How To Airbrush Varnish: 5 Easy Steps to a Fantastic Finish

Varnish is a (typically) transparent, durable substance that is used to give painted surfaces a protective coating.

Many varnishes dry clear, although some can be pigmented as well. Varnish can be applied to fine art, models, and many other painted materials.

As long as the appropriate steps are taken, varnish can easily be used in an airbrush in much the same manner as paint. 

List of Supplies 

In order to use varnish with an airbrush, you will need a few basic supplies.

An airbrush, an air source, varnish, thinner, protective gear, and cleaning items are all crucial elements in your varnishing arsenal.

Airbrush

Airbrushes can come with many different variations in nozzle, needle, fluid tip, and air cap sizes.

The best way to ensure the results you desire is to choose an airbrush that is specially designed for the specific project you have in mind.

My personal favorite is the Badger Patriot 105. It’s a dual-action, gravity-feed model that has served me extremely well through the years. You’ll find my complete review here.

Air Source

The type of air source you choose depends in large part on what kind of project you intend to use your airbrush on.

If you plan on covering a larger surface, you will want to use a compressor or a CO2 tank as your air source.

If you are using the airbrush to varnish a smaller surface or for one time use, you could use an airbrush propellant.

Three excellent compressors, fully reviewed, can be found in my article here.

Varnish

It’s a good idea to look for a varnish that is specifically made for use with an airbrush.

You can, however, always use an all-purpose varnish, as long as you thin it to a milk-like consistency before use and make sure to thoroughly clean your airbrush after the varnishing session.      

Thinner

Choosing a thinner that is made by the same manufacturer as the varnish is the best way to make sure that your varnish dries properly with a smooth and even finish.

Check the website for the brand of varnish you have to find out if they also make a thinner. 

Cleaning Items

It’s important to always clean your airbrush after use, especially when using varnish. Neglecting to clean your airbrush can lead to clogs that will keep your airbrush from optimal functioning.

Airbrush cleaning items can include airbrush cleaner and brushes, or you can make your own airbrush cleaner and use pipe cleaners and cotton swabs to scrub off excess varnish.

The easiest thing to do is to have a complete cleaning set, like this one with a glass cleaning pot and 10 brushes and needle tools, on hand.

Add a bottle of cleaning solution, and you’re good to go.

Protective Gear

Always work in a well-ventilated area or outdoors, and wear protective gear when airbrushing varnish.

Varnish can contain toxic chemicals that are not good for your lungs, so make sure to wear an airbrush respirator or a mask while airbrushing.

I use this mask – it’s comfortable and easy to put on and take off.

1. Select Varnish

It’s important to choose a high-quality varnish for use with your airbrush.

You may need to experiment with changing the viscosity of the varnish as well as adjusting the pressure settings on your airbrush in order to create a clean finish. 

Varnishes can also come in permanent or removable varieties.

Choosing a permanent varnish usually ensures that your project is protected from humidity, moisture, sunlight, and dust and is a good choice for projects that will see a lot of wear and tear or will be exposed to the elements.

Removable varnishes can be used on temporary projects that you foresee potentially painting over in the future. 

Varnishes can come in a range of finishes, from high gloss and gloss to satin and matte. 

Varnishes will also come in either a liquid or spray form. Spray forms come in an aerosol can and typically take a little practice in order to get an even spray.

Liquid varnishes are what can be used with airbrushes, although they can also be applied with a paint brush or sponge, and are designed to be applied in several layers. 

2. Thin Varnish

In order to get good results, you want your varnish to be the correct consistency for spraying through an airbrush.

If your varnish is thick or clumpy, you may need to thin it before use. 

You can use water to thin water-based varnish, but you will want to use a reducer or thinner to thin solvent-based varnishes. Vallejo makes an excellent product.

Varnish thinned with solvents is prone to bubbling, so you will want to mix and apply the thinned varnish with care. 

You can use a slightly larger needle when working with varnish, but you still may need to thin it out.

Add thinner to the varnish and mix it together until it is a milk-like consistency.

Mediums such as Flow Improver (find it here on Amazon) can also be combined with varnish to create the desired consistency.

3. Holding the Airbrush

The distance you hold the airbrush from the material you are varnishing depends on the size of the surface you are spraying.

If you are varnishing something tiny and detailed, like a model, it will be important to hold the airbrush at a closer distance, perhaps a few centimeters from the subject you are spraying.  

If you are varnishing a larger surface, you will need to stand back at least 6 inches from the material you are spraying.

In general, the bigger the area you are varnishing, the further back you will want to stand. 

If your varnish is splattering or dripping, that is a sign that you are holding the airbrush too close to the material you are spraying.

If, on the other hand, the varnish is coming out in a light spray that is barely covering your project, that is a sign that you are standing too far away from the subject. 

4. Apply Varnish Layers

When applying varnish, you want to work horizontally and spray it onto the surface with long, even strokes.

It’s always a good idea to practice your application technique before using it on the intended project. 

Each coat of varnish should be thin and even, and you will want to apply at least two coats of varnish to your painted material.

Make sure to allow each layer of varnish to dry for at least three hours before applying the next coat. 

