The versatility of acrylic paints makes it a go-to paint for artists of all skill levels. You can play around with its consistency to mimic other mediums like stains and varnishes.
You can achieve this and more effects with relative ease, but only with the correct acrylic paint thinner. Also, the process must be done right.
What is acrylic paint thinner? Acrylic paint thinner is a medium added to acrylic paints with the purpose of altering its consistency to be less thick, lighter, thinner, or runny. Mediums that can be used to thin acrylic paints include water, acrylic mediums, and acrylic binder.
There are a couple of commercial acrylic paint thinners for the job. However, water is a natural acrylic paint thinner, and its ubiquity makes it more commonly used.
If the thought of exploring the fantastic multi-effects of thinned acrylic paints excites you, then read on. In this post, we take you through the process of how to thin acrylic paints properly and what to use.
What Can You Use As Acrylic Paint Thinner?
Acrylic paint is known for its many admirable qualities; speedy drying, workability, low toxicity due to the absence of lethal VOCs, and a low key smell. The contributing factor for most of these characteristics is that it is a water-soluble paint.
Acrylic paint is composed of two components: a pigment and a binder. This binder is usually an acrylic polymer emulsion which is acrylic polymers suspended in water.
Therefore, acrylic paint is water-soluble. It will break down and mix readily with anything that is already part of its composition, and that is why it is easy to thin out.
Do you need to thin acrylic paint? Not at all; it’s a personal preference. The consistency of paint varies from one brand to another. It can be light, medium, or heavy.
However, the majority of professional acrylic paints are heavy-bodied, which can be hard to spread. In such cases, thinning is necessary to transform them to a smoother consistency for easy application.
Another reason you may want to thin your acrylic paint is to make it possible to apply specific techniques like airbrushing, dot painting, pouring paint, etc.
When the term thinner is mentioned in art, it often refers to turpentine or mineral spirits. That’s probably because oil paints are the traditional medium, and mineral spirits are used to thin them.
On the contrary, that is not the thinner that should be used with acrylic paints, unless you are cleaning dried acrylic paint off brushes and palettes. There are better alternatives.
So, what do you use to thin acrylic paint?
Water is the most preferred paint thinner for acrylic paints due to its accessibility. It breaks down and mixes readily with acrylic paints.
As mentioned, water forms part of the acrylic paint binder, which is an acrylic polymer emulsion. For this reason, it mixes well in acrylic paints, unlike oil paints, whose composition is not water-based.
However, this does not mean pouring water into acrylic paints without a strategy. You must do it cautiously so as not to over saturate the paint.
Loading too much water in your acrylic paints ends up disrupting the balance in the binder and hindering proper adhesion. Consequently, the coat of paint will peel or chip much faster than you would have anticipated.
When thinning acrylic paint with water, you must take caution. Moderation is key. The recommended ratio is one part water to two parts acrylic paint.
The water content should never exceed 50% of the acrylic paint. You might even want to start with 30% water and see the outcome first.
Adding water to acrylic paint as thinner can yield any of these effects; watercolor, gouache, a wash, or a stain, depending on how much water was added. The water sinks into the substrate, taking some pigment with it to the bottom, resulting in a matte, less vibrant finish.
2. Acrylic Mediums
With some cash to spare, you may opt to invest in commercial acrylic paint thinners. These are usually acrylic mediums, like pouring mediums designed to improve the flow of acrylic paints.
They are marketed in many names, including flow aid, flow improvers, pouring mediums, etc. Acrylic paint thinners blend quickly with acrylic paint into a lighter consistency. The best thing about acrylic mediums as paint thinners is that you do not have to worry about precise measurements.
There’s no risk of undermount paint from going overboard with water which causes peeling. You can be as liberal as you need to achieve desired effects.
Want some recommendations? Liquitex Professional Effects Medium is one of the best acrylic mediums for thinning acrylic paint. It works well with a variety of acrylic paint brands.
Another fantastic option is the Winsor & Newton Professional Acrylic Medium.
3. Acrylic Binder
Acrylic binders are basically acrylic polymer emulsions and do the same thing; lower the viscosity of acrylic paint. Acrylic polymer emulsion is the binder in acrylic paints. So it is acrylic paint minus the pigment, and you will be adding its component to thin it.
Unlike water that sends pigments under, these acrylic binders allow the pigments to be suspended on the top. Since they are binders, they form the hardened coat when the acrylic paint dries.
The effect is different in appearance to that made by water-thinned acrylic paint. Acrylic binders create a more transparent but slightly vibrant coat that looks like a glaze.
Because you are less likely to mess up with acrylic binders as paint thinner than water, they are the best acrylic paint thinning choices for beginners.
How To Thin Acrylic Paint
Thinning acrylic paints is as straightforward as you would like to think. However, you must give some thought and careful planning to the process to ensure excellent results. Here are our best tips on how to thin acrylic paint:
1. Prime Your Surface
Priming can never be overemphasized while painting, more so when you thin your acrylic paint. Primer provides a solid base for your painting. It helps make the colors stand out, especially since thinning may faze out the intensity a little bit or a lot depending on the ratio.
Another primary role of the primer is to enhance the acrylic paint’s staying power. The adhesion of acrylic paint can be compromised by thinning the paint with too much water.
Gesso is the best primer to use. It is compatible with several substrates, and many seasoned artists vouch for it. It is beneficial for sealing absorbent substrates.
As you know, thinned acrylic paint, being much lighter, seeps into surfaces more readily. The end results could be underwhelming without gesso.
