I used to do a lot of plastic/resin kit modelling, which involved a lot of fairly precise airbrushing - if you're looking to do small-decoration airbrushing, I'd suggest a few things:
- While Iwata do make nice aurbrushes, they also make very expensive airbrushes. If you're not sure whether it's something for you, I'd still advise buying something cheap and generic
like this to play around with airbrushing before you drop a lot of money on expensive kit. Unfortunately I can't vouch entirely precisely for that one since I've not bought from that particular seller, but I own a generic brush which looks identical to that and comes in exactly the same case, and for the money it's nothing short of superb. The one I have is definitely a good beginner brush... just don't get put off if you do find it has manufacturing defects; send it back and don't automatically assume it's your technique at fault. Don't expect to be able to achieve neat, consistent 2mm spray-lines with a cheap 'brush like that, but from the ones I've seen they're usually fine for general use.
- It's definitely worth having a dual-action 'brush if you're going to do anything other than laying down flat colour. You get a much larger degree of control, can feather between two colours more easily, etc. I also find it easier to clean dual-action brushes for the simple reason that you can run the air without letting paint through the nozzle in between sprays, so there's not so much build-up to clean out later.
- Gravity-feed is much easier to use than siphon-feed (the ones with the bottle under the body of the airbrush), in my experience. It's less fussy about the consistency of the paint, and while you can accidentally spill paint out the top if you tilt it too much, I tend to find that siphon-feeds splutter more easily. The advantage for siphon-feed is that you can keep a
lot more paint in the bottle, so you can spray much larger areas without having to refill. I think my main gravity-feed brush has a 2ml well, but it's not uncommon to have 50ml bottles for siphon-feed 'brushes.
- You need a moisture trap on your compressor if you're working in a vaguely-humid environment, as otherwise the moisture from the air will gather in the compressor and tube and periodically droplets will come up the airpipe, come out at the same time as the paint and ruin your finish.
- It obviously depends on what you're airbrushing, but I found Tamiya model paints excellent to paint with an airbrush; thin them with isopropyl alcohol (available from a proper chemist/pharmacy; I get mine from Lloyds) to the consistency of milk and remember the adage that many thin coats is always better! You can re-use a lot of the technique of spray-painting from an aerosol can. (If you do use Tamiya paints, though, be aware that they're very fragile and absolutely require a varnish layer over the top. This goes for most airbrushed acrylic paint, mind.)
- Don't ever buy an external-mix brush ever. They're all, without exception, rubbish for fine work. These are the ones which are usually plastic-bodied, sold for £10 with a little can of compressed air on a cardboard backing as "starter hobby airbrush" and so on. I have no idea what they're good for, but it's not painting things. I'd also tend to advise people steer clear of Aztek 'brushes (with their weird miniature resin/plastic needle cartridges) but some people love 'em.
- Check the diameter and thread of the fittings on your compressor and be prepared to buy extra adaptors; they're usually pretty cheap if you know what you need. Unfortunately pretty much every major airbrush manufacturer has a different standard for hose fittings.
- I know you said you have a compressor already, but for the benefit of anyone else reading this thread: aerosol compressed air is fine for starting out, but it quickly becomes a very expensive way to run an airbrush... and has its own problems. Keep aware of how cold the can is while you're working, because every time you spray the can cools a bit (the liquid air inside is evaporating out into gas!) and once it cools too much you sometimes get bits of liquid air/propellant come out. Which obviously isn't good for whatever you're painting, and can burn skin if you carelessly spray onto the back of your hand to see if the 'brush is still working. Which I still have a faint scar from doing as a teenager!