I know this question has come up a million times but I'm too lazy to read through 3 months worth of threads to find the answer.
I'm going to use Model Master ACRYLIC paints for the very first time on my P-40. I've only ever used enamel so I wanted to know what ratio to use ( paint/water ) to get the best results.
The guy at my LHS said to mix 50/50 water and alcohol and then use that mixture to thin down my paint but he didn't say what ratio to use for thinner/paint.

Thanks,
Hermon

Hi Hermon!

I use an aztec Airbrush and mainly Tamiya Acrylics. I mix usually 2 part of paint for 1 part of thinner (Tamiya X20 or water) for the overall colors and approx. 50/50 for the details or mottlings (Luftwaffe camo for example).
Best, as always, is to test on a piece of plastic first...

Jean-Luc

Hi Hermon
I was looking into this a few days ago and came upon this article on a website all about using airbrushes - I'm going to try these ideas on my next project.

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Interesting tips on thinning acrylics but ignore or delete this if you like.. but I've found most modelers like to learn as much as they can about the mediums they use
I've also found that the modeling world is suffering from a lack of knowledge about using acrylics and many sites propagate false information like a snowball. Acrylic does not mean water based..thats a big misconception (From ArtLex.Com) Acrylic paints - Synthetic paints, with pigments dispersed in a synthetic vehicle made from polymerized acrylic acid esters, the most important of which is polymethyl methacrylate.

My main gripe is what people commonly recommend for thinning acrylics.

Before you mess with anything or add anything to a paint, test it's individual properties first. Put a drop on a piece of glass. This test will allow you to see the properties of off the shelf additives you might want to try..How quick do they dry. How flexible do they dry, how clear, do they have any adhesion or just shrink and lift...? For example, something that goes on paper must be flexible, something that goes on a hard surface must be hard and have good adhesion.

The biggest breakthrough I have made lately is to always use an airbrush medium when thinning acrylic paints for airbrushing..Think about it, water, alcohol, washer fluid, glycerin, grandma's recipe, do not have any bonding qualitys.

And the cheaper or thicker the paint the more important medium becomes.

Airbrush medium contains acrylic polymer. Acrylic polymer is basically clear acrylic paint. What I’ve found even more useful is that it contains specific additives designed to retard drying time, improve the flow of acrylic paint through the airbrush, thus decreasing airbrush clogging and preventing paint build up around the airbrush tip. A real problem especially if thinning non-airbrush specific paints.

Acrylics cure by the linking of acrylic polymers into long molecular chains. If too much water, washerfluid, soap, alcohol, etc. is used, the acrylic is "stretched" too far and can't form proper links. It will typically dry too rapidly and leave a rough finish. The airbrush medium contains acrylic polymer in order to guarantee that there is sufficient acrylic present to properly link and form a strong paint film. If thinning with just water ,washerfluid, alcohol the odds of the paint lifting or chipping are high because unlike other additives, the acrylic polymer in the medium doesn't evaporate and thus acts like a clear paint.

So while it’s ok of course to use tiny quantities various non-bonding liquids for thinner, it’s just as important to regain strength, flow and sprayability with some airbrush medium. It’s somewhat expensive but a bottle goes a long way.

I use Liquitex airbrush medium, since it is readily available at Hobby Lobby. It has finally made using alternatives like thick craft paints a reality for me with excellent sprayability. And leaves a smooth texture.

If I find that adding medium has not made the paint thin enough before loosing the richness of the color ONLY THEN, do I add a little distilled water. And only distilled water rather than all the wacky stuff most people recommend.

These are some common airbrush mediums

Blick Polyflo
Createx
Golden
Jo Sonja's Lascaux
Aquacryl
Lascaux
Liquitex
Pebeo
I'll stop here.. If you really want to learn more about airbrushing acrylics check out the "Golden" website..it's very informative!
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Hope this helps. The whole article (and others, on things like air pressure etc) acn be found here:


http://www.craigcentral.com/models/thinning.asp

Steve

Thanks guys!
I haven't had time to try the new paint.......too much work to do, but I'll take your information and put it to use.
The only reason I use enamel in the first place is that my LHS carries all the colors I need in enamel. Today though, the colors I needed for my P-40 he only had in acrylic.
Jean-Luc, do you ever run into problems using Tamiya paint when searching for the right color? I've noticed that at my LHS they only carry about 30 different colors of Tamiya and almost none of them are the standard military colors like "dark earth" or any of the German colors. Do you end up having to mix your own or what?
Hermon

Very useful: Tamiya Paints Site

Particular mixes: http://www.dana-nield.com/tamiya/forum.asp?FORUM_ID=4

Hi Hermon!

Yes, Tamiya don't have a big range of colors. At least not as big as modelers would like it to be! :-) That's why it is asked to mix their paint in their instructions.
Here's an example: I needed US Interior Green for the T-6 Texan I'm currently buidling and Tamiya doesn't have this "particuliar" color. I looked in one of Tamiya's P-51kit instructions and it was written to use 3 parts of Yellow (XF3) and 2 parts of Green (XF5). I made the mix in an empty jar and now I have my Interior Green for many other projects.
I have about 60 different Tamiya acrylic paint references and about 20 "home made" colors. With every new model, new colors are added and now I have Luftwaffe early colors, US Navy grey and blues, French pre-war, WW2 and post-war colors etc...
You said your LHS has only 30 different Tamiya colours? That's not much, it should be 80 for the acrylic range!?

Jean-Luc

I use mainly Tamiya Acrylics and Humbrol enamels. My basic paint to thinner ratio for both is 2 parts paint to 1 part thinner. Now this is my basic mix. I test spray onto a plastic bag and if it sprays OK I then use it on my model if not I either add more thinner or add more paint testing each on a plastic bag until it is right.

Cheers
Cliff

Model Master acrylics are my default paint of choice. I never thin with water when I'm AB'ing them, though. I thin with alcohol and/or Windex. Windex is a great wetting agent, which slows the drying time and prevents clogs. Alcohol speeds the drying time. Usually, I thin about 1/3, 1/3, 1/3, and shoot at fairly high pressure (25-35 psi). The Windex prevents jams/clogs/spattering, and the alcohol (and high pressure) means that the paint is dry almost the instant it hits the model.

I always found that water-thinning led to clogs (I could rarely get through one entire coat on a model before having to partially disassemble the AB for cleaning). And I find that shooting a little straight Windex before I begin priming makes the inside of the AB "slick," and makes cleanup afterward really easy.

Seriously, give these two thinning agents a try - you may never go back to water (or enamels).

Ok I hope to start painting with my acrylics this weekend. Everyone keep your fingers crossed.

I won't have time to swing by the LHS so this time I think I'll try the alcohol/water or windex/water method.




Hey Jean-Luc,
Since you have spent all those hours putting together references like that it would be a shame and a waste if you didn't share that knowledge with someone else.....someone like me perhaps.

Hermon,
You might find this series of articles useful (and everyone else too ) which I have found invaluable from the Swedish IPMS site. It goes through the colours used by most major airforces, across all time periods and discusses how to mix them in the major paint manufacturers.

http://www.ipmsstockholm.org/colorcharts/colorcharts.asp

All the best

Steve

Hi Hermon!

I would like to give you those informations but I'm afraid they are secret!
More seriously, I don't mix in a "mathematical" manner. I do trust my eyes even if this is not very recommended... but I can use my Tamiya kit instructions to make a list if you want. The list won't be complete but a least you would have some references...

Jean-Luc