What is Acrylic Paint Flow Improver? Should You Use It?

Flow improvers are a type of additive created to specifically work with acrylic paints.

Those who paint with acrylics can attest that the viscosity of these paints is nearly as thick as oils.

But unlike oils, acrylic paint is water soluble which means that it will thin when it is mixed with water. And, since it is water based, it dries quickly when exposed to air.

This can make for an inconsistent flow and texture while painting. 

What is acrylic paint flow improver? Flow improver, also known as flow aid, is an additive used to break up the surface tension present in the water of acrylic paint. The aim is to chemically change the consistency of the paint with no effect on the color or finish composition.

Flow improver provides artists with a much smoother, silkier stroke as opposed to the stickiness associated with traditional acrylic paint.

Flow improver can be intermixed along with any type of water-soluble paint, ink or dye, or medium.

(I explain all about mediums here – what they are, different types, how to use them, and what my favorites are.)

When it comes down to creating a variety of different cool effects or extraordinary textures with acrylic paint, mediums and additives such as flow improvers are indispensable.

Using flow improver as an essential paint tool assists in transforming your standard pieces into versatile works of art.

If you’re just getting into painting miniatures or are new to acrylics, you likely have questions about other painting-related issues and tools as well. 

Be sure to check out my miniature painting page to learn various tips, view recommended products and tools, and discover a huge variety of other topics (more than 50 articles in all). 

Also, for all you budding miniature painters out there, I can’t recommend my latest book, The Miniature Painting Level Up Guide, enough. 

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It’s easy to feel overwhelmed by all the tools and various techniques everyone’s always talking about. In the book, I walk you through:

• What you really need and what you can do without.
• Actually getting started.
• How to build upon your skills and move to advanced gear and techniques.
• Where to find the best miniatures and which pros to follow on social media.
• So much more!

Everything included in the book is exactly what I wish I had known when I was first getting started. It really is a must-have for beginners and those with a few minis already under their belt!

Do You Need To Dilute Flow Improver?

Flow improver additives are specifically made to break down acrylic paint. Even top-quality acrylics, like Vallejo Basic Paint Set, will benefit from a flow aid.

They have the unique capability of getting the paint to a stain level if you so choose, which is even thinner than that of a wash (find more on washes and shades here).

This range of available consistencies allows for a broad scope of options and techniques to be explored with acrylic paint. 

How the flow improvers are used is dependent upon the manufacturing company.

With certain flow aid additives, e.g., Liquitex Flow Aid, they need to be diluted with water, but there are some that can be used straight from the bottle.

Liquitex Flow Aid recommends that you dilute 20 parts of water with 1 part of the flow aid for a successful result.

There are brands that come with acrylic polymer emulsions which is the same binding agent within the paint allowing it to be added until the desired consistency has been achieved. 

Why Would I Use Flow Improver?

There comes a time when a budding new painter comes to squeeze a bit of acrylic paint out of its tube as a beginner and has a shock over the incredible thickness of the paint.

This can cause a lot of beginning acrylic painters to abandon this paint medium. 

Before you attempt to use acrylic paints, they have to be prepared and thinned which is the most difficult part of this medium’s process.

Without understanding, it can be tough to accomplish the viscosity and shade that you are hoping to achieve. This is where the flow improver comes in.

The variety of different mediums and additives that can completely change the finished appearance of a piece of work is what draws artists to acrylic paint over that of oils. 

One such additive is flow improver which is noted to be a product you should use for breaking down acrylic paint as opposed to thinning with water. 

With flow improver, acrylic paint begins to flow in a much smoother and silkier fashion with the brush.

A benefit of using flow improver over water is that there is no marked reduction of the strength of the color.

This is even possible on the smallest of details with no signs of drying or clumping. (How long does it take acrylic paint to dry when no additives are used? Find out here.)

Water alone cannot reduce the surface tension of the paint as flow improver can.

A flow improver makes painting with acrylics the joyful experience that it was meant to be.

It should be introduced to the beginning painter as a part of a ‘starter set’ of sorts in order to show them how wonderful the experience actually is.

Putting together a “starter set” can be tough. There are just so many choices when it comes to gear! Take a look at the essentials and a few bonus “fun toys” on my recommended gear page.

