just a few weeks ago. Go herehttp://www.hyperscale.com/2009/features/fw190a8tam48ms_1.htm
for an excellent article by Marty Sanford on how he built and painted Tamiya's FW-190. He explains his painting technique in detail (and he was tutored by some of the best), and the amazing thing is the quality of the results he was able to get using a "humble" Paasche H external-mix airbrush! I'm surprised nobody has mentioned this article - it was really informative and Marty's FW was just gorgeous. Frankly, it's one of the best articles I've seen on the subject in awhile.
There's some great - no, scratch that - some EXCELLENT advice here in this thread. I can't disagree with anything that's been said: thin your paint down much more than your normally would, lower the air pressure into your airbrush, get in close, and practice, practice, practice. I also second the idea that you view Floyd Werner's excellent DVD on building and painting Hasegawa's Me-109G. I bought Floyd's video when it came out, and I still find myself viewing it - and skipping around from section to section - every few months. It's both educational and
inspirational, too. English modeler Jeff Ilsley has a couple of good DVD's out too; one on general airbrush techniques, and another on military aircraft camouflage, with an emphasis on Luftwaffe WW2 paint schemes.
There's also some references available on the web that might help you. In Hyperscale's video series (viewable on YouTube as well) there's a couple of short films by Brett where he demonstrates how to apply a dappled Luftwaffe- type camouflage, as well as a good interview with Chris Wauchop where he describes - albeit much too briefly (we want to know EVERYTHING, Chris!) - his painting methods. I also suggest you check out Jean Barby's article over at STORMO! where he describes how he applies the intricate mimetic camouflage to his Regia Aeronautica models (go herhttp://www.stormomagazine.com/Articles/HowTo_JB_1a.html
For what it's worth, my own progression was a lot like G. Boyd's. The first model I ever airbrushed was a Matchbox 1/72 Bf-109E Trop that I painted back in 1980 with my then-new Badger 200. I followed the instructions - and the advice I'd gleaned from IPMS members, my local hobby shop, and a few good books - scrupulously, and got a surprisingly good result. And with Humbrol enamels, to boot! From that point on it was all downhill, at least for awhile. I had several years where I couldn't seem to get the combination of airbrush, paint, and thinner right for the circumstances. I even spent my hard-earned (for a teenager) wages on several other airbrushes in an effort to find a solution. Now, though, I realize it was all just "operator error".
After about five or so years of frustration I went back to the basics - paint, thinner, distance from subject - and my work began to improve. I did go through a phase where I tried to measure out paint and thinner in "exact" ratios using various tools - eyedroppers, pipettes, graduated cylinders - only to learn that while recommended mixing ratios are a great *starting point*, you're almost always going to have to add just a bit more thinner, or a bit more paint, to account for whether you're spraying small, fine lines and dots - like mottling - or area coverage, and to accomodate different brands and types of paint, different reducers, and factors like temperature, humidity, and air line pressure. I completely agree with the other comments in this thread; where airbrushing's concerned, experience and continued practice are the best instructors. Practicing on old "scrap" models or on three dimensional surfaces like pop bottles helps, as does simple practice exercises like spraying dots, lines, and squiggles on waste pieces of card or heavy paper. This kind of training is a staple of art schools and classes for professional artists, and it's equally essential if you're going to paint dappled or mottled camouflage schemes.
Other miscellaneous advice:
Solvent-based paints seem to work better for fine work than do acrylics. You'll note that in the article by Marty Sanford, while the large areas of camouflage were painted with Tamiya acrylics, he painted the mottle on the FW-190 with Model Master enamels. I admit that I have gotten very good results with Tamiya and Gunze acrylics, using their proprietary thinner, but I find that I get even better results if I cut them with an acrylic lacquer thinner like Gunze's "Mr Color Thinner". I can also do fine work with Polly Scale and Lifecolor, cut with proprietary reducers or with distilled water, but I find that they both work better if I add a drop or so of Liquitex Flow-Aid or Golden's Acrylic Extender, and even then I have to stop periodically to clean the needle and tip with a swab dampened with thinner. "Tip dry" seems to be endemic to water-based acrylic paints - even the professional artists complain about it.
On that note, even if you are using solvent-based paint, keep a thinner-dampened swab handy and periodically clean the tip and the end of the needle. When you're doing fastidious and time-consuming work, stopping occasionally to rest your hand, flex your fingers, and clean your airbrush really improves your results.
