Airbrushing Temp Problem.

I agree with Drew, it's likely the paint is drying before it has a chance to get to the model. Spraying outside has it's challenges, as you've no doubt discovered. Here are my suggestions:

• Reduce the amount of thinner, try 25-30% thinner to paint. Tamiya thinner is essentially Isopropyl Alcohol, and that flashes dry very rapidly, which causes the undesirable texture and loss of gloss.
• While Tamiya thinner also includes some acrylic retarder, it probably isn't enough to combat the heat you experience in the summer months. As Drew said, add some acrylic retarder to help slow the drying time down. Mix it with the thinner before adding it to the paint.
• DON'T spray in the direct sun, try spraying inside a cardboard box. The shade created will help lower the temperature.
  
• Lowering the air pressure and getting closer to the surface will help, but if your AB is the external mix siphon fed Paasche, getting below 20psi is going to be problematical.
  
• Gloss is certainly a much more difficult surface to achieve those much desired surfaces. I've successfully sprayed the Tamiya Gloss Red without issue, so it IS possible. Mind you I have a booth inside a fairly cool basement, which helps!

I dealt with ambient temp trouble all winter.....mainly being too cold in my basement! 13 C is about 58 F, I think.....and I seem to have good luck at that temp and higher. One thing I notice in your post is the 22psi. That seems quite a lot to me.

Most recommendations I've read state a pressure in the mid-to-high teens. 16-18 works well for me with acrylics. Of course it depends on your equipment, too.

Though it sure sounds like your paint is drying before landing. 

What type of store's stock acrylic retarder/slow dry? Im not 100% sure what it is so I dont know where I can get it.

The leading hobbie store here in Sydney doesnt have it.

roylo wrote:

What type of store's stock acrylic retarder/slow dry? Im not 100% sure what it is so I dont know where I can get it. The leading hobbie store here in Sydney doesnt have it.

Hi Roylo,

The only acrylic retarder I've seen around Sydney is the "Jo Sonja's" branded one, labelled "Retarder Medium". I've found it at Riot Arts and Crafts stores and in the crafts section at Bunnings (though it appears to be a "dead" stock line there and may be hard to find). It should cost somewhere around $10-12 for a 250ml bottle, which should last you for many years.

PS: Many hobby stores in Sydney have just restocked on the 250ml Tamiya acrylic thinners (I was told they havn't been available for a while) - if you're not using the "economy size" thinners, grab one or two (about $10 each) - 250ml of the same stuff in the 10ml bottles will cost about $75 here.

Thanks for that yep I already have a 250ml bottle.

Gee sure is alot of mucking around to get the red gloss to come out how it is supposed to. I mean Ive tried varying everything. Use Tamiya thinner, tried all different thinning ratios from 80% thinner to none at all. Tried all pressure ratios and the only thing that will give me a glossy finish is spraying at 13 Degrees C, not higher.

I've found in the last few days, the less thinner I use, the grainier the result. Try 60% thinner/40% paint, reduce your air pressure and get up close and personal.

Now this goes "against the grain", but you want to slow the initial drying of the piece. Put it in an airtight container (eg. a food storage container) and leave it for about an hour or so. You may find that it helps to level the paint and smooth the graininess.