Working in very hot climate

Outdoor ambient air temperature is no factor unless you are spraying outdoors. If you are, you probably want to wait for that time of the day when it cools to more conducive temperature, below 80.

What is your humidity like? Any chance you can spray indoors in a more comfortable environment?

I would probably think you would need to make sure you thin your paints a tad more because the temp would mean they are going to dry faster. Apply several light coats instead of one or two thin coats for coverage. 

Also if that is the temperatures at which you are painting, take precautions to keep your hands off the model. Your body will be secreting oils and moisture which will transfer to the surfaces of the model while you are handling it...a cause for paint disaster. Wear gloves or use a holder of some sort.  

My AB booth is in an unheated/un-ac garage add-on. have problems in the WINTER/FALL when the temp goes under 65, but never when its "hot". I spray enamels.

The biggest issue, by far (at least in my case) is humidity. Since I paint (basecoats anyways) with enamels, I let everything cure 2-3 days. Just dont leave your model at the hot temp to dry out, plastic (specially trumpeters) are at times VERY meable, and can warp in the heat. I have a box (with a "holey" lid) I use to store what I AB during the summer, just set aside for a few days and work on something else.

I tested conditions by simply spraying primer on some ship hulls, and figured out the paint was coming out ok in the heat.

You didn't say what brand of paint you are using, but from the remark about running water through your airbrush, I assume you use acrylics. Don't use Tamiya or Gunze Sanyo, or any alcohol reduced acrylic. Use only water reduceable types (Polly Scale is a good one).

Secondly, use an acrylic retarder, probably about twice the normal amount (two drops per thinned airbrush cup) and reduce the paint more than normal. I can't give you a specific recommendation for thinning ratio or consistency—you'll have to experiment. You will probably have to apply numerous very thin coats.

Finally, airbrush at the lowest possible pressure, again, you will have to experiment, but aim for 10 psi.

As for the airbrush, keep a squirt bottle of Windex handy. As soon as  you are done, dump any remaining paint, wipe the cup, and blast Windex through the airbrush. Rinse with water.

Tip dry will probably be a problem. A cotton swab in a small container filled with Windex, then applied to the tip each time you stop (and probably occasionally while spraying) should clean the problem up.

Good luck! 

Triarius wrote:

You didn't say what brand of paint you are using, but from the remark about running water through your airbrush, I assume you use acrylics. Don't use Tamiya or Gunze Sanyo, or any alcohol reduced acrylic. Use only water reduceable types (Polly Scale is a good one). Secondly, use an acrylic retarder, probably about twice the normal amount (two drops per thinned airbrush cup) and reduce the paint more than normal. I can't give you a specific recommendation for thinning ratio or consistency—you'll have to experiment. You will probably have to apply numerous very thin coats. Finally, airbrush at the lowest possible pressure, again, you will have to experiment, but aim for 10 psi. As for the airbrush, keep a squirt bottle of Windex handy. As soon as  you are done, dump any remaining paint, wipe the cup, and blast Windex through the airbrush. Rinse with water. Tip dry will probably be a problem. A cotton swab in a small container filled with Windex, then applied to the tip each time you stop (and probably occasionally while spraying) should clean the problem up. Good luck!

I use Model Master Acryl. I don't know if its alcohol reduced acrylic or not. The reason I picked MM is they sell it at my local hobby shop.

 Scott

Scott, I don't use MM Acryl. From what I've read, it may be an alcohol reduceable paint. What you can try is to mix distilled or deionized water with the 90% isopropyl alcohol to slow evaporation rate.

To test paint-thinner compatibility, put a small amount of thinner in a glass container and add an equal amount of paint. Stir, then decant part of it on a glass or glazed ceramic surface. Look for persistent lumps, strings, or other things that aren't part of a smooth, uniform coating. If it looks good, it's probably a useable combination for immediate use. Cap up the rest of your test batch and let it sit for a few weeks, shaking occasionally. If it's still smooth after that, the combination is compatible.