor-rated acrylic paint will crack and peel just like the regular version.
TECHNICAL NOTES ON DRYING
Although acrylic paint tends to dry quickly, several techniques and additives can extend wet time. This Information Sheet discusses how acrylic paints cure and describes how that process can be controlled and manipulated to an artist”s advantage.
Water is Forced Out by Capillary Action
Acrylics dry as the vehicle that carries them, mostly composed of water, leaves the film. As water evaporates or is absorbed by the substrate, tiny acrylic polymer spheres are forced into ever closer contact. Eventually they are crowded so tightly that the spaces between them create capillary forces, and water is pulled from the paint film. This capillary action packs the acrylic spheres against one another in a honeycomb-like pattern, and they begin to form a continuous, cohesive film. As this occurs, the polymer spheres, composed of long chains of acrylic, actually deform and partially combine with one another in a process of film formation called coalescence.
The Two Drying Stages of Acrylics
The drying of acrylic paints occurs in two very different stages, hence drying times must be thought of in two different time frames. The first stage, a relatively short period of time, results in the formation of a skin over the surface of the paint. This is the time that it takes for acrylics to “dry to the touch”. At this point, the flow of water towards the surface is no longer sufficient to keep the paint film wet. Very thin films can feel dry within seconds, while thick films may take a full day or more to skin over.
The second stage of drying is the time for the entire thickness of the film to be thoroughly dry. That is, the time required for all of the water and solvent (used as freeze-thaw stabilizer and coalescent) to evaporate and leave the film. This is a most crucial time frame, as the ultimate physical properties, such as adhesion, hardness and clarity, do not fully develop until the film is near complete dryness. For very thin films, this time may be a few days, while films of 1/4 inch thickness or more will take months and even years to be completely dry.
Many artists are not aware of this more lengthy drying time. This is the reason that one may find that a rather thick layer of paint has not adhered to the surface when tested a day or two after application. This same layer of paint will also seem very soft. The skin may have dried sufficiently, but the paint in the center is still wet. Regarding development of clarity in gels and/or mediums, one can allow a painting to clear, store it away and later notice that it has become cloudy. The film may have only been partly cured, and is soft enough to allow moisture from the air to penetrate, turning it slightly milky again. Given enough time for more complete drying, these properties should improve dramatically.
INFLUENTIAL DRYING FACTORS
Temperature, humidity and airflow are environmental factors that influence the drying times of acrylic paint films. By controlling all of these factors, the artist can make use of their advantages.
Temperature
Ideally, the temperature should be around 70 to 90oF during the drying/curing process. Temperatures below 49oF (9oC) will not allow the polymer solids to properly coalesce to form a continuous film, and may result in film failure (cracking, adhesion failure, powdered film, etc.). Higher temperatures, like those reached with a hair drier or heat lamp, can speed drying times up significantly, but overheating can cause bubbling or burn the acrylic film. Likewise, lower temperatures will slow down the drying process and can be used to one”s advantage for increasing the working time of the acrylic paints.
Relative Humidity
Relative humidity in excess of 75% will slow the evaporation of water from the surface, slowing down the drying process. Temperatures of 70 to 85oF and humidity under 75% are ideal for drying.
Air Flow
While a moderate and steady airflow in the drying area is favorable for thorough drying, a strong breeze, especially one directly on the paint surface, can cause film formation failure, such as cracking and/or wrinkling.
DRYING EFFECTS
Utilizing the Quick-Drying Tendencies
The naturally quick drying time of acrylics can also be a great benefit. Many of the most successful uses of acrylic paint come from people taking advantage of this property, which allows for painting over almost immediately. Unique acrylic glazing techniques, hard-edged applications and quick manipulation of the painting surface would not be possible without these very rapid drying properties.
Application of Additional Layers of Acrylic Paint
There are no limitations on applying additional acrylic paint layers. That is, an artist can apply acrylic paints while the underpainting is still wet, just skinned over, or has dried for several years. If one is going to apply oils over an acrylic underpainting, then a proper curing time should be allowed to be sure the acrylics are completely dry. For thin films on canvas, this can be 1 to 3 days. Thicker films on less porous supports like masonite may take several weeks to dry sufficiently to ensure proper adhesion.
Varnishing Considerations
For varnishing, it is best to wait until a painting is completely dry. Otherwise, an excessive level of water and/or solvent may be trapped, which could result in clouding or poor initial adhesion of the varnish. This is more important when the varnish forms a relatively tight, non-permeable film, such as is the case with GOLDEN MSA Varnish. When using more permeable varnishes, such as GOLDEN Polymer Varnish, this is less crucial.
Another critical element to consider when varnishing is the substrate. A canvas will allow trapped moisture, retarders and other additives to escape, while metal, masonite or plywood make this migration difficult, and can influence adhesion of the varnish layer. In extreme cases, it can cause delamination or cracking of the varnish. (Refer to the GOLDEN Varnish Information Sheet for a more through understanding of these properties). Generally, the painting should not feel cool, excessively soft or tacky. All of these symptoms indicate an uncured acrylic paint film.
