Hello everybody! Just a (sort of) quick question and hopefully some speedy answers. It’s about 50 degrees Fahrenheit and 64% humidity here on the Eastern Seaboard. I’d really like to spray my JS-3 with Testors Dullcote aerosol, so I can work on it tommorow afternoon. I’ve heard a lot about problems with matte varnishes and humidity, but not anything about problems directly related to temperature. Can I spray it outside, or will the temprature affect it? I’m planning on taking it to the basement then for off-gassing, so it’s not like it will be outside for a long period of time. Any help or advice?
I have found that using a CO2 cylinder helps keep water out of the line when airbrushing in high humidity. But, you need to be careful not to get water under the paint to form what is called blushing.As far as the temperature goes, make sure the paint is warm and cure the paint at room temperature otherwise it will develop marks when handled, sanded, etc…
That’s room temp for 48hrs enamels and 24hrs acrylics.
In blushing, the water comes from the atmosphere. Blushing occurs with very volatile solvents like lacquer thinner. It happens when dewpoint is only a few degrees below ambient. When a liquid evaporates from a surface, it cools the surface. It may easily cool the surface below the dewpoint, and water from the atmosphere then condenses on the surface, making it rough. Just don’t spray lacquer on damp days. Enamel thinner is not that volatile. I know folks who thin both enamels and acrylics with lacquer thinner. They need to worry about blushing.
I’m assuming you’re talking about “rattle-can” Dullcote? In my 30 years of using Testors Dullcote, I have found that it dries best (and flatter) when used in direct sunlight; I am to the point where I save up my “flat jobs” for sunny days, and do them all at once. I’ve tried using Dullcote on cloudy/cooler days (when I was deperate), and it always ends up coming out semi-gloss, instead of flat.
JMorgan’s on the right track; make sure both the model and the paint are warm-ish before spraying. The simple act of spraying the clear flat will cool it down, partly because it’s decompressing (gasses cool down rapidly when decompressing), and partly because it’s traveling through the (cooler) air before it hits your model. Leave your model sitting in the sun for a few minutes before you spray it, that will help.
You could probably try applying it under a heat lamp, or another source of heat, but don’t get it too close! I ruined a perfectly good F-111 a few years ago by getting it too close to a 500W halogen light.
Wow, lots of zombie threads today! Someone was doing a lot of digging 
This thread was intended as a preventative query before I tried to spray the Dull-Cote. Since I didn’t get a response at the time, and I wanted to spray before the weather turned foul, I decided to wing it. The Dull-Cote turned out fine, and the model is now finished.
Well, you are a MUCH faster model builder than I! I’d still propably be figuring out how I was going to paint it!
Lol, that’s when I’m motivated. I’ve barely touched my entry for the 1946 GB [bnghead]