Air brush

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Kittyhawk

Established Member
Joined
30 Apr 2021
Messages
562
Reaction score
1,164
Location
New Zealand
There have been a few posts from me over the last weeks expressing a little dissatisfaction with the quality of the teak oil finish I was getting on the model aeroplanes.
So finally got an airbrush setup which I probably should have bought in the first instance, but have one now because the grandson is at uni and got himself a part-time job at a hardware store and as staff he gets a 60% discout on it so too good to pass up.
I have a little spraypainting experience but have not used an airbrush before.
So how do you determine the right paint viscosity for an airbrush? With my conventional spray gun I used a Ford Cup but don't think this would work for an airbrush.
I plan on using ordinary turps based paints and clear finishes but see that some of the more exotic coatings have a brush thinner and a different spray thinner - can ordinary enamel paint and varnish which are thinned with turps use turps for spraying?
With an airbrush can I spray wet on wet with just a tack off between coats? Coating the aeroplanes in a day instead of a week would be very nice.
Any advise/help much appreciated.
 
I use an airbrush quite a lot in my workshop for one item that we manufacture, I have never tried to spray oil but have had some interesting results spraying paint and in particular none air brush paint!
Airbrush paint is fairly expensive however it does go along way, we first ran into problems when a customer wanted their items sprayed in the colour of some woodwork in their house which was a mainstream paint manufacture colour satin wood finish, we thinned it down to airbrush consistency (skimmed milk) and done some test sprays, what a disaster
Much research then took place YouTube, Google, Forums, visiting a local airbrush artist, The learnings are that you cant put everything through an airbrush due to the needle size and the size of the particles in the paint, even upping the needle size of an airbrush to the max available still didn't produce acceptable results, further research found that airbrush paints are made with much finer particles for colour and metallic than non airbrush paints.
I'm not sure how teak oil would spray, the other thing to ensure is that the air you are using is very clean, I really should buy a purpose stand alone airbrush compressor but at present use my main workshop compressor but I run the air through 2 regulators and 2 filters to ensure clean and constant pressure
Good luck be interested to know how it turns out
 
Can't help with the paint but now seems a great time to stock up on your hardware requirements;);) , 60% discount is too good to pass on and not treat yourself😜
 
Can't help with the paint but now seems a great time to stock up on your hardware requirements;);) , 60% discount is too good to pass on and not treat yourself😜
This is true, but I still need to get head office approval and herself can be a bit awkward over capital expenditure sometimes..
 
I will warn immediately that the bulk of my experience is both fairly old and concerned applying colour to Airfix-style kits rather than any protective finish.

I assume when you say airbrush you mean an internal mix type, with a needle, rather than the mini spray gun style "modeller's airbrush". Is this single or double action? Single action have a straightforward button for the air, paint is controlled by a screw on the rear of a handle. Double action you push the button for air and pull it back for paint (you may or may not still have the screw).

Paint - don't need specialist stuff if thinned appropriately. Most paints should be fine. The only thing I remember being warned against was poster paint (not that I ever wanted it) - it's an emulsion of solids that are simply too coarse for the mechanism. Whether that is true in an absolute sense or judgement as to what I might try to use I have no idea. Thin your paint until it resembles "lazy water" - i.e. slightly thicker than water, sorry, I don't have a better way of describing it - and refine from there. Don't be overly afraid of clogging the airbrush but at the first sign of trouble completely remove the needle and flush the airbrush through with an appropriate thinner.

As for number of coats, I found the best way to go was ultrathin dusting coats, such that it needed several passes to lay down even a complete - yet alone opaque - layer. This is where the more basic single action models have an edge because you can set them for next to no paint and it won't move from that.

I mostly used water based acrylics and found they would be touch dry on plastic within a minute and overcoatable in ten - the coats would simply be that thin. The resulting finish was surprisingly robust given how thin it was, but again, that was about colour only rather than a protective finish.
 
I assume when you say airbrush you mean an internal mix type, with a needle, rather than the mini spray gun style "modeller's airbrush". Is this single or double action? Single action have a straightforward button for the air, paint is controlled by a screw on the rear of a handle.
It is a modellers airbrush, single button for air and screw adjustment for paint.
It was not part of an airbrush kit so did not include a compressor so went for a bigger one, not full workshop size but big enough to use a duster brush and pump up tyres - this larger compressor a cunning ploy to get herself to part with the cash for the setup ' it will be soooo easy for you to inflate your bike tyres now...'
I already have a water trap and figure since the paint should be thinned to milk consistency those cone shaped coffee filters might be OK to strain the reduced paint through. From what I read low pressure-thin paint is the way to start to learn to use an airbrush. I have an aeroplane ready for finishing but will spend as long as needed practising before putting paint to model.
 
154F0EAC-CF05-4102-A06B-40324B6C2CC0.png
 
I also own the iwata LPH-80 shown by John above.
It has resprayed several woodworking machines since I bought it using a 1.2mm jet and slightly thinned machinery enamel.
The gun is a revelation. It will spray a spot or 5" wide fan. Works with solvent or waterbased paints, and takes very little air in spraygun terms (14psi and 2.5 cu ft / minute).
It was developed at the request of (an ?) automotive manufacturer for touch up paint repairs, and is used in bodyshops for small jobs like colour matching replacement wing mirrors.

I haven't tried it for wood finishing but I expect it will be excellent for that too.

