How to Thin Acrylic Paint for an Airbrush When Painting Miniatures

  • By: Richard
  • Date: August 24, 2021
  • Time to read: 13 min.

Why You Should Thin Your Paint for an Airbrush

Painting miniatures is a delicate process that requires skills and precision, one of the most important aspects of this art form, which many beginners are unaware of or neglect to pay attention to prior. A crucial step in painting any miniature is thinning your paints. Putting on too much paint can lead to disastrous results, including bald spots where you didn’t want them and ruining what was underneath the thick layer if it happens early enough in its application stage. Furthermore, the thicker coating makes cleaning up more difficult later on down the line when things go awry with your project!

Some artists like using a brush, and others prefer airbrushes because they offer different results – softer lines in some cases for those who want that effect, more detail available when fewer coats are needed on the canvas as well as being able to work faster than someone painting by hand which often allows them time spend doing other art-related projects. Airbrush users also benefit from easier cleanup while still achieving similar effects of brushwork combined with spray guns such as:

  • A thick base coat that hides the details of the miniature.
  • A look that is glossier than you want.
  • Cracks in the paint.
  • Either a damaged brush or a clogged airbrush.

Thinners to Use With Your Acrylic Paints

There are a few different types of thinners available for those interested in using acrylic paints. The substances you can use range in price from free to around $15. Which one you choose is up to your personal preference and budget, with the most expensive option being that which gives you more control over consistency while not costing any money at all!

Substances you can use are:

Tap Water

Tap water is the most commonly used thinner, not because it’s the best but free. If your tap water has a lot of minerals in it or if you live near an industrial area with heavy pollution, your paint can end up looking gray and feeling rough to work on due to these impurities.

Distilled or Deionized Water

If you’re worried about your paint but want to use water as a medium, distilled or deionized water is the best choice. It removes all impurities and doesn’t mess with the paints in any way.

Airbrush Thinner

There are thinners specifically made to paint for airbrushing. These make sure that your paints have the best consistency possible, so they will last longer and give you better coverage with less mess!

Mediums

There are many different types of paints, but some will not thin out with water. If you need to mix these for a lighter color or thinner consistency, use paint mediums specifically made.

Types of Paint for Airbrushing

If you’ve been struggling to make your paint the perfect consistency, we have good news for you. Many different paints can be used with an airbrush, depending on what look and feel you want. Some never need thinning at all!

Some paints are specifically made for airbrushes, so they don’t need thinning at all. Some other paintings require specific mediums to make them work well in an airbrush and flow easily.

Below is a list of the most common types of paint that people use when painting with their airbrushes.

Airbrush Paints 

Airbrush paints come in a variety of colors and are designed to work smoothly with an airbrush. But don’t think you have to be limited by the paint that comes from a tube! Vallejo, Citadel, Lifecolor…these companies make their special brands specifically for use on your favorite painting implement. There is no need for thinning either- they’re perfect just as is or can be changed up if desired.

Base Paints 

The best way to thin base paints is through trial and error. Different companies and even different colors will have varying thicknesses, so start with a thinner paint-to-paint ratio of 1:1, then adjust from there if needed. It’s always better to err on the side of being too thin than not enough because you can’t correct for when it turns out too thick in layers!

Glazes and Shades 

Glazes and shades are a type of paint that doesn’t need to be thinned before use. If you feel the need, only work with mediums created specifically for those particular paints.

How to Thin the Paint

There are many simple ways to thin out paint, all with different benefits and uses. If you like the consistency of milk, then adding water is a quick way to produce some fascinating effects on your painting. You can also add alcohol or turpentine if desired, but don’t mix them as they don’t compliment each other well!

Here are the two most common ways of thinking.

In a Cup or Bottle

If you feel bold and experimental, mix up a large amount of paint in the bottle to be ready to go. If not, or if you want to experiment with different ratios without wasting too much time thinning your paints every single time for an uncertain result, then use small cups instead!

