How To Make An Acrylic Painting Waterproof

Michael Daly
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What Is Acrylic Paint?

It is a modern pigment-based water-based paint. It can also be used in place of oil paint, if painting on a budget.

It is a durable paint which is applied in layers on a surface, bonding with it, and the acrylic paint is usually water-based, so water is present when applied. Water provides the solvent action, dissolving the paint for it to flow and adhere to the surface, and although the water is thus essential for the painting, it is a disadvantage when painting on a water surface such as a lake. The drawback is that the paint will not work well on a smooth, flat surface as it will be absorbed by such a surface. Acrylics are best used to paint over a rough surface that will offer some texture and access for the paint to adhere, and maybe even protect the layer beneath.

Why Should I Waterproof My Painting?

Acrylic paint dries completely transparent, but if it’s not sealed, it can lose pigment over time.

Acrylic paints are water-soluble. So as the time passes, they will start reacting with the water vapor in the air and turn from transparent to milky and eventually to whitish or yellowish.

This process is known as weathering.

The air in our homes tends to be more humid than in the outdoors due to the heaters, humidity of showers, and activity of other people.

Closing the windows doesn’t help much because hot air rises. So your paintings are subjected to the most humidity in the top floors of your house.

Even if you take extra care to make your paintings watertight, after a time the weathering process will still occur. So it’s a good idea to seal the finished painting with a varnish as soon as possible.

Painted surfaces exposed to light will fade from UV damage. This goes for both acrylics and oil paintings.

Sunshine makes white surfaces more transparent by boosting the pigment, and while the color remains the same, your picture looks “whiter.”

If your acrylic painting is unframed, the process of UV damage is accelerated.

Why Would Varnishing Help?

When you varnish your acrylic painting, it doesn’t seal the paint. It seals the top layer of paint to the surface of the paper, preventing water from getting in, anything else from penetrating, and the oils on your fingers from spoiling the surface.

This may or may not be a huge deal. I use Acrylic Gesso for my surface layer (on top of which I “paint”), which already has acrylics and a special surface texture that prevents the paint from absorbing into it the way it would on a smooth paper surface, and therefore makes it easier to clean up after, and I’ve never had a problem with any water staining, tarnishing, etc.

The most common use for varnishing after acrylic paintings, as I mentioned above, is to protect them from water. Any time my daughter spills water on my paintings, I can take it right back to the sink, where it happily washes away.

I also use this technique for outdoor paintings.

What Makes The Varnish Water-Resistant?

First, we need to understand the different types of varnishes. There are the “traditional” water-soluble oil-based varnishes available at any art store. There are also water-soluble acrylic paints.

As you can see, the traditional oil varnishes are more water-resistant than the acrylic paint. So to emphasize the difference, I decided to try the two type of varnishes on a similar painting.

I created a simple painting in acrylic on canvas. I left the back unfinished so that I could easily spray paint it black. Then I decided to cover it with an oil-based varnish and a water based varnish. As you can see from the picture, the traditional varnish is more transparent while the acrylic varnish is more translucent.

The reason for that difference is that the traditional varnish contains a pigment that works as the color carrier. The acrylic varnish, on the other hand, consists only of a resin and the solvent in which it’s suspended.

How Do I Varnish My Painting?

Painting, varnishing, and sealing your acrylic painting is a simple but important step towards making your artwork more durable. Acrylic paints can be really vulnerable to water, especially the light colors. So to protect your work from accidental spills or the slightest bit of moisture, the first thing you need to do is varnish your painting.

There are two methods you can use to protect your art. One of them is the spray painting, which is fairly straightforward and inexpensive. The other is an art varnish, and if you want your art to achieve a smooth and glossy finish, I recommend this process instead.

The truth is that having an art varnish on any painting will make it look professional and will also seal off all the small cracks and crevices, which otherwise could allow water and external elements to damage your art. But if that’s not enough, the varnish also creates a glossy finish, which is very attractive and can raise the overall value of your artwork as well.

