Airbrushing 101

Here’s something I originally posted on the Hammertime 40K site but it will be more useful here, really…

Since I’ve gotten into airbrushing, I figured it would be a good thing to put all my collected info here. I don’t claim to be a total expert, but I’ve done an Introduction to Airbrushing DVD, I’ll be doing an airbrushing class for wargamers later this year, and I’m doing airbrush reviews and how-to’s for print and online magazines, so hopefully I’ve figured out a few things there and there, and to help out people just getting into airbrushing, here’s all the info I’ve put online. It’ll be regularly updated and at the bottom there’s a few videos demonstrating some of the really cool techniques you can get with an airbrush.

Why should I consider an airbrush? Have you ever felt so strongly about something that anyone you tell thinks you’re a crazy person, and when someone is telling you how they like to do something you can’t help but blurt out “no, that’s ridiculous, LET ME SHOW YOU HOW YOU SHOULD DO IT”? Well that’s kind of how everyone who uses an airbrush regularly feels about their airbrush. It’s hard to sound not-crazy about something that is so awesome, and it’s impossible to not sound like an evangelist about something that is so helpful and great.

OK, great, whatever, so what can I do with an airbrush? 
How about all this:

  • priming (big deal!) indoors! (ok, wow)
  • basecoating
  • color blending
  • those sweet power swords that people love posting
  • preshading – putting a shadow under the base coat for instant shading
  • OSL (Object-Source Lighting) is easy-peasy and very quick
  • fast varnishing
  • changing colors is as easy and quick as with a brush
  • EASY speed painting, if you want
  • fast painting of vehicles with NO brushstrokes!
  • use minimal paint
  • shoot very thin coats (see ‘use minimal paint’, above)
  • paint from an airbrush dries very quickly (see ‘shoot very thing coats’, above)
  • (are you getting the idea yet that airbrushing really helps to be a quicker painter?)

When should I consider an airbrush for my models? I think the breaking point to really think about one is when you don’t want to (or can’t) prime and varnish outside, if you start to have a lot of models to paint, and especially if you want to get into painting static models or wargaming vehicles or scenery.

Alright, so any drawbacks? Well, to be honest the main drawback is cost. However, if you’re happy to start with bargain-basement stuff you can get going for under $50/£40 easily, which is the cost of one good-sized wargaming model these days. Of course you can spend a lot on an airbrush, all the equipment and a quiet compressor, but you don’t *have* to when you’re starting out. After cost, the next drawback is making the time to learn how to use your equipment (just like any tool) and having the patience to figure things out.

So what are the start-up costs? If you’re not worried about starting with brand name stuff from the start, check this out (£80, UK) or one of these ($40+, US) – these aren’t affiliate links. These are generic compressors bundled with one or two cheap (and I do mean CHEAP) airbrushes. You don’t need to get any special thinners or airbrush-ready paints (the paints just help speed up your painting), of course you can use the paints you already have and plain water to thin them. Use an old brush to mix the colors in the color cup, and paper towels plus ammonia-based window cleaner for cleaning. If you don’t want to get paint on your fingers (I don’t like to), get a box of unpowdered nitrile gloves, a DIY store will have 100 for a few bucks/pounds. You’ll want to get a cleaning station (basically a jar you can spray thinner through the airbrush, and the jar collects the thinner/water) but you can make one or buy a cheap one for £10/$10. These usually include a stand for a single airbrush, also, saving you the £15/$15+ for a separate stand. An airbrush setup could cost you under £100/$100 if you shop around, so it’s a great thing to maybe ask for Christmas or as a birthday gift.

What about the noise? Space and noise can be a big issue, but my compressor is barely loud enough to hear on the floor below. My old ‘shop’ compressor is super loud and I could hear it 2 floors below! In fact, I’ve often forgotten about it after finishing up and even though my bedroom is under my model workspace, I’ve slept right through it coming on during the night (because of a tiny air leak somewhere in my connections the compressor will want to refill itself every 15 minutes or so if it’s not switched off). So it’s not loud and doesn’t take up much space – especially for an ‘essential’ hobby item (think about how much space your figure cases take up, for example).