Summing up the benefits of using flow improver right from the start:

• Flow improver allows ease of flow with the paintbrush with no sense of struggle to force the brush along the surface. The paint glides smoothly and freely.
• Flow improver works with the chemistry of the paint to change the consistency without affecting the color. The paint remains rich and vibrant.
• Acrylic paint dries very quickly. With flow improver, drying time increases, allowing more freedom during the painting process.

Some artists will combine a blend of flow improver with retarder when they need to cover a larger space.

The flow improver assists the paint in spreading while the retarder keeps it ‘open’ or slows down the drying process as it is being spread.

Why Not Simply Use Water?

Pouring mediums and additives are used to make acrylic paints flow and pour much more smoothly and freely.

They act as binders and diluting agents. These mediums/additives give acrylic paint smoother flow and assist the paint with a blend of colors to act in a more uniform fashion. 

The integrity is improved as the paint is able to dry with no type of cracking, fading, or separating,

These mediums/additives, e.g., flow improvers, essentially make the acrylic paint much easier to manipulate.

Using water to thin the acrylics is obviously easy and cost effective in order to make the paint easier to work with when you’re on a budget.

But there are big drawbacks to using water:

• The color will be diluted causing the vibrancy of the paint to be lost when translated onto the canvas.
• The binding agents will also be diluted by the water in the paint which means that they aren’t going to stick to the canvas, not to mention harder surfaces such as wood.
• Water is not able to bind completely with paint resulting in a consistency that is uneven when you begin to paint. 
• You may see flaking and lifting off the canvas as the paints dry or layers that won’t adhere to each other. 
• Watering down a paint also affects the binders, pigments, and finish once the piece is dry.

Of course, a lot will depend on the quality of your paints.

You want to use the highest quality possible. See what made my list of the best of the best miniature paint sets to help you choose wisely.

When This Is Still Not Your Shade

Many times, an artist will feverishly stroke their inspiration out onto the canvas with their mistake being that they don’t pay any attention to their process.

In so doing, they ultimately have a result that they are not happy with.

This isn’t necessarily a problem if you’re working casually, but a professional who is on the clock doesn’t have time for errors.

It’s always smart to step back and assess the process you’re using before you progress into your work, which will prevent you from thoughtlessly blending countless mediums to thin acrylics, doing much more harm to your process than good.

If you’re not obtaining the perfect shade you were hoping for, you should mix different colors together as opposed to simply pouring in various thinning mediums.

There are also other tricks you can employ to get the acrylic viscosity and shade where you want them.

• Primed layer.  If you make your canvas or want to try the thinned acrylic on a nontraditional piece of wood or maybe metal, prime the surface prior to using it with something such as gesso, which is an optimal base for acrylic-based pieces.

This is especially good for acrylic that has been thinned to a stain or even a wash.

This will aid you in achieving the shade and bring out the depth of color that acrylic paint is able to give over that of watercolor or oils.

Without priming and on a non-traditional surface, the paint tends to get sucked up and you won’t see the results that you need. 

• Change Your Brush. The brush is extremely important with acrylics (here are some of my favorite brushes). As opposed to the standard #6 brush for the very first wash, you should go with a much wider option by at least a couple inches. Foam is always a good, inexpensive choice for the first wash unless you will be doing multi-layers.

Want a sneak peak at my all-time favorite brushes?

This synthetic set has 10 brushes in a variety of shapes and sizes – perfect for all kinds of painting tasks, and they are quite inexpensive!

If I had to pick my absolute favorite brush, it would definitely be the Rafael Sable 8404.

It holds paint really well, is capable of producing fine lines and detail work, and is the brush you need to bring your work to the next level.

There is a vast array of different methods for acrylic thinning arising in the recent trends. Feel free to try your hand at what feels comfortable for you and your specific needs.

Ultimately, you need to enjoy your process and there are products out there that make that easier!

You’ll find more thinning tips and a ton of other helpful information about equipment, techniques, fixing mistakes, and more in The Miniature Painting Level Up Guide.

Get your copy here today.

Don’t miss out on all my other painting tips and recommended products that will take you from beginner to pro in no time. Click here for more!