To mix into a cup, you should:

  1. Put a few drops of paint into the cup.
  2. Add 2-3 drops of water or thinner to the paint.
  3. Use an old, cheap brush to mix the two. You don’t want to mess up an expensive brush mixing.
  4. Continue to add water or thinner a drop at a time until you get the consistency of skim milk.

In Airbrush Cup

With a cup, you need to mix your paint and then transfer it into the airbrush. Using an Airbrushing Cup eliminates this step by allowing you to just put the paints directly in there! You can even get disposable cups for easy cleanup.

To mix into your airbrush cup, you should:

  1. Add 2-3 drops of water or thinner to the airbrush cup. If you start with paint, the paint might get into the airbrush tube, clogging the brush or making it harder to clean.
  2.  Add 2-3 drops of paint to the airbrush cup.
  3. Use an old, cheap brush to mix the two.
  4. Cover the nozzle with your finger, and move the lever back. This will cause a backflow that will further help mix the paint and thinner.

10 Methods for Thinning Paints for Miniatures and Models

I’ve been painting miniatures for a long time, and the one thing I always have trouble with is finding an appropriate paint consistency. The paints that come in pots are too thick, but if you thin them down, they run all over your table or hands before making it to the model! There must be 10 different ways to make this problem go away:

  1. Water
  2. Inks and Shades
  3. Glazing Mediums
  4. Flow Aids or Improvers
  5. Varnish (Water Soluble)
  6. Airbrush Thinner
  7. Hobby Mixing Mediums
  8. Windex or Other Glass Cleaners
  9. Rubbing Alcohol (Isopropyl, Isopropanol, or 2-propanol)
  10. Slow Drying Mediums

For the most reliable results in miniature painting, you’ll want to know how your choice of paint thinning medium affects different techniques. For example, some are better for specific color blending, while others might be more appropriate if airbrushed or glazed onto miniatures. The general rule is that thinner paints behave very differently on a palette and brush than thicker ones, so knowing this will greatly improve your technique!

For those who enjoy hobby-level model making (such as myself), it can sometimes be difficult to figure out which type of paint consistency works best with certain modeling techniques, such as when using an airbrush versus traditional hand application methods like brushing or dabbing at the surface with a sponge applicator.

How To Thin Createx Airbrush Paint

Createx’s Airbrush Paint can be thinned to increase its use in miniature painting. Their performance can also be improved with the help of 4012 high-performance reducer and 4030 Balancing Clear as a clear base medium that will make them more durable, easier to spray and adhere better.

GOLDEN Airbrush Colors

GOLDEN High Flow colors are formulated from a safe and archival 100% water-based acrylic emulsion, incorporating only the most lightfast pigments available. They are ready to use, no dilution required as they are finely ground, they easily spray through the smallest orifices for airbrushes. GOLDEN Airbrush Medium can allow for more transparent color without compromising film integrity and permanency. Lowering pigment load by adding this extender will do just that!

You’re in luck because you’ve stumbled across the secret formula for mixing paint. The first thing that confuses people when they mix paints is deciding on a water ratio or sometimes just watching their colors separate into different layers instead of merging. The easiest way to avoid mixing paints that are too thick is to use this handy chart.

Paint  Thinner Ratio Pressure Clean-Up
Polly Scale Distilled Water 3:1 or 4:1 15-25 H2O/Washer Fluid
Floquil Solvent/Thinner 2:1 or 3:1 12-20 Lacquer Thinner
Badger Modelflex Water Very little, if any 25-30 H2O/Washer Fluid
Tamiya Alcohol 2:1 15-20 H2O/Washer Fluid
Vallejo Model Color Vallejo Thinner 3:1 20-25 Lacquer Thinner
Vallejo Model Air Vallejo Thinner Very little, if any 20-25 Lacquer Thinner
MicroLux Vallejo Thinner Very little, if any 20-25 Lacquer Thinner
Humbrol Water 1:1 or 2:1 15-20 Water
GunzeSangyo Alcohol or
Distilled Water
1:1 or 2:1 20 Water/Alcohol
Scalecoat II Solvent/Thinner 1:1 15-20 Lacquer Thinner
ModelMaster(Testors) Universal Thinner Very little, if any 18-20 H2O/Washer Fluid
Future
Alclad II Lacquer Thinner    Very little, if any 12-15 Lacquer Thinner
Pactra Lacquer Thinner 1:1 20-25 Lacquer Thinner
Pactra Acrylic None 25-30 H2O/Washer Fluid
Lifecolor Acrylic Distilled Water, Washer Fluid 1:1 12-15 H2O/Washer Fluid
Craft Store Acrylics 25% Liquitex Slow-Dri, 25% Flow Improver, 50% water 1:2 20-30