I don’t have much space, what about that? As for space, a compressor is probably about the size of 2 or 3 shoe boxes (stacked one on top of another) once the cord is wrapped up, and the airbrushes themselves take up the space of a few writing pens (so not much room at all). If you get really busy with airbrushing stuff you’ll want to get a spray booth, assuming you can’t simply use a fan and open window to direct any airborne paint particles outside. A spray booth simply uses a fan to suck paint particles away from you (so you don’t breathe them in) and into a filter or a hose (like a dryer vent hose) that leads to a window.

Is there a video I can watch that has everything in it a wargaming painter should know? Yes! If you have an hour to kill, watch/listen to the video below from the owner of Badger, Ken. It was filmed at a wargaming convention and is a seminar he does (yes, to promote Badger airbrushes, so what, they’re great) and is specifically geared towards wargaming painters. It covers just about every that is in the outline below the video, and in fact much of it formed the basis of the outline info.

The outline below is what I wrote up to cover all the basics for the airbrushing basics DVD I did. It covers the basic way airbrushes work, how to choose your first airbrush, how to set up your painting area and with what equipment, plus how to clean your airbrush and do some basic troubleshooting. I’ve rewritten where I can so it’s more suitable for reading. I know pictures would help a lot, and I’ll add them when I can.

AIRBRUSH DETAILS
How an airbrush works 
1. where paint goes inside the brush: into the inner chamber where the needle rests
2. where air goes inside the brush: into the outer chamber which surrounds the paint & needle chamber
3. press trigger for air – push further down for more air (up to the pressure you’ve set from the compressor)
4. releasing paint
i. single action brushes have no forward/backward motion on trigger, so simply press down and air is released and the air pressure pulls paint from the inner chamber, mixing with the air and paint is sprayed out of front of brush. You can adjust the needle manually (e.g., not with the trigger but with a dial control on the back of the brush) to decide how much paint comes out
ii. double action brushes control air pressure and the needle, so as you pull trigger back AND press down on trigger the needle is pulled back and air flows from outer chamber, mixing with the air and paint is sprayed out of front of brush

Mix
1. internal mix – air and color mix and atomize inside to spray out, finer dot pattern (‘hi-res’), good for large surfaces and tiny detail
2. external mix – mixes outside the body of the brush, larger dot pattern (‘low-res’), no good for detail work, bottom feed only, only good for large surfaces like automotive work

Action
1. single action – easier to learn, generally cheaper, fine for applying single color to relatively large surfaces, basically a very finely tuned spray can, limited to basic techniques
2. dual or double action – can control paint flow, can do all basic techniques, gradiations of color density, line varying while spraying

Feed
1. gravity feed – ideal for detail work, wargaming, scale models
i. advantages: best for detail work, lower pressure required, gravity does the work, paint goes furthest with gravity feed, less parts, easier to clean, quicker color changes, uses a very small amount of paint
ii. disadvantages: paint cup limits size of color available, some models have interchangeable paint cups
2. siphon/bottom feed – for spraying large amounts of color, fabric, canvas work
i. advantages: general-purpose airbrush, best for spraying large surfaces or amounts of paint, can purchase muliple paint jar caps to fit paint bottles direct to brush
ii. disadvantages: higher pressure requires faster spraying and passing, less control, uses more paint, more to clean
3. side feed – used to be mainly for photo retouching because it doesn’t block view, now used mostly for car detail work – uses a cup or jar attached to side of body
i. has some advantages and disadvantages of both gravity and siphon feed

AIR SOURCES
Canned air – cheap initially, variable pressure as you use it, don’t consider! £8/$8+
CO2 or storage tank – silent, can last a long time, but high initial cost plus need to refill, £50/$70+?
Compressor – diaphragm type is loud, piston is quiet, look for model w/ at least 30 psi, £30/$30+
‘shop’ compressors – may require oil, loud, may require long hose and adapters, £100/$75+
Compressor with tank – best option if painting often, the tank saves wear on motor, some users claim no ‘pulsing’, £80/$100+
You must get one with a tank to stop the pulsing’ – this is a myth, see the video above
Your best air source depends on how often you’ll be using your airbrush – 1-2x a month, get cheap compressor; 1-2x a week, get a brand name with a tank

