Help Air Brush Meltdown

Windex should work as a paint remover for acrylics.   If that doesn't do the trick,  Easy-Off Oven cleaner is a good thing to totally strip the model and start over.

Off-hand it sounds like your air pressure was too high, rather than the paint being too thin.   The recommendation is to thin the paint to the consistency of skim milk.   You want to spray at 10 to 15 psi.

Most of all you need to practice.   Start with a sheet of cardboard.   Mix the paint to the desired consistency.  and spray a bunch of lines.  Try for consistency.   Now vary the distance the airbrush is held from the surface.    Now vary the air pressure,   then vary the paint consistency.    Now take a junker model and paint it.    Make mistakes and see what happens.   Once you understand how your airbrush behaves under different conditions you can then use it to paint your latest "good" model.    It is really not recommended that you use a new tool on your latest masterpiece without practicing with it first.

Welcome to the rewarding and challenging world of airbrushing! As you've discovered there can be more challenges than rewards at first! Don't panic! With practice, practice, practice and oodles of patience you'll get the hang of it. Consider sacrificing a cheap model as a test bed to practice on.

The Crescendo is a decent airbrush with a chunky body for big hands, lots of people use them for modeling. The only thing with them is they can put out a LOT of paint at full bore, as they were designed more for T-shirt painting. You'll have to learn to use restraint, and remember that all airbrushes can put out more paint than you want, and in place you don't want it!

Unless you plan on building 1:72 German armor which requires incredibly thin lines, you should get years of service from the Crescendo. The Crescendo does have interchangeable needles and head assembly for fine, medium and large. You'll probably have the medium which you can identify by counting the rings on the butt end of the needle: 1 for fine (pencil thin to 2"), 2 for medium (1/32" to 2 1/2") and 3 for large (1/16" to 3"). Large is just too coarse for modeling use with the exception of spraying metallic paint as a flood coat. Medium would cover 90% of most people's painting, with the fine being useful for pencil thin lines. I find that siphon fed airbrushes, while capable of spraying thin lines, require so much more air pressure to "pick up" the paint that over spray becomes an issue. If extremely fine lines are in your future, then consider trading in the Crescendo on the 100LG or 105 Patriot. Their gravity fed design allows for finer control, as the air pressure can be lower.

Go and buy the biggest jug of Ammonia based window cleaner you can find, it doesn't have to be Windex brand, but it does need the Ammonia. "Green" cleaners won't work. Then fill a container just large enough to  dunk the model in to soak. It should come off pretty easily. Save the "dirty" cleaner to re-use in the future. You WILL need it again! Remember to wash off any residue, and I suggest wiping down with Rubbing Alcohol (the purer, the better), before re-painting.

There is no "Perfect Formula" for thinning, as air pressure can be adjusted to compensate if the paint if too thin or too thick. You also need to take into consideration what it is you're painting. Thin lines require thinner paint, as it is easier to control over spray.

Most people try to thin to the consistency of 2% milk, rather than use a strict formula. Get a glass and put a bit of milk in and pretend you're a wine connoisseur and roll the glass around to watch how it clings to the glass and the time it takes to settle and then thin so your paints do the same. If I was to put a ratio to it, 60-80% paint would be the range to work with. You'll find that lighter (less opaque) colors require less thinning, and darker (more opaque) colors can stand with more thinning. Be careful not to thin too much paint. It doesn't last as long, once thinned.

MusicCity has written (and collected) some great articles on airbrushing and is worth your time to read through. After admiring his collection of warbirds, scroll down to the bottom of the page for the articles. Pay particular attention to the article on cleaning. An improperly cleaned airbrush quickly becomes a problem. One thing I recommend is buying a jug of distilled water. Far too many communities have hard water, and the last thing you want is mineral deposits clogging up your airbrush!

And don't be afraid to ask more questions. The collective knowledge of the members here is astounding!

Tamiya recommend thinning -  3 paint : 2 thinner , this works fine for me when using Tamiya acryic thinner.

All of the above is good advice.

You can also use denatured alcohol to remove Tamiya acrylics. It will remove the paint very quickly, with no effect on the styrene.

If your paint is running, it's more likely to be either too much trigger (paint flow) and/or too high an air pressure at too close a distance.

What are you using as an air source? If you are using a compressor, for a siphon feed brush like the Crescendo, I'd suggest about 15-18 PSI and work from there. Go much below that range and you may have problems with paint "draw" from the jar and perhaps reduced atomisation, causing spatter. If you're using "canned air", it will be difficult to regulate the pressure and you will need to concentrate on regulating the paint flow using the trigger.

I doubt that your paint is too thin. I often airbrush Tamiya acrylics up to 75-80% thinner to 25-20% paint. Tamiya paints have a fairly high pigment load and can be thinned quite considerably. The key is to apply multiple thinly applied coats. Never try to achieve "one pass" coverage.

Oh, and PLEASE, tell me you're not thinning with water. In very small amounts, it's ok, but more than about 10% and you will be breaking it down, leading to poor adhesion and a chalky finish.

EdGrune

You want to spray at 10 to 15 psi.

Not with a siphon-feed like a Crescendo as that is too low of pressure to reliably atomize and feed the airbrush as has been mentioned by others. I would say 20 psi at the lowest for the most part. The Crescendo can really put out the paint and is Badger's best airbrush for the heaviest coverage followed closely by the 155 Anthem.