I see a lot of compressor questions. I’ve used airbrushes from the little hand held hobby ones to a full size one used to paint cars. I’m hoping this information will help a bit. I’m not going to talk about what you need to paint cars – just fine scale models at this point.
See the photo below. That is a US$70 compressor. That might sound like a lot but that is the minimum I would tell anyone to start with. Cheaper ones will very quickly frustrate you. Here is what this has over most of the cheaper ones.
1) this unit can go up to something like 50PSI (4.4 bars differential to atmosphere?) You will need a high psi at time for paint that you cannot always thin way down or for when certain effects need to be done at a longer distance. You will learn how to adjust pressure as needed. This regulator also has a lock – you pull up to adjust and pull down to lock. The last thing you want is for the pressure to be changed accidentally. This is a nice wide range regulator from < 1 psi to something like 100. All metal parts inside.
2) this unit has a moisture trap. You will not believe how frustrating it can be to get a varying amount of moisture on your model as you paint. Your surfaces will never be consistent from day to day and season to season.
3) unit has a gauge so you can actually tell what PSI and take note of what is best for your situation. These gauges are often not perfectly consistent from unit to unit so your exact measurement may not work for others – but you will learn your unit and it'll be close. Anything with adjustable regulation but which does not have a gauge is useless. You will have to start low and work up or vice versa until you are getting a consistent spray -since you are spraying 'in the dark' you will waste a LOT of time and paint trying to get something to work.
4) This one has a TWO YEAR warranty – so it's made to last. Gets really hot if you are spraying a really high PSI for a long time – so it has a thermal shutoff for protection. For my use I don't think it's really even warm to the touch. Show me any of the 'hobby' grade stuff that is built like that. I've been using mine for over 10 years now at least 5 hours a month (so like 600 hours on mine) without a hitch and if it went out today I would get another immediately.
5) actual metal fittings that take standard spray accessories – I can add longer hoses (which you will like) and use multiple brushes with a splitter (maybe I"m rapidly changing back and forth between two colours). Sometimes you may need to buy adaptor but they are easily found in the US.
6) this one has a reservoir – it's not trying to just make a constant supply – anything without a reservoir will surge a lot and again not make a consistent surface – and if not a consistent surface, may as well brush paint. Along with the regulator you have now decoupled the compression and painting sides. This also allows the compressor to start/stop and produce less heat. It's disconcerting at first to have it start/stop but you get used to it – and pretty much every compressor set up for painting small and large has a reservoir and start/stop.
Finally, something not part of this unit – PROTECT YOUR LUNGS/EYES. Do not spray without a vapor mask – even outdoors you can get blow back. A vapor mask is not one of those thin paper things. I've attached one below. A lung or eye full of enamel paint and thinner will be VERY harmful. It's not a joke. Even spraying water based paints the pigment is bad inside your body. It needs to be organic filtering – this one is like $20 US. And remember please – you do not want your family breathing even low levels of thinners – you really need to exhaust to the outside.
So, I know this does not help people that already have a compressor. I can say that if you are getting into airbrushing – please get something like this to start or you will struggle to get the results that you want.
I also know this idea is probably not helpful – but if your compressor setup does not have these features – honestly – trash it and get something like this. A typical compressor and dual action air brush at online US prices cost LESS than many Gunpla MG Ver Ka kits.
If anyone wants something like this about dual action brushes please let me know…. I've always got at least 2 opinions on everything and sometimes they are even consistent.
Don't mean to denigrate anyone's setup and this is just my input so please take it for what its worth. And for international audiences I apologize if this comes off as american-centric I just don't know the availability of these things outside the US.