FAQs

What is the best solvent for acrylic paint?

A simple answer to a complex question! Solvents are, in fact, not the best solvent for acrylic paints. Acrylics tend to dry faster with the use of solvents. A better alternative is water which helps prevent lap marks from drying and produces hard, smooth, and shiny surfaces on your miniature projects.

But when it comes to airbrushing – using an airbrush provides control over paint flow rates but applying thinned paint through an airbrush requires different methods than just thinning with water alone. The thinner you apply the paint, the less the surface tension resulting in a bigger spray pattern, thus affecting your ability to produce fine details in small areas or near edges.

How do thinners affect paint performance?

Paint performance directly affects the surface appearance, spray pattern, and adhesion of your miniature projects. Paints are formulated using solvents to prevent lap marks (uneven drying) and control the application level per area. Thinners tend to add more solvent resulting in less control over paint flow through the airbrush when thinning paints. The result is a big spray pattern causing overspray on areas that should not be painted or apply too much paint, which results in uneven drying and blurring edges. This greatly affects your accuracy, especially when applying wonderful details like bolt heads on armored vehicles and eyes and achieving smooth transitions between different color shades on your mini-projects.

Experimenting with different ratios will assist you in applying thinned paints while producing high-quality results. Also, remember that each brand of paint follows different performance characteristics – their separation and drying time to name a few.

How can you apply acrylic paint to wood?

Acrylic paints do not evaporate or leave behind any residue while applying on wood. This makes it easier to apply thinned acrylics as they dry very fast and harden without leaving behind a shiny film when using water in your mixing palette.

Since paint solvents are not required, thinning techniques can convert projects with plastic models that receive the paint through an airbrush. You will need to change your spray nozzle (0.2mm) if you plan to slowly build up layers of color per model since this nozzle size is good for larger surfaces like big tanks or planes.

Authentic results can indeed be achieved by applying coats of diluted paint after priming your miniature project first unless we’re talking about a specific paint like hobby color acrylics which serve as primers in itself.

Remember that the aim is to have full control over your project by applying thin and diluted coats of color to achieve smooth surface transitions and produce fine details with an airbrush. Building up layers using water to dilute the paint will greatly assist you in achieving quality results on both large surfaces such as vehicles and smaller projects such as buildings or terrain boards.

What is Layering technique when painting with acrylic paint?

Another method to apply thinned paints on your miniature projects is by using a layering technique. This involves applying a coat of diluted paint followed by water and another coat of diluted paint until you achieve the desired color shade or effect per surface.

This also requires more drying time since each layer needs to dry before applying another, so plan accordingly when working on your project. Ideally, work on one part at a time, put it aside and come back later after waiting for some time.

There are many techniques to choose from when painting with acrylics and depending on the colors you want to use, different methods will be more suitable.

This is an instrumental technique, especially on vehicles and big projects where you want to highlight the edges and crevices of your models, as seen in the picture above.

Miniatures can be painted with acrylics, but other paints are more suited for this task, like enamel or watercolors. Be sure to use thinners when airbrushing these since they have different characteristics compared to acrylics.

Acrylics will dry much faster than washes due to their solvents, meaning we’re able to spray in between coats which greatly assists us in building up layers using this method.

Will paint thinner destroy plastic?

Acrylic paint thinner is not harmful to plastic but make sure your miniatures are safe where the liquid will not reach them.

The same as when you’re using enamels, spray from different angles for best results. Just be mindful that this takes time since each coat needs to dry before applying another one and it’s recommended that you leave ample time before handling the project again, just in case.

