Airbrush not working - what am I doing wrong?

[Beardylong]

I'm hoping someone out there can help me!

I've come back to scale modelling after a 30+ year hiatus and am loving it! My first attempt was a 1/72 Airfix Mosquito (see my profile pic), which I brush painted. I started reading around the subject and learnt loads of techniques which I enjoyed trying out. Next stage was clearly to move to airbrushing so I searched the t'interweb and ended up buying a Badger 200nh single action suction feed airbrush. As I'd already forked out a load setting up my work bench I couldn't justify a compressor so I'm using canned air for the time being.

The problem is that I simply can't get any control out of the brush!

Instead of controllable fine lines, I get a random sequence of large wet splodges, nothing but air and then a very thin dusting of colour. I tried in vain to pre-shade the panel lines on my 1/72 Airfix Sabre (using gloss black, that someone had recommended in an article I read) and pretty much painted the whole model. Nothing like it looked like in the article with nice narrow lines over the panel lines. In a review of the 200nh, the reviewer sketched a little smiley face no wider than a scalpel. I must be doing something wrong!

I tried spraying while twiddling the needle adjusting screw and that didn't seem to make any real difference. Seemed to be simply on or off. Are you supposed to be able to vary the intensity of the air? I've ended up using a whole small tin of Badger air and half a big tin with no meaningful results. Is the tinned air the issue?

Perhaps it's the paint? I'm using Humbrol enamels thinned with Humbrol thinners. I've read the ratio of paint to thinners should be 50:50, to a milky consistency. But are we talking full fat or skimmed?! Or even gold top?! Dosing thinners is easy with a pipette, but I'm struggling to dose the paint. Any tips? Could it be that the mix is too thick? or thin? I'm using the glass jar with siphon pipe but perhaps a Badger metal cup would be easier?

I'm getting good at stripping down the brush & cleaning it and to a layman's eye, there's no apparent damage.

So I'm feeling pretty disillusioned at the mo - got a new toy but don't know how to play with it. Can anyone enlighten me?

Thanks in anticipation for a bit of inspiration

Beardylong (and the irony is I haven't got a beard any more!)

[chadders]

Unfortunately, to get the control your looking for will require a compressor. As a temporary solution I'd suggest turning the air down as low as it will go and make sure the paint is thinned to the correct consistency and make sure the needle is tightly seated. Then practice bringing the air/paint flows up till you get something close. I doubt you'll get super fine lines because a) the needle in the brush is too big and you have very little air control. With a compressor you should be able to get to about 1mm lines, but I think you'll struggle to get that fine with air cans

[little-cars]

It's easier to help face to face than with a few words on the net.

It looks like you are in Tring, if you would like to come along to the New City club in Milton Keynes next Monday, we can possibly point you in the right direction.

http://www.newcitysmc.co.uk/

Ta,

Paul

[Beardylong]

Thanks chadders and little-cars. I'm new to this forum malarkey and am really pleased that I'm getting responses only an hour after posting! Marvellous. I'll start working harder on the compressor justification ("if the forum says it, it must be true, dear"!) & will try to come along to MK in a few week's time. Any thoughts on getting the right mix/consistency of paint?

[fostersdave]

pop along to your local chemist and ask for an oral syringe,made of plastic,easy clean and marked with dosages on the side(there used for giving things like cough mixture to children)about 50p each..exact mixing ratio's

good luck

dave

[Beardylong]

Thanks Dave. Good idea. Syringes will be easier to clean than pipettes. We'll also keep the ones that come with the kid's Nurofen.

Any idea on the correct ratios for enamels?

BTW, may be able to win the compressor justification by offering to spray fake tan on the Chief Financial Controller's legs!!

Next question will be of course, which compressor to buy?!

[Greg B]

Most mixing I do by eye. Its not difficult and what comes out of the brush backs up your judgment. The paint should be the consistency of milk. Look at milk in a glass and tilt the glass slightly, how the milk runs back down the glass leaving a thin coating on the side of the glass is what you want to see if you do the same with your paint mix in the cup. Then its down to air pressure. Thicker the mixture, higher the pressure, thinner the mixture lower the pressure. And for really thin lines, you need a really thin mixture.

