Airbrushing!!! "Everything you wanted to know but were afraid to ask"

[Nigel.D]

First of all lets clear up one thing!! An Airbrush will not improve your models, infact it will make them look worse! Only once you have got the basics right can an airbrush help you to improve! I suggest people view Bunkerbarges " Back to basics" before you even think about using an airbrush! That being said an Airbrush can make a model come to life. It can convey a sense of depth detail and finesse that no brush can compete with!

So lets examine what an airbrush is. As stated its not the be all and end all! Its a tool to help you acheive results that can be incredibly realistic or it can highlight every flaw on your model. An airbrush is simple its a brush that uses air to put paint on a surface !!!!! Im afraid though its not that straightforward.

A popular misconception is that an airbrush is an airbrush is an airbrush!! This is not so. Airbrushes come in two types "single action" and "double action" Cheaper alternatives are actually spray guns or atomisers! i will try to explain the difference.

An Atomiser or spraygun works by blowing air across a opening creating a vacume that lifts the paint up into the airflow producing a spray. See badger 350 paasche vlr humbrol and so on. Humbrol revell also sell a rebadged badger 200 which are single action airbrushes

Single action Airbrushes use a needle that is operated seperately from the trigger Ie a knurled screw that is at the back of the airbrush this arrangement allows the needle position to be determined by turning it in or out " in for a finer spray out for a broader coverage" Whilst the trigger controls the airflow. Whilst superb results can be obtained from this type of brush , it does not give you the finnesse and control that a double action can.

Double action ie devilbiss sprite, iawata , aztec, badger 150 etc, paasche vjr. Give you total control of both airflow and paint flow from the trigger. Pull the trigger back increases the paint flow ! Push the trigger down increases the airflow! This then gives you unlimited control of the pattern you want to use from 1/64 fine line to about 1/4 inch broad pattern.

I at this time own a Iawata A badger 200. A devilbiss 63, A paasche vjr. All have their pros and cons but despite the Iawata being twice the price of the Paasche this is my choice of use when it comes to fine detail work. What im trying to say is that an airbrush is very much an extension of you they are what you make of them and practice practice practice is the order of the day.

The next installment will deal with paint types, flow qualities, and propulsion.

 

[adzam]

thanks nige, that has answered some of my doubts as to the different types,

could you gives us rough ideas of which type you would use for different jobs ?

do different type of brushes react differently to different paints etc .

i hope i`m not jumping the gun

Adz..

 

[wonwinglo]

Keep it going Nigel,you really know your airbrushes for sure,looking forward to the next installment.

 

[Bunkerbarge]

I knew this was going to be interesting!

Nigel, much appreciated, I look forward to the rest.

 

[Bunkerbarge]

Nigel,

From what you are saying would it be fair advice to offer that modellers should get to grips with a single action unit before going to the obviously additional expense of a double action brush or can double action brushes be used in a single action manner from the start.

I can't even comprehend at the moment trying to control paint flow and air pressure at the same time. I spend all my time trying to ensure that the brush is at the correct angle and distance from the job!

 

[noobee captain]

Nigel,

can you also give us a breakdown of what equipment is required and rough price ranges for the beginner?

Thanks

 

[Nigel.D]

More

Trying to deal with some of the queries raised

Single or double ??? A good double action should have a adjuster nut , wheel or screw that can be used to make the brush perform as a single action design the adjuster will push the trigger back to the desired point and all you will have to control would be the airflow!

The main drawback on some single actions is that they come with a jar receptacle rather than a paint cup. This gets in the way when you want to do fine freehand work.

as regards mediums i always use enamels not because they are better its because thats what i understand best they are what im happy using and i know the characteristics of flow dry time and coverage!

The most important thing is airflow or a compressor!!!! Please please please dont skimp on this a good silent type i.e fridge type of unit will give you many years of service and will pay for itself many times over The most important aspect of it is that unlike the diaphram kind you wont get the domestic authorities complaining about the racket! Seriously though a cheap compressor will be a mistake if it hasnt got a resevior for the air the supply will pulse!! resulting in uneven lines (almost a dot every couple of mills) A moisture trap is also essential as compressed air is hot and this holds moisture which will spatter on your paint finish causing you much annoyance and expletives. A good moisture trap will also incorporate a pressure regulator which helps no end in being able to spray a variety of consistencies and finishes. Propellent bottles are way too expensive !! You will be using 2 or three per model the costs soon adds up! you can also get a co2 tank but this to me brings other inconvieniences such as refilling etc Hope this helps a bit

 

[Bunkerbarge]

Nigel,

I think the biggest problem with disposable bottles, which is why I would always advise against them, is the fact that as the gas evaporates the temperature of the remaining liquid falls. This is due to an overall reduction in energy of the contents as the higher energy molecules (the gas) are removed from the bottle.

