Does Humidity Greatly Effect Painting/Airbrushing?

[modelling muppet]

G'day again,

I have just started using my Aztec airbrush for the first time, and I'm just in the stages of getting a feel for it, but I live in a humid climate. Does this have a great impact on painting? And is it better to use enamels or acrylics (I use acrylics). Also a side question, how do I drybrush with acrylics as the paint tends to 'clog up' as soon as I apply it.

Cheers,

Muppet

[The Loggie]

G'Day Muppet. To answer your questions.

Humidity - should not affect spraying IF your compressor has a air filter / drier between the air intake and the spray gun. Preferably, this should be between the compressor and the collector tank. A second one between the tank and the gun is not necessary, but a luxury. These'll condence the water vapour out of the compressed air, and back into liquid water. Tap the water off after each days use. This'll stop it rusting the inside of your collector tank, and from getting into the paint. Humidity (esp HIGH) makes it uncomfortable (for you) to spray.

Enammels vs Acrylic. 45% of sprayers like enammels, and 45% like acrylics. The other 10% use both (acrylic on top of enammels, not vv. Enammels on top of lacquer paints). I'm in the 10% though I use mainly Tamiya & Gunze acrylics. Do not mix the two in the one pot 'cos they do not like eachother. Enammel is an oil-based paint and acrylic is a water-based paint. Oil & water do not mix (check-out some cooking oil in water). I learn't that acrylics can be brushed, but they have to be thinned with metho or a similar thinner (40-50% thinner). They clog-up because the top layer dries quickly, but underneath dries slowly. So repeated brushing merely lifts the dried surface skin. I successfully brush-paint and dry-brush with Citadel Miniatures acrylic paint. They are designed to be brushed. This with ONE DROP of PLAIN tap-water per bottle.

Hope that this helps you. George, out.....................

[kenlilly106]

High humidity can also effect the drying times of gloss paints, moreso with enamels than acrylics.

Another problem is "blushing," where moisture is trapped under the paint, normally seen more with clear coats than colors, only way to avoid the problem is not to spray in humid conditions.

As far as the enamels v/s acrylics question:

Use what you're the most comfortable with and what you can get the easiest.

Ken

[William G]

Another effect is Fisheyes

where you have a droplet of water under the paint that causes a slight lens look or effect.

In some areas it is wanted (like making a paintjob on a car look wet... real wet But not on a clear coat of future or any kind of clear...

William G

[modelling muppet]

Thank-you heaps guys. I value your opinions and help. This forum site is very helpful and it's good to know there are others out there that are happy to impart thier modelling wisdom on the new comers to the hobby. Cheers,

Muppet

[Fishwelding]

My experience is that provided you install moisture traps as Loggie described, you should be able to shoot enamels and acrylics.

But experiment with different paints in different conditions. With acrylics, I found that in more humid conditions, I was better off shooting paints thinned mostly with isopropyl or 'denatured' alcohol. In less humid (wintertime in Mid-Atlantic United States), I use Tamiya's proprietary thinner. Tamiya's thinner also seems to cut down on the acrylic paint clogging in the brush, but if the problem persists, several folks here can suggest brands of chemicals sold as art supplies that they add to the paint.

Edited December 11, 2007 by Fishwelding

[Big Kev]

My experience is that provided you install moisture traps as Loggie described, you should be able to shoot enamels and acrylics.

But experiment with different paints in different conditions. With acrylics, I found that in more humid conditions, I was better off shooting paints thinned mostly with isopropyl or 'denatured' alcohol. In less humid (wintertime in Mid-Atlantic United States), I use Tamiya's proprietary thinner. Tamiya's thinner also seems to cut down on the acrylic paint clogging in the brush, but if the problem persists, several folks here can suggest brands of chemicals sold as art supplies that they add to the paint.

It's my understanding that one of the benefits of Tamiya's X-20A thinner is that it contains an acrylic retarder that helps slow the otherwise rapid drying time of some acrylics. This would certainly help in hot, dry climates. In more humid climates, rapid drying times probably help combat blushing and other moisture-related problems.

Kev

Edited December 11, 2007 by Big Kev

[Chuck1945]

Others have already covered humidity issues, I just want to add a couple of additional observations regarding dry-brushing acrylics. I choose to use acrylics because I do not want to endure the fumes and smell of the various thinners (both enamel and lacquer) associated with using spraying enamel (or solvent based lacquers) paints. Acrylics however, as you note, dry quickly making dry brushing problematical.

I originally purchased some artists tube type oil paints (white, black, and raw umber) for weathering, shadowing, etc. I now also use these oil paints for dry brushing and just recently added tubes of water color in red and yellow to my collection. These work fine in cockpits (where I do 99.5% of any dry brushing applied to a model) since there is little chance the water color will be rubbed off due to handling. The water colors have the additional benefit of being removable with a brush full of water should I so desire.