Airbrush Needle size

[lightmaster]

I have just bought myself a Airbrush kit to spray my models,can anybody tell me what size needle I should use and air pressure when spraying the model?

Thanks

[David Jones1707820337]

 There is no "right" size or pressure (I presume you have a compressor with a pressure gauge)

I use a few cheap double action brushes off e(vil)Bay and have a 0.5mm for wide areas, a 0.35 for general and a (good quality) 0.2mm Badger airbrush for fine lines and detail, but with a bit of control you can get fine from a broad needle.

Pressure - I generally use around 15-20 psi, with well thinned paints, but again that depends on what you are spraying and the results you want.

Best suggestion is to practice on some old models (or plasticard) to find what works for you

[DavidJC]

Can we ask what airbrush you have bought? I don't know enough about them but I was under the impression that - generally - needles, though removable, are airbrush specific? That said, I think I have seen some airbrushes that have needles that can be swapped.  It seems that for general use a .3mm is fairly standard for close work and fine lines but also being able to spray a larger area. A .2mm needle is used for much closer work and much finer lines with larger areas being more difficult. Anything over .3mm is for much wider coverage, I believe, which makes fine lines more difficult as you go up in size - although I take on board Ossian's post above.

 

Do you have a compressor, or are you using the cans of air? Cans are great for a quick pass on a larger area or a quick and simple job, but you really are better off buying an air compressor with a pressure adjusting knob, even if it's relatively cheap and cheerul. It will save you loads in the long run and will give you far more control than a can ever will (which loses pressure very rapidly, even when new, when using it for more than a few moments at a time. Due to the propellant and contents, It 'ices' over, then you then have to stop to let it warm up before you can use it again).

 

Any airbrush though is a case of practice practice practice, and then practice again. Everything is a combination of air pressure and paint consistency and each will have a direct result on the other. I wish there was a simple formula or guide to achieve the best results but there is none. The amount of mess and even models I messed up in my early days of airbrushing is terrifying; even now I get things wrong although thankfully have learned alot and have now minimised those failures. I have also learned how to remove paint, particulary when still 'wet' to have another go, although that's not ideal.

 

As Ossian suggests try on some scrap plastic and/or old models before committing yourself to your newest model that you have laboured over. If you can afford to, build some cheap kits and practice on those first.

[lightmaster]

The Airbrush I have purchased is a Harder & Steenback Ultra 2 in 1 Airbrush with (0.2 & 0.4 Nozzles),also a Mini Piston Compresser.

[DavidJC]

Oh, very nice! They are excellent airbrushes.

 

So yeah, the .2mm will be for close work and beautifully fine lines, the .4mm will be for wider areas. Either way it is a case of practice practice practice with different pressures and different paints and their thinning ratios for any given circumstance.

[Ratch]

 The best advise I was given was to have the pressure as low as possible - just a puff, provided it works.

I turn the gauge right down and notch it up until the paint sprays well - the pressure may vary depending upon the viscosity of the paint.

[goofykurt]

 I was thinking about setting up three airbrushes. 1 with a 0.2 needle 1 with a 0.3 needle and 1 with a 0.5 needle. I am trying to use the airbrush to prime miniatures used in tabletop gaming in a fantasy setting.would there be an advantage in doing this? what would the 0.2 needle be used for? what would the 0.5 needle be used for? currently i am using the 0.3 needle. i am relatively new to airbrushing.

[peebeep]

Nozzle diameter is usually associated with spray pattern and whilst this is true up to a point, the idea is to match nozzle size to the pigment you're using. Airbrushes were originally designed for spraying inks that have very finely ground pigment, so a small diameter nozzle is what you would have used. Enamels and acrylics generally have larger pigment particles, so larger nozzles might be required, although more recently the model paint manufacturers are using pigments that are more finely ground. It's a case of experimenting to find out what works best for you. In respect of priming miniatures, airbrushing using a suitable media should give you a nice smooth base to work on and it's much more controllable than using aerosols. 

[Peter s]

Its largely dependent on how clean the brush is, how appropriately thinned the paint is, whether you want a heavy "base" coat or you're doing some subtle late war german blotch pattern etc. For most work I used a £10 chinese double action with a needle 0.2, 0.25 or 0.3mm. Pressure about 20psi but if the brush needs a good clean and I'm just spraying a primer coat all over I've gone up to 50psi. As Paul Brown says some paints aren't exactly ideal for airbrushing and if they start to clog the nozzle it can be a real pain. Its one reason I avoid using really expensive super-fine airbrushes. If they clog and spit its totally counter productive.

[Padefc]

Some brilliant advice above all spot on i use a harder steenbeck evolution .02 this works brilliant with vallejo air paint straight from the bottle in the main I use vallejo gloss an satin varnishes both require approx 50/50 dilution to use the h/s 02.I also have 2 cheaper version airbrushes as Peter said these will work almost as good as any perhaps a little less control than a h/s these are 03&03.5 needles I use these for Non vallejo paint and vallejo varnishes as they will spray it to a thicker consitancey meaning less diluting required.

I find humbrol Revell paint acrylics are very unpredictable in spraying even with a syrenge for measureing out for dilution some I find require far more diluting than others to achieve a nice spray pattern,I have some great results with these for eg in the pandemic thread I painted a 1/72 tomahawk with some humbrol an a cheap airbrushes. Trial an error are in reality the best way of learning am still a novice at airbrushing and every time I use one it's a school day.