Air cans will not cut it. The pressure is too inconsistent as the can cools due to the evaporation of the propellant inside.

A single action brush is also very limiting for control, I'm trialling one for a review and compared to a double action brush, its like trying to walk with your laces tied together.

[little-cars]

If you come along next Monday we can go though all the options for compressors, paint mixing etc........

If you bring your kit along then we can have a play and see if we can get you sorted out.

Paul

[Will Vale]

I've sprayed a pre-shade with canned air, and while people are absolutely right that the pressure changes over time I still got 15 minutes or so of reasonable (half-centimeter) lines before the can got too cool and the pressure dropped off. That was with a gravity-fed brush and acrylics though.

I'd definitely investigate a bit further (with Paul!) before you get a compressor, although you're bound to want one in the end - air is expensive

Will

[Mike]

Most mixing I do by eye. Its not difficult and what comes out of the brush backs up your judgment. The paint should be the consistency of milk. Look at milk in a glass and tilt the glass slightly, how the milk runs back down the glass leaving a thin coating on the side of the glass is what you want to see if you do the same with your paint mix in the cup. Then its down to air pressure. Thicker the mixture, higher the pressure, thinner the mixture lower the pressure. And for really thin lines, you need a really thin mixture.

Air cans will not cut it. The pressure is too inconsistent as the can cools due to the evaporation of the propellant inside.

A single action brush is also very limiting for control, I'm trialling one for a review and compared to a double action brush, its like trying to walk with your laces tied together.

Quoted for truth. Air cans will rapidly burn a hole in your wallet too, as one won't last very long when you factor in cleaning your airbrush after a spray session. I think cans start off at 45psi (read that somewhere), and you really want around 15psi/1 bar for most jobs - I rarely move my compressor's regulator to anything else. The twiddly knob on top of the can can't give you that control with any reliability, and once you factor in cool-down as you use it, you're widdling in the wind

Bite the bullet, have the discussion with the long haired general, and make a step up - you'll not regret it

[John Laidlaw]

Following on the air can debate, they will only give you a taste (and for a very short time) of what what any airbrush can do. You need a constant, controllable source of dry, pressurised air - cans won't do this due to adiabatic cooling, and will cost you a small fortune into the bargain. In the long run, a compressor and a good regulator/moisture trap will actually save you money. A single-action brush will give you the control you need, but only if you're prepared to spend a great deal of time practicing with the setup. Double-action brushes will allow you to produce every effect you're after, but again, only with a great deal of practice.

In short, take Paul up on his offer of help, and you'll be well on the way.

Good luck!

[spitfire]

I am a Badger 200NH user and I generally only use enamel paints, mostly Xtracolor but I have used Humbrol paints as well, the first step is to ensure that the paint is fully mixed in the tinlet, I use a battery mixer and mix for at least 2 minutes so that the paint is nice and smooth. I measure out the paint and thinners using a pipette (they are as cheap as chips on e bay) normally I use a 50:50 mix, and I do the old jar test thoroughly mix the paint and thinner then tilt the glass jar and level it again the paint should roll (!) back and leave a thin colour film on the side of the jar. I use Xtracolor thinners no matter what paint I am using (Xtracolor, WEM Colourcoat,s MM or Humbrol)

I then set the air at 10-15 psi and using a sheet of A4 paper I draw a line while adjusting the paint flow at the end of the airbrush, depending on what I am painting defines how much paint that I put through the airbrush, then we are away, nice smooth movements, always keeping the airbrush moving.

Hope this helps

Cheers

Dennis

[Beardylong]

Thanks all. Glad it wasn't just my ineptitude! Will pop along to see Paul in a few weeks when I'm free.

[little-cars]

Just realised that the club meeting is next Monday the 12th, not today.

Paul

[roymattblack]

If you don't want to get a compressor yet, buy a car inner tube and pump it up with a foot pump.

Attach your air brush - away you go.

I did this for around 5 years before I bought a compressor.

It was never any trouble and cost nowt in terms of air....

Roy.