Airbrushing for the first time...

What kinda paint and who makes it?

thin paint with isopropynal alcohol (if its acrylics)
mineral spirits if its enamal
lacquor thinner if its lacquor

In general paint viscocity needs to be matched to the pressure you are spraying at and your airbrush. You didn't say what you were using for an air supply; canned air, compressor, tank, etc. so this may not work completely for you.

Run your air pressure down to about 15psi. Thin the paint with about 3 parts paint to 1 part thinner, and try spraying it on some scrap plastic (or just cardboard in a pinch). If it doesn't want to spray or the airbrush "Sputters" add a little more thinner. If the paint sprays real thin and runny, add some more paint. Keep track of the percentages so you can use them again. I think that ratio and pressure will work fine since that's what I used with my Badger 200 most of the time.

If you are spraying acrylics you need to paint relatively close to the surface of the model; say 3" to 4" and keep the pressure low. If you are spraying enamels or laquers you can get by with more pressure and more distance. The reason is that acrylics dry so fast they will actually start to dry between the airbrush and the model surface causing a pebbly finish.

Thanks, I'm using a propellant can for now untill I can get a compressor, and how do I measure the ratios exactly? I tried once with a medicine cup but some of the paint dried up on the sides so it wasn't exact.

Paul,

Pick up a couple of eyedroppers at the drugstore and use them for measuring the paint and thinner.

Mike

how should i thin down acrylics for airbrush use, rubbing alcohol or water?

It depends. You are never wrong in going with the thinner that's made for the product i.e. Tamiya Thinner for Tamiya Paint. Alcohol will flatten Tamiya gloss paint. Alcohol works well for Tamiya flats and Gunze but is disasterous with Polly Scale. Use distilled water for that. For Model Master Acrylics Model Master Acrylic Thinner works best although you could use distilled water or windshield washer fluid if the thinner was not available.

Mike M

Most people have their own special elixir for their thinners.

I used to use Tamiya X20A for all my thinning, but given where I live, and freight issues, it became too expensive and tiresome to order, so now I use both distilled water and alcohol, in a 30% water/70% alcohol ratio. The water acts as a carrier for the alcohol because straight alcohol evaporates far to quickly to be of any real use with acrylics.

This is measured with glass eye droppers, or a syringe to keep it exact.

Then when cleaning my brush, I use alcohol straight.

I have never noticed my gloss finishes being flat when mixing straight alcohol as a thinner, might give it a go and see.

When I use enamels,I have some enamel reducer that I buy at a Automotive Paint Store.The last time I purchased it,I think it was around 12 dollars a gallon,which will last a long time.When I thin paint to spray from an airbrush,I thin it to the consistency of milk.Watch the next time you drink a glass of milk,when a stream of milk travels back down the side of the glass,I know it sounds silly,but thats how I judge when the paint is thin enough,Let some of the thinned paint stream down the side of the side of the airbrush paint jar and look for the consistency of milk.It works for me everytime.Hope this helps.

QUOTE: ... When I thin paint to spray from an airbrush,I thin it to the consistency of milk.

Good point, Paul. That's the common means of judging the correct consistency, and it's usually about right. It varies with the type of paint, airbrush, pressure, and distance from the surface, but in general that's usually a good rule of thumb.