Acrylic paint is water-based paint and this is perhaps the main reason it is a popular choice for many. Being water-based, it comes with lots of good qualities that were missing in earlier paints. Water-based translates to less time waiting for paint to dry, less toxicity, and more affordability. You can even wash off acrylic paint with just water while still wet.
On the flip side, the staying power of paint that washes off with water is likely to be questioned when the painted surface is faced with moist conditions. This is especially true for outdoor painted surfaces exposed to long-term wetness from rain, snow, and humidity.
So, is acrylic paint waterproof? Although acrylic paint is water-soluble when wet, as it is water-based, it actually becomes water-resistant when dry. However, it is not entirely waterproof and should be sealed with varnish or lacquer to avoid being ruined by humid or moist conditions.
This, however, should not deter you from considering acrylic paint as an option for outdoor crafts and those that need frequent washing. Read on to learn more about how to make acrylic paint waterproof.
Should You Waterproof Acrylic Paint?
Acrylic paint is the preferred finish by many home crafters and professionals, be it canvas painters, paper artists, or woodworkers. It offers a smooth application, a speedy drying process, and easy post-painting cleanup. It happens to be an inexpensive option too.
The beauty of working with acrylic paint, however, is its versatility. It is compatible with a wide range of surfaces: wood, paper, ceramics, fabrics, etc.
But acrylic paint is a water-based paint which leaves many confused about its protective capabilities against water damage. Does it form a solid waterproof polymer layer after complete drying?
Well, acrylic paints are pigments suspended in water-soluble acrylic polymers. This is the reason acrylic paints dry quickly. Being water-based, the water molecules separate from the suspension rapidly through evaporation, especially when temperatures are high.
What remains is a plastic-like acrylic polymer film that is water-resistant. It is pretty tough, and even though the wet acrylic paint is washable by water, once dry, this coat can’t be dissolved by plain water. You’ll need the help of detergents, or other cleaning agents, and even some abrasion.
Therefore, it is safe to say that you do not need to waterproof acrylic paint for indoor use in dry areas. Occasional wetness like water splashes or just damp wiping the surface cannot ruin the paint.
While this coat cannot be washed off with water alone, it is not entirely waterproof. If left in contact with water for an extended period, it absorbs its molecules through the tiny pores, and eventually, the paint will start to crack, peel, or chip.
To avoid ruining your project and wasting your hard work, waterproofing is necessary on acrylic painted surfaces in the outdoors or near moist environments.
Now, there are various kinds of acrylic paints: artists grade, craft grade, and outdoor acrylic paints. Outdoor acrylic paint is designed for exterior surfaces, which raise this other questions.
Is Outdoor Acrylic Paint Waterproof?
No, outdoor acrylic paint is not waterproof. It can be ruined by water in the long run. It is weather-resistant, though.
This paint differs from standard acrylic paint because of its ability to tolerate weathering. It’s primarily made to be used for exterior applications.
It is formulated to resist fading caused by ultraviolet light from the sun. It is also engineered to contract and expand accordingly to stay adhered to the surface, even in changing temperatures.
Outdoor acrylic paint is also tougher and has better water resistance but it still isn’t entirely waterproof.
4 Ways To Waterproof Acrylic Paint
To waterproof your acrylic paint, you will need to apply sealants. Applying a sealer after the paint dries will preserve it for a long time. You can apply sealants on either interior or exterior acrylic painted surfaces by spraying or brushing them on.
Sealants create a waterproof barrier that protects your acrylic painted surface from moisture penetration. In addition, they also brighten the flat chalky appearance of acrylic paint and may deter fading if made for archival purposes as well.
There are a couple of products you can use for waterproofing your acrylic paints. Your choice depends on whether you are waterproofing a canvas painting or a wooden item.
Vanish is the go-to sealer for all types of acrylic paint, paintings, crafts, and even furniture. There are two types of vanishes; acrylic resin and acrylic polymer varnish.