HOSES & REGULATORS
hoses 
1. avoid vinyl hose – kinks very easily
2. coiled hose – keeps out of the way
3. clear hose – with barbed or clamp connectors
4. braided hose – most durable, most recommended
5. Iwata connector to fit Badger models (some Badger brushes come with the adapter – check the specs before you buy)
6. use plumber’s Teflon tape to secure threaded fittings
7. quick-disconnects speed up brush changes if you have 2 or more brushes
moisture trap
1. Why? compressor will become warm and push out warm air, which has water vapor in it – when the air cools as it moves away from the compressor, the moisture becomes liquid. The trap holds the moist air and liquid, and keeps it from going down the hose to your brush
2. Get one with a gauge (most have a gauge and regulator) – if doing static model work, get one with marks every 2 psi rather than every 5-10 psi
3. if compressor is equipped with a tank, the tank acts as a moisture trap (but *must* be drained every 1-2 months to prevent rust)
4. best location for the moisture trap is 18”+ away to let air cool, but nearly all compressors have a moisture trap fitted with very a short hose length (usually right on the compressor, which is not ideal but better than nothing)
5. in-line moisture traps are available for braided hoses (must sit vertically)
6. multiple traps are good for humid or damp areas (Florida, Britain, etc.)
regulator
1. ideally, use regulator on moisture trap for air pressure – most compressors come with a regulator fitted

VENTILATION
Minimum: good airflow, large room (or outside if possible) & dust mask
Best: open window, strong fan & activated carbon filter mask (half-face painter’s mask from 3M or similar)
remember that pets & children won’t be wearing masks, so keep them out of the area while you are painting

WORKSPACE SETUP

  • compressor setup & hose routing – depends on noise from compressor: if it’s loud, use a long hose and keep the compressor in a different room or closet to contain the noise
  • airbrush holder – ideal for when you have an airbrush with paint in it, most cleaning jars have a built-in holder
  • cleaning supplies – water, airbrush thinner for acrylics, mineral spirit for enamels, cleaner jar, bottle, kitchen towel, cotton tips
  • accessories – pipettes/droppers or straws, brushes, mixing cups, different size siphon jars, siphon jar filters, inline moisture traps, multiple hose connectors, QD connectors and hoses
  • spray surface – paper, cardboard or scrap material for testing…plastic drink bottles work great for our purposes, since we’re most likely painting plastic models, and the bottles are free!
  • tape – generic tape, modeling tape (Tamiya brand), teflon tape for connections
  • safety – respirator, spray booth/fan, open window, nitrile gloves if holding parts
  • old drink bottle or food container with lid – to dump paint into
  • clean water jar and thinner
  • consider your working temperature – colder: spray farther back; warmer: spray closer so paint doesn’t dry before hitting surface

CHOOSING AN AIRBRUSH
now that you know about the extra equipment you will need, the first thing you need to know is there is NO one ‘right choice’
needle size choice – get appropriate size for your needs, make sure to get correct nozzle/needle head
quality – brand names & make – you generally get what you pay for (like with anything)
don’t get attached to one brand or model…but consider sticking to one brand because of shared spare parts
spares – make sure you can get replacement or optional needles, tips, heads, cups, etc.
‘best choice’ is one for large surfaces, plus one for detail
if only one brush is possible…then get the best your budget can afford – remember to get what fits the application you will be using it for
try one out to paint if possible, or at least hold one if you can (a friend’s brush, or in a shop)
consider future needs & what you might be doing in the future – buy for the future with advanced features if needed
Budget guidelines
i. up to £20/$30: copies of popular models, quality can vary widely
ii. up to £50/$75: best choices are probably mid-budget Badger like the Patriot or the Neo from iwata – these have brand name support and good warranties
iii. up to £100/$120: brand name (Badger, Iwata, Harder-Steenbeck, Thayer & Chandler, Grex), top quality budget models w/ good warranties, Teflon coating, etc.
iv. £150+/$175+: professional-quality, designed for daily use all day, more rugged and more features
v. extra cost buys you better reliability, smoother action, factory warranties, easy spare parts availability and better consistency with the airbrush
if you’re just starting out, get a cheap model or borrow airbrushes and see what you like and don’t like
the ‘best’ airbrush is the one that fits the job you have at hand, that you find works reliably

