If you airbrush Gunpla, you know the hobby tax is real. A small bottle of branded thinner like Tamiya X-20A or Mr. Hobby Thinner can cost $10 or more, and it goes fast when you’re painting big Master Grades or several kits at once. So I mixed my own from things you can find at a drug store and a hobby shop. Here are both recipes from my video: one with 99% alcohol, and the 70% alcohol version I actually ended up using.
Recipe 1: With 99% Alcohol
This makes a 60ml bottle:
- 2 parts distilled water
- 1 part 99% alcohol
- 1ml airbrush flow improver
- 1ml fluid retarder
For a 60ml bottle, that works out to about 40ml of distilled water and 20ml of 99% alcohol, plus the 1ml each of flow improver and retarder.
Recipe 2: The 70% Alcohol Hack
Most online recipes call for 99% alcohol, but I couldn’t find any when I made my batch. So I used regular 70% alcohol from the drug store instead. This version makes a 120ml bottle:
- 1 part distilled water
- 1 part 70% alcohol
- 2ml airbrush flow improver
- 2ml fluid retarder
For a 120ml bottle, that’s about 60ml of distilled water and 60ml of 70% alcohol, plus 2ml each of flow improver and retarder.
What Each Ingredient Does
- Distilled water is the base. Use distilled, not tap water, so you don’t add minerals to your paint.
- Alcohol (99% or 70%) thins the paint and helps it dry faster.
- Flow improver helps the paint flow smoothly through the airbrush.
- Fluid retarder slows drying a little, so paint is less likely to dry on the needle tip and clog your airbrush.
How to Mix It
- Start with a clean dropper bottle (60ml for Recipe 1, 120ml for Recipe 2).
- Add the distilled water and the alcohol.
- Add the flow improver and fluid retarder.
- Cap it and shake well. Label the bottle so you know what’s in it.
Before You Spray
- Test it with a small amount of paint on a spoon or scrap part before using it on a kit. Not every paint brand reacts the same way to alcohol.
- Alcohol is flammable. Mix and spray in a ventilated space, away from open flames.
- Wear a respirator when airbrushing.
New to painting? Start with the Gunpla Paint Types guide to learn which thinner goes with which paint, then try the Water vs Alcohol Paint Test.