How to thin acrylic paint the right way

Most artists will naturally thin acrylic paint with a liberal amount of tap water and they are happy with life. In most cases that works.

The problem is, when you are creating a high quality artwork using high quality materials you want to ensure your acrylic paint will be thinned out the right way, so that you do not end up with cracking, peeling or discoloration.

This means clean water, acrylic mediums or gels designed for use with acrylic paints.

What is acrylic paint and what is it made of?

Acrylic paint is a fast-drying paint made of pigment suspended in an acrylic polymer emulsion which basically means a type of plastic.

Acrylic paints are water-soluble, but become water-resistant when dry because the paint hardens into a plastic type layer.

How to thin acrylic paint without losing quality?

The best way to thin your acrylic paint is to slowly add a little bit of water until you have reached the desired consistency.

By slowly adding water, you will avoid over-thinning your paint which can cause cracking, peeling and other issues.

When thinning out your acrylic paint, always start with less water than you think you need. It is easier to add more water if needed than it is to try and thicken up your paint once it has been watered down too much.

Use a clean brush dipped in a little water to start with and then mix in with the acrylic paint and thin to the desired consistency.

If you use something like a dropper to add water then you may be adding more water to thin the acrylic paint than is actually needed.

bottle g11c1b07d8 640

Does the water used to thin acrylic paint need to be distilled water?

No, you can use regular tap water to thin your acrylic paint. However, if you are using hard water then it is best to use distilled water as this will help to prevent any build-up of minerals on your brush or in your paint.

If you don’t have access to distilled water, you can simply use bottled water or do as I do and use water from a filtered water container. I know some people like to boil their water and keep it handy in their artist’s studio for when they need it.

If you want to make your own distilled water, you can buy a gadget like the one below and make it as often as you need.

Do I need clean water for each color being thinned?

No, you can use the same water for all of your colors. I like to keep a cup or jar of water next to me when I am working so that I can easily dip my brush in and out as needed.

Though, for someone like me who is colorblind, I always worry that I may be changing the color of the paint that I am using so I tend to use clean water as often as possible.

I don’t want to risk green water tainting my yellow paint for example as I struggle to tell the difference between the two colors.

How do I know how much water to add when thinning acrylic paint?

The amount of water needed to thin acrylic paint will vary depending on the brand of paint and the desired consistency. A good rule of thumb is to start with less water than you think you need and then add more as needed until you achieve the desired consistency.

What do I do if I add too much water and my paint is too thin?

If you have added too much water and your paint is now too thin, you can try to add more paint to thicken it up or add a product called gel or paste medium to the acrylic paint which is specifically designed to thicken up paint.

modelling paste medium

Be careful when selecting the acrylic medium to add as some will make your acrylic paint glossy and some with make it matte. Be sure to use the one that matches your desired final result.

If you add clear gesso to acrylic paint it won’t actually thicken the paint, it just mixes in with the paint at the same consistency, so you just get more of the thinned out acrylic paint that you started with.

clear gesso

What are some other ways to thin acrylic paint?

In addition to adding water, you can also use a variety of other products to thin acrylic paint. These include:

– Acrylic mediums

– Gels

– Pastes

– Thinners (use water based thinners and not oil based)

Each of these products will thin your paint in different ways, so be sure to experiment with them until you find the one that works best for you and your project.

Do not thin acrylic paints with the following:

– Oil

– Varnish

– Turpentine

Mineral spirits

– Vaseline or other petroleum jellies

These products will not only thin your paint, but they will also change the color and consistency of your paint, so avoid using them if possible.

Why thin acrylic paint?

There are a few reasons why you might want to thin your paint. Maybe you’re trying to achieve a certain consistency for your project, or you want to be able to work with the paint in a more fluid way.

Whatever your reason, know that by following these tips on how to thin acrylic paint, you’ll be able to get the perfect consistency for your needs.

Are acrylic paints water based or solvent based?

Acrylic paints are water based, meaning they are soluble in water. However, they can also be thinned with other water-based products like water based lubricants and fluids but I would steer away from any product not designed for use with acrylic paints.

Reason being as it could have unplanned and unpredictable results in the short to long term such as cracking, fading and peeling.

The different methods of thinning acrylic paint

There are three main methods of thinning acrylic paint: adding water, using an acrylic medium, or diluting with a commercial flow improver.

1. Adding water to your acrylic paint is the most common and simplest way to achieve a thinner consistency. Start with small amounts of water and slowly add more until you reach the desired consistency. Be aware that adding too much water can cause your paint to lose its pigmentation, appearing lighter and lighter. So start with less and add more as needed.

2. Acrylic mediums are specialized products that can be added to your paint to change its properties. Mediums can be used to thicken or thin your paint, as well as alter the drying time, sheen, and other characteristics. When used for thinning acrylic paints , mediums will maintain the paint’s original properties while making it more fluid.

3. Acrylic glazes are thin, transparent layers of color that can be applied over a painting to alter the appearance. Glazes are typically made by mixing an acrylic paint with a glazing medium. This mixture is then applied over the desired area and left to dry. Glazes can be used to add depth and richness to a painting, or to change the color without affecting the underlying layer of paint.

4. Flow release is a special additive that can be added to your paint to help it flow more smoothly. Flow release is designed for use with airbrushes, but can also be added to conventional acrylic paints to achieve a thinner consistency.

An Acrylic Flow Release is a chemical that helps to reduce the surface tension of water, commonly referred to as a Surfactant. This improves the flow of acrylic paints. Below I have two examples, one from Golden and the other from Liquitex. I have never used Golden before but the reviews look good. Liquitex is my usual go to brand.

Golden Wetting Agent
Liquitex Acrylic medium

How to know if your paint is the right consistency?

The best way to know if your paint is the right consistency is to do a test patch on your surface first. This will help you to see how the paint flows and how it dries.

If you find that the paint is too thick, you can add more water or flow release until you achieve the desired consistency.

If the paint is too thin, you can add more paint or thicker mediums.

One thing I can say about acrylic paint is, wait until the layer is dry before applying a new layer and especially a new thinned out layers.

My experience has been that cracking will start to appear within months of the acrylic paint being fully dry.

So later the acrylic paint thin and add water a little at a time.

Tips for thinning your acrylic paint correctly:

– Use a container that has a pour spout to control the amount of thinner you’re adding to your paint.

– Add water or flow release slowly and mix thoroughly before adding more.

– Test your paint on a scrap piece of paper or canvas first.

– When thinning paint for airbrushing, use distilled water or an airbrush thinner designed specifically for acrylics.

Thinning your paint correctly will result in better flow and coverage, and ultimately a much nicer finished product. So take your time, experiment, and happy painting!

Troubleshooting when things go wrong

So what do you do if you have actually added too much water or medium? Do you throw that batch of acrylic paint out?

You could as acrylic is relatively inexpensive compared to oil paint but why be wasteful and why throw away good paint?

When things go wrong with thinning your acrylic paint too much, there are a couple things you can do to salvage the situation. Lucky for you, the troubleshooting steps are quick and simple.

If your paint is too thin and watery, add some gel medium or paste to thicken it up. You will have to experiment with how much to add. If you add too much, just keep adding more water until you get the consistency you want.

If your paint is too thick and pasty, add more water a little bit at a time until it reaches the desired consistency. It is always easier to thin out paint than it is to thicken it so take your time and don’t get frustrated.

These tips on how to thin acrylic paint will help you achieve the perfect consistency for your project.

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