PAINT
Stirring or blending is best to keep pigment suspended in paint medium for consistent paint each time
Thinning
i. how thin – start with consistency of skim milk and thin/thicken as necessary*
ii. what to thin with – same-brand thinner or water (if acrylic) – distilled water if storing
Acrylics – non-toxic (paint dust is still bad for your lungs, mmmkay?), water clean-up and thinning, can be more susceptible to tip dry
Enamels, lacquers, urethanes, etc. – requires thinner, airbrush must have thinner-safe parts (Teflon-coated parts, no rubber, etc. – name brand airbrushes are used in automotive painting so are generally safe exposed to lacquers and thinners), easy to clean with thinner
Where to mix – jar if bottom-feed, small mixing cup if gravity-feed
*skim milk is just the starting point – your mileage WILL vary depending on brand of paint, needle size, air pressure and more, so you will have to experiment and keep mental (or written!) notes about how much to thin various paints for what you’re doing. Your paint when spraying OSL at below 10psi, 2 inches away from the model, will be much thinner than when you’re laying a base coat at 30psi, 12 inches away.

BASIC TECHNIQUES – practice on cardboard or old models
some beginner techniques to get you used to your airbrush
1. base coating large area
2. dots – various sizes
3. squares – connect the dots with short straight lines
4. lines – longer lines to get used to spraying long lines
5. dagger-strokes (thick-to-thin lines, thin-to-thick lines)
6. circular or curved lines – draw curved lines on paper and try to follow the line (as if it were a panel line on a vehicle)
7. circular dagger-strokes – more advanced, lots of movement!
8. gradients and fades – can be harder than you think, practice fading one color into another
9. practice, practice, practice!
Base coating – priming, large areas
1. 25-35 psi depending on type of airbrush and thickness of paint
Detail work – finer tips, thinner lines
1. lower psi, 15-20 or even lower (even 4 psi) depending on airbrush, paint and width of line desired
2. start with your normal psi for base coating and use a practice model if you have one
3. see how close you can get to the model before the paint starts to spider – experiment with lower psi, or thinner paint with more coats to get the effect you want
4. as always, practice (and experimentation) makes perfect
Specialty work
1. masking
i. tape – use Tamiya masking tape for sharp edges (use cheap tape to cover larger areas) – varnish the area first to avoid the tape lifting up tape
ii. Blu Tac/Silly Putty for fuzzy/varied edges
2. stencils
i. can buy pre-made flame, demon or whatever stencils
ii. can buy packs of Mylar film to make your own stencils (flame templates are easy to make)
3. freehand – takes practice! but a great technique to master
8. pre-shading – black into panels or shaded areas before base color
Protecting – varnishes
Future Floor Wax (US) or Kleer/Pledge (UK) is cheap, super-durable (both are clear acrylic gloss medium meant to provide shine for floors) can be shot straight through the brush – let dry after spraying and put another coat on before using oil wash or applying matte varnish