Pay attention to any potential bubbling when applying the varnish, and make sure to smooth them out as you go – if you allow the bubbles to dry they will remain on your finished project. 

If you miss an area, you want to avoid immediately re-varnishing it. Wait a few hours until the first layer is completely dry, and then apply another layer.  

5. Clean the Airbrush After Use

You will want to thoroughly clean your airbrush out immediately after using it with varnish.

To effectively clean your airbrush, you will want to first flush the excess varnish from the cup, and then wash the cup with cleaner. 

To properly flush the varnish, you will empty any leftover varnish from the cup, then add cleaner (I recommend this one) or water to the airbrush.

Spray the cleaner through the airbrush until the spray is clean and contains no varnish. 

Your next step will be to unscrew the needle and wipe it down with the airbrush cleaner.

You can then remove the nozzle, nozzle cap, needle cap, and nozzle head cap, and soak them in an airbrush cleaning solution for around 10 minutes.

Use a brush or pipe cleaner to scrub any dried varnish from these parts. You can then use a small brush to clean out the paint passage.

Finally, use an airbrush cleaning wipe or a paper towel or rag dipped in airbrush cleaner or alcohol to wipe off the exterior of the airbrush.

Best Varnish for Airbrushing 

There are many different varnishes that can be used for airbrushing, and old pros will generally have a favorite that they recommend.

Some artists will use acrylic floor varnish, while others only use varnish that is strictly made for airbrushing. 

Choosing a varnish that is designed specifically for use in an airbrush is a good choice, especially for beginners.

Varnishes that are made for airbrushing may still need to be thinned, but the company that makes the varnish will typically make a thinner that is intended to work with the varnish.

Vallejo Premium Matte Varnish

The Vallejo Premium Matte Varnish is an excellent choice, as it is made specifically for use in an airbrush. 

Pros:

• This is a matte-finish varnish that is ready to paint on most surfaces.
• This varnish works great over watercolor or acrylic paint.
• It’s ready for use in an airbrush right out of the bottle.
• Can be diluted with Premium Reducer or thinned with Airbrush Thinner made by the same company.

Cons:

• Not a great choice if you’re looking for a shiny finish.
• Comes in a 2.02 ounce bottle, so not a cost-effective choice for varnishing large areas.

Liquitex Matte Varnish

The Liquitex Matte Varnish is made by a popular paint products company with high ratings.

Pros:

• Can come in sizes from 4 ounces to 400 milliliters, so it’s a good choice for varnishing larger areas.
• Permanent varnish that dries to a hard, flexible, non-sticky finish.
• Can be used with a range of Liquitex brand acrylic paints and mediums.
• Liquitex also offers removable versions of this varnish.
• Liquitex varnish finishes include High Gloss, Gloss, Satin, and Matte.

Cons:

• Has a higher viscosity, so it will need to be thinned for use with an airbrush. 
• Need to be careful with the application of this varnish to avoid bubbling.

Considerations When Airbrushing Varnish 

It’s important to understand the relationship between air pressure and varnish consistency when applying varnish via an airbrush.

When you are using a lower pressure, it’s essential to make sure that your varnish is properly thinned.

When using a higher pressure, it’s usually okay if your varnish is a little bit on the thicker side.

Before applying thinned varnish to your art project, it’s always a good idea to practice your application technique by spraying a test area first.

It’s better to use a piece of scrap paper, plastic, or metal to test your mixture than to apply it to a small section of the project you intend to spray. 

When thinning your varnish, start with a 1:1 ratio of varnish to thinner, and add more of either substance as needed from there. 

Troubleshooting 

Bubbles 

Bubbles may appear when you are mixing your varnish and paint thinner together, or they might pop up on the surface that you are varnishing.

Solution

Be sure to smooth out bubbles as they arise. Allow the thinned varnish mixture to settle before spraying any more.

To avoid bubbles in the first place, stir varnish and thinner together carefully, not vigorously, and use a gentle touch when spraying the varnish onto the intended surface.

Missed Area

If you missed an area in the varnishing process, don’t go back over it!

Solution

Allow the area to completely dry (for at least three hours). Once the initial layer is completely dry, apply another layer.

You may need to apply a third coat to make the finished product look even. 

Varnish Not Spraying 

If your varnish isn’t spraying or if it is coming out in spurts, there may be a range of culprits.

Solution

Use a higher pressure to spray the varnish. Make sure that the varnish is appropriately thinned.

If the airbrush seems clogged, remove excess varnish from the cup and then flush the airbrush out.

You will then want to clean the nozzle and needle using an airbrush cleaner and brush to make sure that they are not blocked.

Final Thoughts

Using an airbrush to apply varnish to your art is a great way to get smooth, even coats that not only protect your finished project but make it look clean and professional as well.

It should take at least seven hours to apply a minimum of two coats of varnish to your project, to allow proper drying time between application of layers, and to fully clean your airbrush after use.

The time from start to finish of the project will, of course, depend on the size of the area that you are varnishing.

Be sure to use the correct thinners with your varnish, and to take your time when applying the varnish in order to avoid bubbling or missed areas, and you will be an airbrush varnishing pro in no time!