An airbrush is a great tool for spraying thinned paints on your projects as it provides consistent results while saving both time and effort – most importantly, precision while building up layers.

Remember that acrylics react more quickly to solvents than enamels so they will smudge or destroy previous layers of color if we’re not careful. The main reason we choose to thin the paints is that each layer requires time to cure and if it’s thick, you will need a long drying period before spraying again.

What type of paint works best with DnD miniatures?

Citadel Colour paints are great because they adhere well to plastics. For example, the Citadel paint line works better with plastic miniatures than hobby color acrylics. A simple way to achieve this quality is by using GW’s thinner before applying the paint on your projects since Citadel lives up to its name of being a good choice for painting Citadel Miniatures.

If you want something that will dry faster while also achieving smooth surface transitions, I think Vallejo Game Colour offers an amazing finish which makes them ideal for airbrushing.

For fine details, it is necessary to have thinned paints for any possible effects since thick coats will only obscure these parts and make them look like blobs.

How do you remove paint from plastic models without damaging them?

Painting miniatures is fun, but cleaning them can be quite frustrating, especially if you’re dealing with many parts. The easiest way to remove any unwanted paint (or color) on the plastics is by using an eraser or toothpick since they are a similar consistency compare to modeling putty.

When removing paint from plastics, always remember that too much rubbing will result in scratches and marks, so use the erasers lightly and only apply light pressure when needed. If there’s excess paint around the details, try using some of your thinners for this rather than water, as it may help lift it off more effectively.

An alternative way to do this would be by soaking the part overnight in odorless thinner, waiting for the paint to loosen up and then gently scrubbing the affected areas with an old toothbrush.

Once we’re done, clean them thoroughly with water and let them dry before using your model again.

To avoid this in the future, make sure that any time you work on a project is always spent painting and not cleaning. This way, it will be easier to wash away what’s leftover from the paints after working on them.

How do I thin oil-based paint?

Oil-based paints help create a hard and non-glossy surface if applied correctly, but as they normally come, they are quite thick, making them unsuitable for airbrushing.

To apply these properly, we must thin them first to make the paint more fluid inconsistency, enabling us to spray it in layers. Without proper thinning of acrylics, your project could push out bubbles or cause clogging on the nozzle.

The best way we can do this is by shaking up milk (crème Fraiche) with the paints then stir the mixture with a spoon (it should be directly mixed with the color). You should remember that not all colors make good base coats, while some are better used for highlights and shadows.

The best way to test them is by spraying on a piece of cardboard, as this will allow us to figure out if we’ve mixed them correctly before trying anything on our project.

If you’re unsure how much paint to thin your colors with, remember that less is more when doing this since too much fluidity will create an uneven surface while making the model sticky. But if the consistency is too thick, it will take forever to dry before you can continue working on another layer, so be careful in applying the paints.

Can alcohol ruin acrylic paint?

For most acrylic paints, I don’t recommend using rubbing alcohol as thinner since they contain serious solvents and other chemicals that damage the paint’s consistency.

Some brands of these paints, such as Vallejo Game Colors, are designed to be used with different types of solvents, so you can get away with using this kind while making sure not to use anything too strong, which may cause unwanted results.

If you really want to try it out on airbrushing, then a good alternative would be isopropyl alcohol or even naphtha, commonly used in lacquer-based varnishes.

Conclusion

Just remember, there is no set formula for thinning paint. The amount of thinner you use will change depending on brand and color. But the only thing that’s going to perfect your process is experience with experimentation – don’t be afraid! If you experiment more often, then in time, your ability to create the right consistency for paints will become second nature as well as an art form all its own.

Richard

Hi! I'm Richard Baker, a miniature painter who has been painting for about ten years. My website is packed with great advice that I've learned from both books and personal experience on building and painting miniatures.

Scale Modelling Workspace

Previous Post

Scale Modelling Workspace – Create Your Space

Next Post

Beginner’s How-To Guide To Plastic Modeling

Beginner's How-To Guide To Plastic Modeling