Acrylic Paint and Rain
Acrylic paints are water-soluble, meaning they can be removed from a surface by water. This may take days, weeks, or years, but eventually, the acrylic paint won’t be what it was meant to be.
Things may not entirely fall off of your canvas or woodwork. However, acrylic paint exposed to the elements may chip or come off, but this will be because of a combination of factors.
If you want to paint something outside and know that it might get wet in the rain or snow (or if you’re just curious), then you’ll want to make sure your outdoor acrylic paint is waterproofed first. If not, and the weather turns suddenly rainy while you’re painting on your piece, you’ll have some unexpected results when the moisture hits your painting surface!
The Elements Affect Your Acrylics in Many Ways
It’s not just the rain, either!
When those spring showers come through, there may not be much left! Imagine a garbage can or compost pin decorated with colorful acrylic paint. The heat may make the acrylic paint heat up in the hot summer, leaving it a little rubbery. Then, the wind of the fall may blow those pieces away. Whatever’s left may freeze up and chip by the winter.
In addition, acrylic colors will likely fade in the sun and rain. This is why it’s recommended that you use other paints for outdoor projects or even match the paints up to the texture you’re working with. Glass paint is different from wood paint, which is different from ceramic paint. Pick the paint that matches your project best!
It Also Depends on the Surface of Your Artwork
It also depends on the surface you have your acrylic paint on.
Acrylic paint can be used on almost any surface, including glass, so it’s great for indoor projects. However, it doesn’t absorb into porous materials like wood and canvas that well. So, if you use acrylics outside on a surface that wears out quickly (say, if you’re painting your house), chances are that there will be some wear left behind after it rains.
Not that you’d try to paint your house with acrylics! However, this still is important when painting other things. Wood, canvas, outdoor furniture – no matter what you’re painting, the acrylic paint may stay for a while and not be washed away immediately. However, constant wear and tear will eventually affect the paint, which may begin to chip. Additionally, colors will definitely fade.
However, acrylic isn’t the worst to paint with for outdoor surfaces. Watercolors just won’t work, and oil paints are an even worse option.
In fact, as compared to oil paints, acrylics are less likely to fade over time (but will still fade with constant exposure to elements). They also have a more consistent texture and color throughout the project. You won’t have to worry about things like streaks or unevenness.
Use acrylics on projects that don’t get too much direct sunlight for the best results. If your painting will be exposed to bright sunlight over an extended period, consider using an alkyd-based paint instead of an acrylic one—it will last longer under those conditions.
How To Protect Your Acrylic Paint in Outdoor Conditions
Acrylic paint is water soluble when wet but becomes waterproof when dry. This means that while it can withstand a bit of rain or moisture, it will eventually wash away. However, there are some tricks you can use to make your acrylic paint more resistant to the elements.
Using a Sealant To Protect Your Work
To make acrylic paint more water resistant, you can apply a sealant.
Seals are easy to use and can be applied with a brush or roller. They come in various forms—some have texture, while others are very smooth—and they’re available at most hardware stores. If you decide to use your own sealer formula, ensure it’s tested for safety and won’t harm your surface.
Sealants can be applied over acrylic paints or on their own. However, when using them over existing paint surfaces (such as walls), it’s essential to test them first to see if they’ll cause damage or discoloration. You can do this by testing the sealant on an inconspicuous area first before applying it everywhere else.
Using Exterior Paints for Outdoor Work
Using outdoor exterior paint (think Behr or Sherwin-William) will make any outdoor artwork nearly waterproof because it factors in things like humidity. Acrylic paint can often be washed off with a bit of soap, elbow grease, and warm water (or enough rain), but if you want to ensure that your artwork is protected from rain or other moisture, use an exterior acrylic or oil-based paint instead of the regular kind.
If you don’t have access to these products at your local hardware store, plenty of websites will sell them directly to you.
Priming Your Surface Before Work Begins
Priming is the first layer of paint you put on a surface. The purpose of priming is to create an even surface for your paint and help prevent cracking or peeling later in time. When painting a surface, it’s essential to prime the area before applying the finish coat.
Priming also makes your finished product more durable by creating an invisible barrier between your new color and whatever lies beneath it—this helps prevent damage or wear that could cause cracks in your newly painted artwork.
Final Words
To conclude, due to wind, rain, sun, and weather exposure, acrylic paint will fade over time. It’s important to remember that the more you use your acrylics, the faster they will fade.
Things may not wash off as if you used watercolor or finger paint, but they’ll chip away over time nonetheless.
Related posts:
- Can You Be Allergic To Acrylic Paint?
- Does Acrylic Paint Fade or Melt in the Sun?
- How To Tell if Your Acrylic Paint is Moldy?
- How To Thicken Your Acrylic Paint for Dotting
