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Just wanted to get some advice about thinning GW paints for airbrushing. I have loads of them and don't really want to get all new paints just for airbrushing. Some stuff I have seen on videos seems to suggest a VERY diluted ratio. Is this right? Like ten to one?!?! Seem very very thin. Is there enough paint in there then??

Here's my technique. Nice and simple. I thin about 1:1 (using liquitex airbrush medium), but paint can vary in thickness. You read a lot about the "milk" test, but I think that's an awful way to do it because it's never clear what people mean by "consistency of milk". Are they talking about viscosity? Are they talking about opacity? It never seems to match the milk I drink So what I do is:

- get some kind of cups to mix in (sleeve of medicine cups will last you forever).
- Add about 1:1 paint and thinner to start with and mix well.
- Tilt the cup to pour the paint into the airbrush. What you want to see is the paint run down the side of the cup as if it were a bit thicker than water. If it sloooooowly oozes down, thin some more. If it runs down like water, thicken back up with paint.

That's about it. There will probably be a little variation on the proper viscosity based on your particular airbrush and the pressure you use (I use 20 psi most of the time), but that's the general gist. The 1:1 ratio is just a starting point - for example Model Color is waaaay thick compared to Citadel paints. So just thin it so that you can pour it from the cup into the airbrush. You'll get a feel for the right amount to thin a given paint really quickly.

Cowbellicus wrote:
Here's my technique. Nice and simple. I thin about 1:1 (using liquitex airbrush medium), but paint can vary in thickness. You read a lot about the "milk" test, but I think that's an awful way to do it because it's never clear what people mean by "consistency of milk". Are they talking about viscosity? Are they talking about opacity? It never seems to match the milk I drink So what I do is:

- get some kind of cups to mix in (sleeve of medicine cups will last you forever).
- Add about 1:1 paint and thinner to start with and mix well.
- Tilt the cup to pour the paint into the airbrush. What you want to see is the paint run down the side of the cup as if it were a bit thicker than water. If it sloooooowly oozes down, thin some more. If it runs down like water, thicken back up with paint.

That's about it. There will probably be a little variation on the proper viscosity based on your particular airbrush and the pressure you use (I use 20 psi most of the time), but that's the general gist. The 1:1 ratio is just a starting point - for example Model Color is waaaay thick compared to Citadel paints. So just thin it so that you can pour it from the cup into the airbrush. You'll get a feel for the right amount to thin a given paint really quickly.

QFT. Solid advice.

That is incredibly helpful Cowbellicus. Very appreciated.

That's a pretty good guide cowbellicus. The only issue I have with it is you can't get the consistency your talking about with a 1:1 ratio. Most of the "really good" air brushers I've seen or talked to give the same explanation of how the paint should run down the cup but it's always a much higher ratio of water:paint. I find 7 or 10:1 water to paint works and just don't overdo the spray works best for me. It's all personal opinion and feel anyways.

Also you can add 2-3 drops of alcohol after you've thinned it almost all the way with water. That way it dries fast enough even using a thinner paint mixture allowing you to have smoother and better paint quality in general.

Chancetragedy wrote:
That's a pretty good guide cowbellicus. The only issue I have with it is you can't get the consistency your talking about with a 1:1 ratio. Most of the "really good" air brushers I've seen or talked to give the same explanation of how the paint should run down the cup but it's always a much higher ratio of water:paint. I find 7 or 10:1 water to paint works and just don't overdo the spray works best for me. It's all personal opinion and feel anyways.

Also you can add 2-3 drops of alcohol after you've thinned it almost all the way with water. That way it dries fast enough even using a thinner paint mixture allowing you to have smoother and better paint quality in general.

Cowbellicus wasnt talking about using water. Liquitex Airbrushing Medium was suggested, and I second the suggestion. No water should be needed really.

Even still I've found it to be a higher ratio. But like I said personal preference yadda yadda.

There are TONS of posts and videos on this, but here is the absolute best answer;

to the degree that works with the combination of your specific paint, airbrush, the pressure and your thinning medium.

In other words, try it, experiment and when is sprays well and gives good coverage, that is correct.

I cannot overstate the absolute critical importance of experience and experimentation in using, maintaining and working with an airbrush.

Depending on the paint, the size of the needle of your brush, the pressure you are running at and the viscosity of your thinning medium, how you are trying to paint (detail vs. base coating, vs. blending) will give your answer.

For example, if I am thinning my vallejo game color paints, and I need to cover a very small area with an even coat, I will use a small needle brush (.21) at about 17psi, and thin with arirbush medium.

But if I am putting testors acryl matte varnish on a finished tank, I will use a larger needle brush (.5), higher pressure (about 30psi) and a small quantity of 91% alcohol to spray the model.

If I am using liquitex gloss varnish I use a bit more alcohol and pressure, as its slightly thicker....etc.

The most important thing is to not thin with water...water just separates your paint within the fluid medium - it does not actually chemically "thin" it.....you need something that breaks the surface tension correctly - there are a lot of thinners people use (alcohol, windex, water with jet dry in it, airbrush medium, flow aid, taymia acrylic thinner, mr hobby 400 thinner, etc.).

I have used all of the ones I listed...personally, I find the best results from the airbrush medium (either golden brand or liquitex).

But again, you may like alcohol better, or windex (some say its not good for you to breathe the vapors...not a bad suggestion) but most importantly watch videos, test stuff, use different techniques....but find what works best for you.

Then, maybe start slowly transitioning to actual airbrush paints if you get tired of the thinning.....but there are tons of threads on that...but if you don't wnat to search...I suggest either vallejo model air, or minitaire.

best of luck, and always practice and experiment!

Look up what ammonia could do to the brass components in your air brush then stop thinning with windex forever. Not to mention it tints your paint blue because it contains dyes. Just saying. Also yes I understand all the brass in airbrushes is plated with nickel or chrome but why risk it at all?

Chancetragedy wrote:
Look up what ammonia could do to the brass components in your air brush then stop thinning with windex forever. Not to mention it tints your paint blue because it contains dyes. Just saying. Also yes I understand all the brass in airbrushes is plated with nickel or chrome but why risk it at all?

Which is one of the (many) reasons I don't use it anymore - my preferred thinner is actual airbrush medium....(except for varnishes....alcohol seems to give better results).

Personally, the dye was never an issue, but the corrosive and breathing issues related to ammonia (and the better performance of the medium) were reasons why I ditched it.

Some people swear by it, but some people smoke too....

With the model air, using my 0.2 nozzle.. i use normally do 3 drops of paint 1 drop of thinner. Have PSI on about 20? when im painting a face I thin more lower psi. YOu have to play around with it mate.

Here are two videos that I did on the subject:

I use les bursleys mix and thin appropriately.

I've found alcohol useless with gw paints. I use it with tamiya paints since they are alcohol soluble and gw are water soluble.

I have tried several airbrush thinners, and all have their merits.
From water, to Windex, all the way up to Golden, Liquitex et al...

My fav so far is the Createx Wicked Airbrush Reducer


I use it with Vallejo paints (air color, game color and model color), GW paints, Pebeo and Liquitex paints, with good results.

Wow. So much advice! Very exciting at the moment waiting for the mailman each day. Starting a new army, a new way of painting and loads of STUFF!!!

(I ordered Liquitex Professional Airbrush Effects Medium based on the most positive reactions, but I'm getting some Windexy type stuff for doing changes and cleaning with, I reckon)

Nice , glad we could help. Also if your in the position to do so experiment with different types of thinning and thinners. Because what is considered the best might not be the best for you. Biggest thing about airbrushing is to find what works best for you. Although there is nothing wrong with asking what other people use to get ideas!