When you varnish your painting, you’re essentially creating a waterproof barrier, and the paint underneath will still be intact, vibrant, and last longer. Also, if your painting is already framed, the varnish makes a perfect seal and will keep the artwork clean for a long time.

Waterproofing Acrylic On Canvas

When I discovered acrylic paints I was hooked. They are so easy to use. And with a variety of textures, colors, and finishes, you can get just about any kind of surface you want.

One of the biggest problems, though, comes if you want to try your own hand at water coloring techniques. Acrylic is not watercolor, and if you try to use the same techniques, you’ll create big problems.

While I’ve never had a desire to do it, you can use a wet palette while painting with watercolors. Acrylic paints, though, are made with synthetic binders that will wick up water like a sponge. While this will make a nice, moist spot in your painting palette, it will also destroy your painting.

The traditional way to solve this problem is to seal your painting with a layer of varnish or a fixative to ensure that the acrylic won’t soak up water. Unfortunately, both of these solutions will also stop you from being able to add watercolor washes later on. This is a problem if you want to change the color of your painting or add highlights.

Waterproofing Acrylic On Metal

A common problem with outdoor acrylic paintings is that their image will warp and crack as the paint dries. The reason underlying this is high humidity levels.

If you have paintings that are cracked and warping from humidity, there is no need to worry. This can be easily prevented by waterproofing acrylic on metal using epoxies.

Waterproofing Acrylic On Wood

Acrylic on wood doesn't require a great deal of sealing. This can be done by using a delicate spray sealer and some tack cloth to remove the dust.

If you're planning on leaving the work not exhibited, it's best to treat the surface with a transparent varnish. Displaying the work is clear enough.

Waterproofing Acrylic On Masonite

Good old masonite is great for acrylic paintings. Masonite takes acrylic well, and when covered with several coats of varnish you get a painting that is durable and not affected by humidity.

Construct your painting on masonite. Use any other material you like but masonite is cheap, lightweight, and works well.

Place your masonite on a sturdy surface if you don't want it to move around when you are painting. Be sure to put it on a surface that is open to the air so excess moisture can evaporate easily. If your surface is other than flat, use a level to ensure that the surface is level between all sides of the masonite.

If you are painting a portrait, you can arrange wood blocks around the portrait to prop it up and ensure that the angle is level.

Apply a layer of gesso on top so the paint will not soak into the surface and cause buckling of your painting.

When you are done painting, you can cover the painting with two more layers of gesso and varnish to waterproof it.

Waterproofing Acrylic On MDF

I'm trying to water seal acrylic paint on a MDF frame. It's an outdoor piece. Anyone have any pointers on what should I do? I'm tempted to varnish the frame to give it extra strength.


This is a common question on any acrylic painting forums and there are one of two schools of thought on it:

Some people swear that using acrylic mediums like GAC 100 are the only way to waterproof the paint and that varnishes will never work and just lead to more problems. I've also heard that these mediums are actually a no-no as well. So the first school of thought is basically:

Don't use mediums and varnishes will work on their own.

I've read of people using Leather England lacquer and I find that interesting because it's an acrylic medium that's not supposed to work. Another acrylic medium that I know of, which is used for coating small wooden items I might add, is Zinsser 111.

Personally, I don't understand why you couldn't use an acrylic medium such as gesso, GAC 100, or even a matte medium since they are all acrylic in nature and should be safe to use on acrylic paint. I believe that the myth was started by well-meaning people who wanted to make sure that you didn't use anything that would potentially contaminate the acrylic paint.

Waterproofing Acrylic On Plastic

Acrylic paints and spray paints can be used to paint and decorate almost anything. But you’ll have to be careful if you plan on using these paints for items that will be exposed to liquid. plastic and acrylic will warp or dissolve if you place it in water.

However, if you want to paint a plastic box that you will place in sinks or the bathroom, you can still use these paints. You just have to make a small investment and waterproof the acrylic before painting on the plastic box.