Anyway the result is that as the gas is used and the temperature drops the rate of evaporation reduces and consequently the pressure of the saturated vapour drops. The big problem is therefore that the pressure of these things is not a constant and it throws out any carefull airbrushing operation completely.

A compressor is the only way to go, bearing in mind the considerations that you point out.

 

[wonwinglo]

I once had a huge lorry inner tube wedged between my two sheds,with an adaptor it provided convenient but somewhat bulky pressure for my older Humbrol Studio airbrush.

Those cannisters are not very successful and as you say kick out water all the time.

Question for Nigel ? can I fit a pressure gauge and water trap between my Diaphragm compressor and the airbrush ? I have got away with it up until now but would like to at least fit the water trap,do they make a simple one that fits in the line ? those lines are so narrow.

 

[Bunkerbarge]

Guys,

These people are suppliers of all things air brush and can help with most requirements.

www.graphicair.co.uk

and

www.widespreadsolutions.co.uk

(They're in Yorkshire as well so they must be OK!!)

 

[Nigel.D]

Barry yes you can you can get a pressure reg with a watertrap that fits the standard compressor thread (its also a standard badger size ) so that will make life easier! If you have a diaprham type the regulator will go most ways to reduce the pulsing effect just make sure you dont use more than 15 psi as the badger hose is way to thin really. it can come loose from the airbrush after a few uses

 

[Nigel.D]

Richard the VJR you won has the facility to be used as a single action though it is a fine detail brush so dont be surprised if you dont get wide coverage

 

[wonwinglo]

*** Thanks Nigel,very useful,I will look out for one.

Barry yes you can you can get a pressure reg with a watertrap that fits the standard compressor thread (its also a standard badger size ) so that will make life easier! If you have a diaprham type the regulator will go most ways to reduce the pulsing effect just make sure you dont use more than 15 psi as the badger hose is way to thin really. it can come loose from the airbrush after a few uses

 

[jankers]

Whilst I would in no way advise as well as Nigel, here are a few thoughts on my set-up.

I use the Paashe VLS and diaphram compressor that came with it. This is really noisey but is fitted with the regulator/trap and I normally use it in a box about 2x1x1 feet with pull down lid. I also use a "lazy susan" turntable to allow for easy maipulation of the small workpieces.

Let me say right away that all my experience is with single colour coverings, nothing like the weathering effects Nigel talks about.

The pulsing effect , even through the regulator, is still present but can be nullified by using an extention air-line, I use a 20 foot job.

The regulator, together with the double action brush, does allow for the spraying of very small pieces without blowing them away. I always attempt to fit 1/8in dowel as "locators" to these pieces and fit them into pre drilled holes in a baseboard used only for spraying. Pieces too small to take dowel are held down with a blob of plasticine though this is not always succesful, some are blown away no matter how careful I am, more practice needed there.

 

[Nigel.D]

Richard people generally put the propellant bottles into warm water to avoid this problem (it works up to a pont)

 

[Nigel.D]

Part Two Of The Airbrush Guide

Well we have discovered what an airbrush is and the types you can buy, now what can it do ????

First of all the question you should ask is what medium i need to spray?

The second question is what do i want to spray? Il assume this is models lol!

What are we spraying Acrylics,Enamels,ink Or cellulose! now that is a different kettle of fish!

