Paint Measure

Here is something I came up with to measure small amounts of paint and thinner.


A small hypodermic syringe, a standard glass eye dropper and a short piece of aquarium tubing with an outside diameter of 1/4 inch.  Not all aquarium tubing is this size, and it must fit snuggly in the eye dropper and the syringe.  The syringe is marked at one cm intervals, and each interval corresponds to 7 drops.  When the plunger reaches the highest mark, the eye dropper will be almost full.  In use, I never exceed this mark, and the syringe and tubing are never touched by paint or thinner.  I have found that the rubber seal in the syringe swells when hit by lacquer thinner and becomes wedged in place.  To clean the dropper, I replace the syringe with a standard rubber bulb.

This may seem somewhat anal, but I hate to waste paint and I have become pretty good at estimating the amount that I will need for each session.  I mix paint and thinner right in the airbrush cup and never pour thinned paint back in the bottle.  I've had paint turn to jelly after doing this.

Before spraying paint, I backflush by covering the nozzle of the airbrush with a wad of paper towel, pressing the trigger for air and GENTLY pulling back on the trigger to make bubbles in the cup.  This ensures that the paint and thinner are well mixed.  If you try this with a single action brush, be sure to screw the needle all the way closed before pressing for air, or you may create a paint geyser.  Back the needle off slowly to get bubbles.

Thinning

I should say something about thinning.  The instructions on a bottle of Testors Model Master Airbrush Thinner say to thin 3 parts paint to 2 parts thinner.  I read a thread on the Britmodeler forum here where a fellow who used to make a living painting cars wrote that paint should be thinned as much as 1 part paint to 9 parts thinner.  The most common advice is to thin to the consistency of 2% milk.  I think the truth is that there is a wide range of thinning that will work depending on your technique.
 
A lot of people thin Model Master enamel 50/50 with lacquer thinner, and it has always worked for me.  If you're going for really fine lines or your brush has a really small nozzle, you may have to thin more.  You are the only one who can determine what works best for you.  I use regular hardware store lacquer thinner with no problem.  But, I have read that lacquer thinner can contain a variety of solvents, so I can't guarantee that they will all perform as well.  Some people use mineral spirits with enamels, both for painting and cleanup.  The only drawback I can see is that it would take a bit longer to dry.  But, maybe that could be a good thing, and the fumes wouldn't be as bad.  Testors airbrush thinner is about 50% mineral spirits.

A common question on forums is: "What should I use to thin Brand X paint?" or "Is it OK to use Liquid Z to thin Brand X paint?".  Of course it's always safest to use the paint manufacturer's own thinner.  But that can be a bit expensive, and people like to find cheaper alternatives when they can.  And it's really pretty easy to find out for yourself if something is going to work. Just put a couple of drops of the paint in something like a small saucer.  Then add a couple of drops of the thinner you want to try.  Stir it around.  Does it mix well, or clump up?  If it looks OK, let it dry.  Does it dry OK in a reasonable time and does it harden up OK?  If it passes this test, try some in your airbrush and see how it sprays.  But remember, whenever you are trying something new, like a different thinner, it's safer to try it on junk plastic first.

Decanting Spray Paint

 
I don't like using spray paint directly from the can because it goes all over the place and is difficult to control.  I guess the airbrush has spoiled me.  Anyway, I do occasionally decant it and use it in my 155 and I've never had any problems with it.
It's already pretty thin and can be sprayed without further thinning.  I clean the brush with regular lacquer thinner.  I won't try to explain how to decant it, but instead direct you to Brett Green's video, which does an excellent job.    Be sure to look at part 2 also.



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