Acrylic resin varnish is glossier and smoother compared to acrylic polymer varnish. So if you want a shinier appearance, the resin varnish will be sufficient. Polycrylic varnishes are popular finishes for waterproofing acrylic paint.
Using spray varnish is easy, and it covers expansive surfaces quickly, but you will need to spray several layers for proper coverage. Brushing on varnish takes time compared to spraying, but its results are more accurate, as every inch is covered.
Vanishes when dry form a hard shell that resists scratches without yellowing. Besides waterproofing your paint, they also protect painted surfaces from harsh sun rays and dirt.
Polyurethane is a tough clear sealant. There are two types of polyurethane; oil-based and water-based and you can use either of these over acrylic paint.
Water-based polyurethane is popular because of its low odor and less toxicity. It also dries way faster than the oil-based version. However, oil-based polyurethane forms a superior protective coating.
Apart from waterproofing, Polyurethane finishes enhance the surface appearance, making it glossy and allowing the acrylic paint color to pop. However, polyurethane is sensitive to heat and chemicals. So it is advisable not to use it on pieces that will be exposed to high heat.
Lacquer forms a waterproof coating that protects acrylic paint. It is durable, though thinner compared to other sealants like Polyurethane.
Paints coated with lacquer have a beautiful appearance that does not form a yellow tint like other finishes. It is perfect for wood and metals as well.
Shellac is a natural product made from combining female lac bugs with denatured alcohol. Consequently, it should be applied very thinly and cautiously, preferably sprayed so as not to dissolve and lift the acrylic paint below. It is great for wooden pieces.
How To Waterproof Acrylic Paint On Different Surfaces
Applying sealants is not a complicated process; all you need to do is to follow the manufacturer’s instructions. Generally, a sealant is applied when the acrylic paint has dried fully; if not, wait longer. Ensure the surface is clean and free from dust. You can wipe it with a lint-free dry towel.
Afterward, apply the first coat using a broad base brush and give it time to dry. You can opt to use an aerosol can or a spray gun. Upon confirming that the first layer is dry, apply the second layer if necessary. Some sealants do with just one coat and others two. But rarely would you need more than that.
Allow the sealant to dry. Avoid feeling the layer all the time. It leaves ugly fingerprint impressions on your surface. Just follow the manufacturer’s recommended time.
Acrylic paints are quite popular with canvas painting since they are less fussy than oil paints and dry faster. Priming the canvas before painting with acrylics will help seal your painting even more.
You can use any of these finishes for waterproofing; a waterproof glaze, polycrylic finish, acrylic resin, or polymer varnishes.
Apply these with a brush or spray. As long as the painting is completely cured, either will work. Sprays provide a pristine flawless coat free of brush marks.
A tough sealant is ideal for acrylic-painted furniture. Polyurethane, lacquer, or varnish are all great options for waterproofing acrylic paint on wood. Adequate preparation of your wood before painting and sealing is necessary for best results.
Applying double coats of sealant is suitable for guaranteed protection, leaving ample drying time(usually 24 hours) between coats before adding the second layer. This will ensure that both coats are fully cured.
However, wood is a bit more finicky when it comes to painting and sealing due to its porosity, so we have a whole other article for you to take a look at on how to seal acrylic paint on wood.
Acrylic paint adheres well on metals if well prepped and is commonly used on autobodies. But still, you must waterproof your paint to make it stay longer. Polymer varnishes, acrylic varnishes, and enamel-based varnishes are the best for metal. One layer of vanish is just enough.
It is not uncommon to find glassware decorated with acrylic paint. And because these are washed so often, waterproofing the glass is quintessential.
Varnish is a common medium to use for sealing acrylic paint on glass. However, its drying time is long. It takes almost three weeks. To hasten the drying process, you may put your glass in an oven at 350°F for about half an hour.
Masonite is made up of compressed layers of wood fibers. It is naturally water-resistant, but waterproofing is still crucial because sometimes installed fasteners expose some parts of masonite. Those parts absorb moisture, making them expand and swell. Lacquer-based sealers bond adequately with masonite.