2. Use The Right Brush
Artists will often have their brush preferences depending on skill level and technique. The standard #6 brush is the most prominent one, and this is probably what you already have and intend to use.
However, for better results, we suggest getting something broader for the initial wash. You can pick a 4-5-inch wide brush instead.
Foam brushes tend to perform better at laying down acrylic paint more evenly than bristle brushes. This improves the overall appearance of your painting.
3. Mix Cautiously
When thinning with water, distilled or filtered water would be a much better choice than water from your faucet – less impurities like chlorine which can affect paint.
Thinning acrylic paint with too much water can be catastrophic. Your painting may peel, crack, or chip within no time, which would be a waste of time, paint, and canvas.
Therefore, you have to be very precise with measurements when using water as thinner. You should measure the water and acrylic paint by volume.
Unless you are a professional at this, try to keep the water at 50% or less the volume of acrylic paint. We suggest doing even lower volumes like 30% for non-absorbent surfaces.
With acrylic mediums and binders, you can get away with a heavy hand or non-precise measurements. If anything, only the color intensity of the paint will suffer.
Still, for best results, thin the paint with 50% of acrylic medium or less. Pouring medium, potent thinners in particular, should be about 20% or lower.
When it comes to the thinning procedure, you should have a separate blending cup or any other container that suits the purpose. You want to dab a little paint and mix it with the thinner there before painting with it.
The reason for doing this is because acrylic paint dries rapidly. To avoid wastage, it is best to thin it in small batches in a separate container.
You can thin some more as you go, as opposed to thinning the entire bottle or tube of acrylic paint only to have a lot leftover. Do the mixing using a clean, spare paintbrush. A palette knife is customarily the tool used for paint mixing.
However, when thinning acrylic paint, a paintbrush will be the most ideal in this situation, as you’ll get the exact feel of the paint’s consistency. A paintbrush is also thorough and ensures all lumps are squished.
Once done, let the thinned paint sit undisturbed for a while. About 15-20 minutes just so it mixes entirely before use.
4. Layer Skillfully
One of the key painting approaches every artist learns when starting out is the fat over lean approach. This is the safest approach when using thinned acrylic paint.
What does it entail? With this process, you paint in layers but increase the thickness in every subsequent layer. In the end, every layer is thicker than the one beneath it.
How is this helpful? Well, as the paint dries, it undergoes some shifting from expansion or shrinkage. This is due to unstable environmental conditions.
The fat over lean approach reduces the chance of your paint cracking. As you know, thinner layers crack more easily than thicker ones.
But with this method, they’ll be under. Therefore, you should be wary of finishing your piece with light washes. Let the thickest and last coat be at the top.
Acrylic Paint Thinner For Airbrushing
If you opt to go the airbrush way instead of using traditional brush strokes, you’ll still need to thin the airbrush paint.
Airbrush paint must always be thinned before use, even if it’s labeled as “ready-to-use,” for the best results possible. Thinning brings it to the right consistency to be sprayed through the nozzle for a consistent spray job.
Failure to thin airbrush paint results in uneven or splattered dispelling patterns and could result in the nozzle getting clogged. You also need to apply more pressure, resulting in hand fatigue and the ultimate frustration of uneven results.
So what acrylic paint thinner do you use for airbrushing? Water, rubbing alcohol, or airbrush paint reducers are the three acrylic paint thinners that are best for airbrushing.
You can use either water or isopropyl alcohol, whichever is at hand, and mix it in a 1:1 ratio with the airbrush paint. Pour the mixture into a container and whisk it or give it a vigorous shake if it is capped. It should be thin enough for use.
Another alternative is an airbrush reducer. These are commercial acrylic paint thinner s for airbrush.
Most brands manufacture their own airbrush reducers to be used alongside the paint brand. But if you are having trouble finding one, settle for Vallejo Airbrush Thinner.
It is super effective and works with a variety of acrylic paint brands. It is also formulated to preserve the paint’s color, durability, and adhesion properties.
Please note that thinning with water, rubbing alcohol, or even some airbrush thinners can lead to under bound paint. And this is where an airbrush acrylic medium comes in.
Airbrush acrylic mediums are acrylic paint thinners on their own but with an added advantage. They don’t interfere with the paint’s ability to remain stable after drying, minimizing flaking.
Therefore you can choose to use it as a thinner on its own or, to be on the safe side, add it to the airbrush paint after thinning with water or rubbing alcohol to reinforce its holding power.
You may consider Liquitex Professional Effects Medium. It is one of the most highly-rated airbrush acrylic mediums. Remember there are other factors you should consider when thinning your airbrush paint, such as airbrush quality and nozzle size.
These come in different diameters, which determine how thick or thin the paint stream is. The smaller the nozzle, the thinner you can get the consistency.
Another critical tip when airbrushing is to consistently clean the nozzle to prevent clogging. This is a familiar occurrence with airbrushes, and simply wiping the nozzle with the acrylic medium or thinner gets rid of any potential blockages building up.
Can you make your own acrylic paint thinner? Yes, you can. But only if you are on top of your game. There are plenty of recipes for acrylic paint thinners and airbrush paint thinners as well. Nonetheless, we recommend leaving this kind of trial and error to the professionals if you are not one.
Can you use rubbing alcohol to thin acrylic paint? Yes and no. You can use rubbing alcohol to thin acrylic paint for airbrushing since it evaporates with the spray. You may also use it to loosen up dried acrylic paint on brushes and palletes or other surfaces.
However, it may only be added to fresh acrylic paint as a thinner if the paint is not water-based (is solvent-based). Otherwise there are better options like water and acrylic mediums.
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