Ratio of Tamiya paint to thinner

With their lacquer thinner, I start at 1.5:1 thinner to paint and thin to taste. I've kind of developed an eye based on the consistency of the paint on my stirring paddle. But usually 1.5 or 2:1 for standard coverage. At 9:1 you can start doing filters, fading and shading. 

Not sure about X20A, but I assume it's probably similar. 

First off to the forum!  It will really depend on what you're trying to accomplish.  For instance, for a general basecoat I thin Tamiya paints (with laquer thinner) at about 30% thinner and 70% paint ratio typically shot through the airbrush at around 20psi.  For different effects, i.e. a basecoat of paint after preshading panel lines, I will thin 50:50 in order to give the paint a more translucent effect allowing me to build the layers of paint up a little at a time (shot at around 15-18psi).  Tamiya paints are excellent when it comes to high thinner:paint ratios and being able to spray at a low psi.

Temperature and humidity will play a role in things.  I would definitely recommend having a spare model for "target practice" and try different ratios of paint and thinner shooting them at different psi. 

The reason there is differing opinion is because there are a few factors that need to be considered when thinning - different airbrushes with different needle/nozzle combinations, environmental factors (heat, humidity) & user "style" all have an effect on what the best thinning ratio for each airbrusher is.

Your best bet would be to start at 50/50 & see how you get on;

Paint too dry or trouble getting good atomization - increase the % of thinners,

Finish too wet or thin - decrease the % of thinners.

This is from Tamiya's website, but can be taken with a pinch of salt as most people will use more thinners;

Proper ratio for paint thickness differs according to
weather conditions. Rough guidelines of thinning ratio is
2:1-3:1 ( Tamiya Acrylic paint : thinner).

I use a Badger 150 bottom feed airbrush. I have found that a 2 parts Tamiya paint to 1 part Tamiya X20A Thinner worked best at about 16-20 psi.

If I am doing detail work, I go with a 1 to 1 ratio and about 12 psi.

I'm getting the Steenbeck AB-AS-186 Airbrushing Kit With Evolution 2 in 1 Airbrush. Would you recommend it?

Is it a good kit?

Guy.

The H&S Evolution is a brilliant airbrush. You'll love it.

I'm using the Paasche H, single action rig that my wife bought me for Christmas a couple years ago.

I'm probably not thinning my paint nearly enough.  Here's how I do it.  I fill the paint cup about 2/3 of the way up.  I then use an eye dropper to put in enough rubbing alcohol (when I use Tamiya acrylics) to put a layer over the top of the paint.  I then stir it with a toothpick to blend it all together.  I use about 20 PSI and it comes out just fine. 

Here's what works for me:

For acrylics, I have a little 1oz bottle, with an eye dropper top. I put regular rubbing alcohol in it (70% isoprophyl). It's far cheaper than brand name acrylic thinners. I put about 3-4 drops of liquitex "flow-aid" in it, which you can get at Michael's or an art supply store. For tamiya acrylics, I put the paint in the airbrush paint cup and then simply eyeball how much thinner I need (usually around 30%). It should look about the consistency of milk. I stir it up with a toothpick and then paint at around 18psi.

airbrushing and thinning is a personel thing ,,, how far from the model are you spraying ,,, what color ,, how thin ,, what pressure ,,what needle,, how far back are you pulling the trigger ..there are so many variables

 you can use the guidelines but in the end you will have to learn what works,,, it's been said a million times but practice,,, will reveal the best answer

 also when starting out ,,, using the manufactures thinner is a big help...trying out alternate methods and products in the midst of learning to airbrush is  not the best advice.you will find what works best for you as you progress.

Thank you for everyones advice I'm going to buy a little Tamiya Morris Mini 1/24 scale as a practice dummy. 

I'm also buying some books which are affiliated with this site on www.amazon.co.uk to try and guide me on my way.

I will obviously have to practice and see what works best for me. My main targets are to airbrush my 2 new F1 cars both 1/12 scale and Tamiya:

McLaren Honda MP4/6

and

Williams Renault FW14B.

Guy.

some will require more thinning then others because the consistency from bottle to bottle won't always be the same. you want to thin to the consistency of milk.  

Do you mean by milk that it is slightly thicker than water and if tilted will loosely stick to its container?

Guy.

just tap the stirring stick inside the cup. watch it drip along the side. if it flows very slow then it's still to thick. you want it thin but not waster thin. most will use water thin for detailed work. 

Some things cannot be known- this is one of those.

Just to let you know I'm getting the Harder and Sttenbeck Evolution Silverline 2 in 1 airbrush instead of just the Evolution 2 in 1. 

Guy.

Hello;

Do you add the flow aid straight from the bottle? The Liqitex flow aid I have says on the bottle to cut it 20-1 with water.

Bill