Make Homemade Airbrush Thinner

An homemade airbrush thinner gives absolute control over your paint consistency.  It’s cost effective, and easy to do with this recipe. 

There are many options when it comes to what you use to thin down your airbrush paint.  In fact, it’s one of the most frustrating part about learning how to airbrush.

Whether you are budget savvy or simply not satisfied with the products available on the market, an homemade airbrush thinner is a good way to go.

This version is different than a DIY commercial thinner, which aim to mimic the stuff you buy.  It is how miniature painter extraordinaire Brandon Palmer of GMM Studios thought me many moons ago.

Make Homemade Airbrush Thinner

There are only 2 things you need for this, and one is practically free.

  • Water
  • Isopropyl Alcohol

Simple and straightforward.

Isopropyl alcohol comes in many concentration, usually ranging from 40% to 99%.  For our purposes, the higher the better.

In fact, I would not buy anything below 70% for our homemade airbrush thinner.  Any lower and it defeats the cost saving purpose, not making it worth the trouble.

Whatever you end up buying, I would stick to that until forever.  If you can only find 70% where you are, don’t go out of your way to get 90% if you see it or when it’s time to make a fresh batch.

This is because over time, you can fine tune the ratios of your own mix to suit your preferences.  Changing the concentration of alcohol in your homemade airbrush thinner means you have to start this fine tuning from 0.

In this example, we are using 90% Isopropyl Alcohol, because it’s the one I’m using, and the most common one here.

The best starting ratio is one part alcohol for nine part water. 

This will vary slightly based on your preferences.  Depending on the outcome, here’s how to fine tune your mix.

If you need to pour too much thinner and your paint becomes almost transparent, it means you don’t have enough alcohol in your solution.

If you have very little thinner and your paint turns to a watery consistency and does not adhere to your primer, you have too much alcohol.

Pro Tips

Start your mix in a very small quantity.  One small part alcohol and 9 small parts water.  If this mix is wrong, discard it (or keep it to clean your airbrush at a later time).

Don’t add more water/alcohol to this mix, make a new batch with slightly better ratios.

You want to perfect your mix before you make it in large quantities, and half a mix with some thinner added, then water added then alcohol added means you won’t ever get back to this exact ratio in a lifetime.

The goal is to take out the guess work.  You want to make your life easier, making new airbrush thinner should not be cause for anxiety.

It’s better to start with too little alcohol rather than too much.  Too much alcohol in your mix will cause paint to break down and can damage both your airbrush and your primer.

Storing & Using your Homemade Airbrush Thinner

You also want some sort of container that makes your concoction easy to use.   I like making a big batch that’s easy to pour, and have a handier and smaller version that I use and refill from my big batch.

Container wise, you can use anything that’s air tight, because alcohol his overall quick to evaporate, something you don’t want in a big batch that can sit in the container for a while.

Your handy version, the one you use to pour in your airbrush, is a matter of personal preference.  I like the ones with a long nose, they feel more precise overall.

Once you find one you like, get two of them so you can use the second one for your airbrush cleaner.

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