CLEANING
color changes and basic cleaning
1. dump or spray out old color
2. rinse cup with cleaner & paper towel
3. spray out 2-3 drops of cleaner 2-3 times
4. spray a few ml cleaner into cleaning station
5. siphon feed – keep a bottle with fresh/clean cleaner/thinner for spraying out
backflushing useful when you haven’t cleaned properly in a while
1. for bottom feed, the cleaner bottle used for backflushing is the backflushing bottle from now on
2. for gravity feed, a few drops of cleaner in top is all that is needed, then dump out
3. then use the same basic cleaning steps
‘end of painting session’ cleaning – also see this video
1. flush out with cleaner
2. remove needle carefully and clean (carefully)
3. wipe out paint cup/siphon tube completely
4. clean up outer body and reassemble
if trigger is getting ‘gunky’ – if not cleaning properly, or maybe after several days or a couple of weeks
1. first do basic cleaning steps
2. follow manufacturer’s cleaning suggestions – do not disassemble if they recommend not to!
3. remove needle and nozzle assembly: paint tip & spray regulator – the only parts that come in contact with paint
4. put small parts in thinner, isopropyl alcohol, ultrasonic cleaner or glass with fizzing denture cleaner, let soak for an hour or two
5. inspect needle, use cloth with cleaner to take paint off or fine steel wool – be careful to work with needle between fingers
6. cleaning kits and brushes are not necessary
7. reassemble
8. if paint is inside the body of airbrush it will probably need factory inspection
9. brushes and pipe cleaners sometimes not recommended by manufacturers because they can scratch the inside, causing problems, but they can be useful for cleaning siphon tubes, etc.
d. explain again that complete disassembly is almost never needed

PROBLEM SOLVING
Just like any tool, there are a variety of ‘problems’ that can come up in regular use. Below you’ll find the most common problems and a variety of solutions to try to solve the problem. With experience you’ll find out what to do to prevent each problem, but for now here’s where to get started. 
Spidering 
– spraying too close, paint too thin, trigger open too much and/or pressure too high
fix: spray from farther away, check air pressure, don’t pull trigger back as far
Tip Dry – most common with acrylic paints, this is when paint starts to spray off-center because of tiny bit of paint on tip of needle – ‘tip dry’
fix: clean and lubricate needle using needle lubricant, don’t take breaks without cleaning the airbrush properly, often confused with clogging, replace needle if bent
Tip dry will happen much more often with acrylic paints, especially when spraying slightly thicker paint or at higher psi (20+ psi)
Bubbles in cup – most common cause is head or tip clog, air is not flowing normally and forced into paint cup
fix: clean tip, thin paint properly, watch needle during painting for paint build-up
gritty paint – spraying too far away, paint is drying before contact with surface
runny paint – move the brush smoothly using passes, spray from further back
paint coming out with trigger at ‘zero’ (without pulling the trigger back)
fix: re-seat needle into tip
spatters occasionally while painting – water in air hose
fix: get a moisture trap installed, move trap 18-24 inches from compressor, add another moisture trap on braided hose
spatter at start of paint – needle left on tip after last pass
fix: spray onto glove or scrap material
check air pressure regularly after first setting up, could find leaks

Quick and dirty info on CHEAP BADGER SOTAR AIRBRUSHES – why so cheap, when airbrush suppliers can list this at $400+? Badger don’t use a ‘minimum advertised price’ policy, so sellers put the price at whatever they want. Some sell it high prices, but Amazon bought a huge quantity and have been flogging them for $75 or so for several months now and goons have been jumping on the bandwagon. It’s “a lot of airbrush” for babby’s first airbrush, but it’s a GREAT airbrush. The only thing it might not do as well as other airbrushes is large area coverage (think very large terrain pieces), but other than that it’s a great airbrush, especially at $75.Details on the Sotar: it has the same internals as the Renegade (which is a great brush also), it just has a different shape to the outer body because it was designed for illustrators used to technical pens, and the Renegade series were designed for scale model builders used to thicker brush handles.

Here’s a selection of videos showing how some of the most popular miniatures painters online use their airbrushes

Preshading vehicles (also shows pinwashing starting at 2:00 and pigment use starting at 3:05)


You can skip the highlighting step and still get a great-looking vehicle with just a wash and some drybrushing

Painting large areas of flesh

Color changes, painting large amounts of one color, and cleaning

Daily airbrush care (cleaning it after you’re done for the day/night)

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