Any proven tips on how to REALLY slown down the drying time of Tamiya paints?

I don't know what your thinning with,but don't use alcohol,try Tamiya Lacquer Thinner,it works well.

I only use Tamiya's Thinner when I airbrush their paints. Other thinning mediums usually lead to tip dry with their paint. I have not tried their lacquer thinner for airbrushing.

Have you tried using retarder? I use the acrylic retarder from Winsor & Newton's Galleria line, but other brands should work as well (yes, even with Tamiya paints). You want a liquid retarder, not the gel kind.

I mix the retarder into some Tamiya acrylic thinner, about 1 part retarder to 9 parts thinner. When I do, no more tip dry.

You didn't mention what kind of airbrush you are using, but I would use the biggest needle/nozzle combination I have.

I have been told that Tamiya acrylics are a different chemistry from most others.  Anyone really know for sure what the chemistry is?  I know there are things called acrylic enamels and acrylic lacquers, and most acrylic paints are just called "acrylic paint".  Is it the solvent they use that is the difference?

I've used Tamiya acrylic paint with zero issues of tip drying out. Like Stik, I use Tamiya's brand thinner when airbrushing. I don't add any retarder to Tamiya thinner whatsoever. Your best bet is use the brand thinner to the brand paint you're working with.

I love Tamyia paint, as everyone else here has said, use Tamyia thinner then I add 5 or 6 drops of retarder. mix well then spray, paint goes on smooth and does not dry out on brush tip.                   ACESES5

In my experience, most Tamiya paints can be leaned out very thinly as they have a very high pigment load (Notable exception, gloss white). Tamiya acrylics excel when mixed thinly and applied in multiple coats.

I think many people tend to under-thin when using Tamiya acrylics, as I often see recommendations of 2 parts paint to one part thinner, perhaps for fear of lack of coverage. I often thin to 3 parts thinner to one part paint, sometimes more, sometimes less, depending on what I want to achieve. I've not had any appreciable incidence of tip dry, using a 0.35mm airbrush.

The "drying trail" effect you often see when airbrushing flat paints, the wet trail which flash-dries in a few seconds, right before your eyes, is exactly what you want with this paint. Once flash dried, you can apply the next coat. Build the depth up with multiple thin coats. That's the key.

The exception to this is Tamiya's metallics, in which the particles of metallic pigments are quite large compared to many other paints. If mixed too thinly, they will settle quickly and clog your airbrush. If it's a coloured metallic, the metallic pigments and the colour may separate. Finding the ideal thinning ratio for metallics is a matter of experimentation, as airbrush setups & pressure settings can vary greatly.   

Now all that being said, if you really do want to extend the drying time of the paint, Tamiya makes their own retarder, or as already mentioned, you can use Tamiya lacquer thinner, which will slow the drying of the paint (actually very helpful when using gloss Tamiya acrylics) or use one of a number of artists acrylic retarders which are available.

Don Stauffer

Is it the solvent they use that is the difference?

The solvent used does not make any difference to the basic chemistry of the paint binder, which uses acrylic polymers to form a coating. This is what determines whether a paint is acrylic or not. The solvent is irrelevant.

That is great stuff Phil! I generally use Tamiya thinned pretty well. Either the x-20a acrylic thinner or lacquer thinner is good, no tip dry from a Badger 105. I find the lacquer thinner sometimes leaves a somewhat rough finish with Tamita flat paints though.

REDUCER is your friend! This is what they use in automotive shops to lengthen the drying time. Lacquer thinner is only going to force it to dry faster. The Methyl Ethyl Ketone is hot, and acetone is a dryer which flashes off very quickly. This is counterproductive if you're looking to extend the drying time of your paint. Lacquer is not an acrylic product although there are those manufacturers out there that will put it on their label. They wouldn't know true lacquer if they were DROWNING IN IT!! Lacquer is made from nitocellulose fiber, and cannot be used with acrylic products as the two are chemically incompatible. This will leave you with a surface with tackiness, and wrinkles all over it that won't cure completely!

The only difference is that this acrylic is made with a styrene base which is hotter than the enamel version that is mixed with acrylic monomers to bind the paint with the solvents, and pigments more strongly that it can with by itself. The tulol which is what you mainly smell in regular jar and spray paints is also hot much like xylene but not as hot - this is a chemical stabilizer that they also put into model glue. Often called oil of mustard it reduces drying time once opened, but you can get this, or toluene which softens plastics and you have to be careful using it will hasten drying time. Most of these you don't want to use unless you're familiar with them, or are a trained professional. With the exception of solvent based paints you can clean most acrylics with water. That would extend your drying time. You can use reducer with most solvent based paints without crazing (whitening) of the paint once dry, or leaving it soft to the touch forever. If you use too much reducer it will take forever to dry, or it may not dry at all! It sounds more like you need something to HASTEN dying time if you need to paint a lot of panels. In that case you don't want to cut your paint or reduce it. You'll need a hair dryer to make it dry faster if you need to mask a large area. Acetone dries fast too and it's inexpensive enough that you can get a quart of it at Menards for around $4.50. It goes a long way too! I use it to remove super glue from the bottle tip, and the cap when it gets gummed up.

~ Cobra Chris