What we need to look at first of all is paint thinning. For enamels acrylics the paint needs to be the consistency of milk this will allow you to spray a broad range of patterns from fine line to infill. Of course you can use a thicker mix with higher airpressure and a more open nozzle or a thinner mixture with less pressure and a more closed nozzle (gets simpler eh?) The thing is as you get more experienced you alter your mixes to accomodate the finish and the piece you are painting! For instance if you use too thick a mix with too much pressure the finish wil dry too quick or even dry before it hits the surface resulting in a coarse sandy texture on the surface this is bad!!! But if your painting a afv and you want a cast texture then this is good!!!! Too thin you will get paint runs or too much pressure, too close you will get spider legs.ut then again too thin is ok if you want a wash or tint. the secret is in the air pressure and paint flow. In other words practice experiment and be prepared to start again. Do not go out and buy a brush thinking it will give you a great finish !! it wont only you can do that with practice and perciverance. In the same thought if you buy a top of the range Iwata Micron be prepared for frustration It is an expensive bit of kit capable of producing lines a hairsbreadth thick, but totally impractical for painting a large scale model. Its like buying a 000 sable and trying to paint your model with that.(great for fine detail but sod all use for anything else). Once you are happy with a mix you are ready to start spraying. Before you approach your model try it out on a bit of paper first of all so you know you have the correct pressure and paint flow. Believe it or not i have a bit of wall next to my bench where much to the wifes displeasure i tune my brush. It is covered with squiggles and signatures where i get the pressure and flow right before i approach the model.(this is not a general recomendation though as it does cause extreme discomfort on occasions) Another important bit of advice is if you are about to spray your model, your brush is 2" from the surface , you press the trigger and pull slowly back to the point you set, and shock horror no paint flow!!!! DO NOT repeat DO NOT keep pulling the trigger back as if your lucky nothing will happen, if your not a huge wash of paint will erupt and ruin your day. If the paint doesnt flow its for three reasons

1 the paint is too thick

2 the air pressure is too low

3 your nozzle is blocked because of paint lumps or foreign bodies in the mix.

The only answer is to empty and clean out before restarting. Though you can minimise this by filtering your paint through the mesh on a pair of old tights. but make sure the mrs is not around before you liberate them.

Getting on to cellulose. this needs to be a really wet mix ie thinned really well as it is so volatile it has a tendancy to dry before it reaches the surface giving an orange peel effect to the finish, this can be countered by spraying thinners directly onto the surface to help even it out but it is not really recomended. Much better to use very thin coats and build up the colour gradually, this should be done using a really low pressure whilst keeping the brush moving all the time, and remembering to lift the finger from the air trigger before moving the brush away from the model.

Trying to tell people all this is probably very hit and miss! you see the important thing is to get used to your brush learn its limitations, its strengths, Is it happy spraying spraying ultra thin lines or lines perhaps a couple of mill wide will it be capable of large amounts of infill? Is the paint cup big enough not to have to refill it every 20 secs. Does it feel comfortable to hold. Does it make you want to paint??? All these points are something you may like to ponder, but in the end an experienced person with a cheap brush can produce work infinately beter than an inexperienced one with an expensive one.

 

[Bunkerbarge]

Nigel,

In my very basic trials with a brush the one thing that I find the biggest chore is the whole process of cleaning it out afterwards. Are there any short cuts or quick fixes to help with making this task any easier?

Also another worry I have is putting the brush down while I reposition the job and the paint starts to dry on the brush. Is this a realistic worry and if so should the job be thought out sufficiently well enough to ensure that the painting can be done as quickly as possible without interruptions?

Thanks for the guidance, I really enjoy your tutorial and the further questions it generates.

 

[BlazingPenguin]

I used my airbursh for years when making fishing lures and was very happy with the results, the paint was just straight enamels and polyurethane varnish.

I fancy giving acrylics a try but dread them 'solidifying' in the nozzle or something, with enamels I culd just do that 'cover the nozzle and blow back' routine'....but can I do that with enamels? Do they dry too quick? Am I just panicking for nothing?....Cheers

 

[Nigel.D]

Replys

Richard!

First you can buy a can of "spray away" or sometimes called liquid reamer" this you just spray into the paint cup and nozzle and blow it through dead easy and i use it all the time. (this only applies to enamels though) As for putting the brush down I have made a simple holder from an old coat hanger that supports the brush stopping the contents from spilling out (dead easy and about 10p cost) basically its just a hook with 2 prongs screwed to the wall! As to paint drying in the brush if you just blow through air with no paintflow you shouldnt have that problem.

Pingu lol!

Yes you are panicking acrylics do tend to dry quicker in some cases but you would have to leave the brush for a good hour for this to be a problem! I personnaly dont like acrylics I find the finish and coverage when painting plastic models to be a lot less durable or even a lot less opaque. This to me means more paint and more effort to achieve a result also the curing time is far longer when you need to remask. some people swear by them but i have not found them (for my purposes) to offer any benefit at all.

If you worry about clogged nozzles or airways a 10 minute soak in cellulose thinners wil cure all just make sure you blow some spray away or a mixture of thinners and very light machine oil through to keep the packing glands from breaking or drying up.

 

[Nigel.D]

For the third part

I was thinking along the lines of some video ?? what i need from you guys is the type of airbrush work you would like to see??