For fine work like mottles and squiggles, you have to thin your paint much more than you would for area coverage. A good starting point seems to be a ratio of 70:30 thinner:paint. Adjust the mix from there depending on conditions. Keep a panel of scrap cardboard handy while you spray your model. Shoot a few lines or dots on it after mixing up your paint but before applying it to your model. You can use this "test card" to fine-tune your paint:thinner mix, line pressure, and distance from the surface. I keep some old laminated card CBOE options calendars handy for testing, and periodically stop to check my paint mix and pressure while I'm working. If you're working through a long session, you may find that the pigment has settled out in your paint reservoir or your airbrush while you've been working, or that some of the thinner has evaporated (a problem with solvent-based paints), so you may need to stop from time to time to give the reservoir a swirl or adjust the paint-thinner ratio.
If you've got a compressor, get a regulator. An adjustable pressure regulator is one of the most important aids you can buy, especially if you intend to to fine, close-in work. To do fine work, move in close where the cone of atomized paint produced by the airbrush is finest. Be prepared to work as close as 1cm - or less - from the surface of the model. The downside of working in close with heavily-thinned paint is that it goes on very
wet, so you also have to adjust the line pressure into your airbrush to avoid getting "spiders", runs and puddles of wet paint. Reduce the output pressure on your compressor or propellant can down to below 1 bar (14psi). Many modelers work at pressures as low as 7 to 10 psi. Less pressure = less paint flowing through the airbrush.
Don't try to build up each blob or squiggle in one shot. Work slowly. Go over each mottle several times, gradually building the paint up in layers. If you look closely at pictures of Luftwaffe machines, often the mottle on the fuselage sides was sprayed loosely over a wide area, and the more prominent spots of color were simply those areas that received more than one pass with the paint gun. And don't be afraid to retouch or repaint areas. You'll often find that you have to tighten up a "blob" here, or reduce the coverage of a darker color there, or soften the edges of an area where paint pooled, or that you've simply got "too much" RLM 75 grey in one area or another. As Marty Sanford suggests, you can use a light, broad overspray of the HEAVILY thinned base color to "soften" the contrast between the mottling and the base or background color.
When applying the mottles or squiggles, don't allow the airbrush to rest on one spot. Keep your hand moving, working in small circles or squiggles and moving the airbrush in and out relative to the painted surface. Use a stand or box to hold the model in a comfortable position, and don't be afraid to use two hands on the airbrush to steady the hand that controls the trigger. Spraying mottled camouflage or fine lines is time consuming and tiring, and using two hands will help delay fatigue and cramp and avoid unfortunate accidents.
Lastly, don't obsess about your airbrush. Your skills and the practices you employ as the artist are much more critical than the tools you use
. While I wouldn't ever recommend that you buy a cheap airbrush, or one of those Chinese-made Iwata clones of indeterminate quality, very good results can be achieved with any reasonably good quality, mid-priced airbrush. I know a lot of people who slate Paasche's H for it's relative unsophistication and the fact that the parts sometimes appear to have been machined on 18th century equipment, but Sanford's FW-190 was painted with an "H", and others like Roy Sutherland and Mike Oehler have done some excellent work with this airbrush. Italian artist Alberto Ponno produces some INCREDIBLE miniature portraits using automotive acrylics shot through an "agricultural" Paasche V. I personally don't like Aztecs, but Brett Green and Chris Wauchop produce some simply amazing camouflage finishes with them. Iwatas, Harder & Steenbecks, Richpens, Tamiya's HG series - all are finely made precision instruments, but as much as I love Iwatas and Olympuses (Olympi?), I have to concede that there isn't much I can do with them that I cannot do just as well with my old Badger 200. Double-action 'brushes may be more convenient to use for mottled finishes, but these techniques apply equally to single-actions. Just remember the basics: keep your airbrush clean, use appropriate paint-thinner ratios, air pressure, and distances, and practice, practice, practice.
I'm sorry this is so long, but this is a subject that I have a great interest in, and that I've been collecting information about for a long time. I've tried just about everything at one time or another, and made a lot of mistakes along the way. Recently I've been teaching my eleven year old nephew how to spray mottled camouflage on one of his projects (and he's astonishingly good!), so these thoughts have been frequently in mind of late.