Only a few drops of acrylic paint are needed to create designs and images on plastic. Just like painting on paper, you can make layers and create different shades by applying paint on the same area carefully.

Like most of the paints sold in the market, acrylic paints have pigments that are mixed with a solvent to keep them from drying as fast. Once it dries, they are painted on another surface. If you are using acrylic or paint spray on plastic items, the solvent will cause the plastic to become soft and sag.

The trick to making acrylic paint waterproof is to add latex paint to the acrylic paint. This will make a solution that both paint and plastic won’t dissolve.

Waterproofing Acrylic On Glass

A large body of artwork today is viewed on monitors and projected. Such as murals and other wall art in public spaces and homes. Images are beyond the reach of the human hand

Most are painted with acrylics on glass. This has several advantages and disadvantages that dominate the choice of medium.

The most significant advantage is the ability to paint on glass. It is cleaner than paint on a wall or other mediums. It is much easier to transport and install. In addition, it is more natural than a painting on canvas. It is easier to discover edge of the painting and more reminiscent of a painting on a wall.

The main disadvantage is that acrylic paints are not waterproof. Water absorbs into acrylic paintings and accelerates decay.

If you think you can use a glass painting that may be shown in public spaces, museums, galleries or public halls, you must add a protective layer to your painting to prevent it from decaying.

Do I Need Special Tools To Apply The Varnish?

No. Any cheap brush will do – but I'd recommend getting an extra fine artists brush as it will give you more control. The other option is to use a sponge. Sponge painting is a very popular method. If using a brush or sponge, any craft store will have flat brushes. Do not use a foam brush as it will leave brush marks.

Will The Varnish Ruin My Brush?

If you’re an acrylic painter, you may wonder if varnishing your paintings will ruin your brushes.

This is something that we have all asked ourselves because it seems like a good idea to use a varnish finish so that you can be carefree when transporting and storing your paintings.

This common belief that you should keep your paintings unvarnished may be true if you are planning to sell your paintings at an art show, in a gallery, or at a price that has a big number after the dollar sign.

Varnishing your paintings would drive away most serious collectors, but for us, it’s great because we only sell our paintings to family and friends anyway.

Here are some pointers to help you keep the varnish off of your brushes while making your paintings water resistant without needing to leave them unfinished.

{1}. Start your acrylic painting with very thin paint. Beginners tend to keep adding more paint even until the very end. This is very bad because it makes the piece very thick and difficult to varnish.
{2}. To thin it out, spread it with a palette knife (or a wooden spoon) over a smooth surface like an old cardboard box or simply a piece of paper. The thinned paint will dry in thin layers, meaning less varnishing and easier painting later on.

Types Of Varnishes For Acrylics

There are several types of varnishes for acrylics; however before picking a varnish you must consider several things. The artist’s goal for this piece should be a major factor in the choice of varnish. In addition to this, the medium also determines the type of varnish that should be used. Do you have an image that looks as if it is floating in the picture? A type of varnish can be used that will enhance the effect in a noticeable manner.

The other thing that you need to realize is that acrylic varnishes come in several forms. They can be matt, glossy, or satin. They can even have a glossy surface which is not really intended to be a varnish. A clear gloss varnish could create something called an aniline when exposed to light. The common types of varnish used on acrylics include:

Matt Varnish-Matte varnish is extremely suitable for acrylic paintings as it is the most water resistant; it is best to use it on a mat finish.

Modelling Varnish -If you want to clear details out of gloss varnishes, you must choose this medium. This medium can be spread over a painted surface within 15 minutes.

Something To Consider

Acrylic painting is a wonderful medium and can create some very stunning paintings.

However, acrylic paintings can be very easily ruined by water.

The colors will bleed, and when it dries, it forms a white residue on the painting. It is not something you can clean off.

Once you’ve created your masterpiece, you want to keep it looking it’s best for as long as possible.

You can protect your acrylic paint from water damage by using a sealant to coat it for protection.

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