Interestingly the LPH-80 is positioned by Anest Iwata at the top of their airbrush range by size.
They have similar but smaller models in their G series that might be extremely well matched to spraying carvings if the OP takes to airbrushing.

https://www.iwata-airbrush.com/full-finish.html
@Johnhall if you havent tried this yet, do take a look at the 3M PPS and PPS2 disposable cup system for sprayguns. Adapters are available for the LPH-80 and the smallest size cups are a very good match to the small gun. They make clean up a matter of minutes with minimal mess.
They even let you to use the gun upside down !
 
Never would have thought of one of these as an airbrush, a touch up spray gun yes. They can be had as gravity or siphon. Mine is a siphon type with a capacity of about 1/4 pint. Fantastic tool for many things but not suitable for very small stuff like models.
I assume the OP is talking about a modeller type airbrush. I have used various paints in these without problems, but not normal metallics or anything high build, as they will block it. Ajs is spot on about many very fine costs being the answer. Never tried spraying oil but can't see why not, if it is the correct consistency.
 
That's an external mix type. They're good for slightly heavier media since there's so much less to clog. Don't have direct experience of them but the paint is adjusted with the screw on the nozzle. I honestly don't know how low you can adjust the paint flow since adjustment is purely by moving the nozzle in and out of the airflow.

If you haven't already done so I'd get a few spare jars to keep standard finishes ready to go and one or two plug lids to have thinner etc on immediate standby. Be aware the plug lids come in two different "slopes" since the internal mix airbrushes use one feeding at a more vertical angle.
 
I will warn immediately that the bulk of my experience is both fairly old and concerned applying colour to Airfix-style kits rather than any protective finish.

I assume when you say airbrush you mean an internal mix type, with a needle, rather than the mini spray gun style "modeller's airbrush". Is this single or double action? Single action have a straightforward button for the air, paint is controlled by a screw on the rear of a handle. Double action you push the button for air and pull it back for paint (you may or may not still have the screw).

Paint - don't need specialist stuff if thinned appropriately. Most paints should be fine. The only thing I remember being warned against was poster paint (not that I ever wanted it) - it's an emulsion of solids that are simply too coarse for the mechanism. Whether that is true in an absolute sense or judgement as to what I might try to use I have no idea. Thin your paint until it resembles "lazy water" - i.e. slightly thicker than water, sorry, I don't have a better way of describing it - and refine from there. Don't be overly afraid of clogging the airbrush but at the first sign of trouble completely remove the needle and flush the airbrush through with an appropriate thinner.

As for number of coats, I found the best way to go was ultrathin dusting coats, such that it needed several passes to lay down even a complete - yet alone opaque - layer. This is where the more basic single action models have an edge because you can set them for next to no paint and it won't move from that.

I mostly used water based acrylics and found they would be touch dry on plastic within a minute and overcoatable in ten - the coats would simply be that thin. The resulting finish was surprisingly robust given how thin it was, but again, that was about colour only rather than a protective finish.


30 year airbrush and larger spray painting dude here << Single cream consistancy, yes to dusting coats, perpendicular to each previous pass whenever possible.

Double action brushes do have thier place but generally it's for more advanced spraying techniques like feathering which is basically a dusting pass but with less paint released - double action brushes are generally used more in the art world and customs spray painting of larger items with artwork like vehicles etc where the scale of the feathering will be less impactful.

Kitty, I would recommend you follow some YT tutorials on learning how to use your spraygun, you can use pretty much any paint, but acrylic based behaves better than oils as it dries that much faster so you can get more layers and are less tempted to spray heavier if you used oil.

Overcoming the temptation to lay on heavier coats will be hard, but with practice you'll see it's absolutely not necessary and has a LOT of downsides.

Practice, practice, practice swirly shapes, lines, dots - big and smaller etc until it no longer feels "unnatural" to hold but as easy as a pen.

Product called Floetrol - buy some, just do it - will help IMMENSELY with the levelling and application properties and just make the paint behave even better than if it was thinned with water alone.

This is bascially a "hack" to help the paint get to similar behavioral properties as specific airbrush paint like Vallejo which is a "direct to cup" paint, no thinning or anything else required - but boy is it spendy! SO I do this and buy cheaper arcylic paint from art / craft shops which usually still have a HUGE range of colours but need a little attention to get them spray ready.

Old school version of this was to add a drop of washing up liquid to break the tension of the paint, but floetrol does this better and doesn't affect the adhesive properties the way WUL does.

For spraying clear lacquer / varnish, get yourself one of those spotlights with a bendy neck, not anglepoise - no good as you'll need to change the angle as you spray or get yourself a lazy susan - but having both is better.

For your models you can knock up a cradle to hold it with pins - some adjustable versions are available but a homemade one with kebab skewers and that flower attanging green stuff works great - the reason for the skewers is minimal points of contact like those triangular paint stands. Imagine those pin art things a bit like that but with less skewers spaced further apart - will hold basically ANY shape according to how you adust the skewers. - you make it by simply pushing the skewers through to an even height of your choosing, then cut off the rest. Now back out the bottoms of the skewers to about half the depth of the green block - so get a pretty thick one, and cut the skewers again making sure they are still all flat. Now you've got an adjustable throw on the skewers of half the depth of the block.

Only use as few as you can get away with, as it will leave tiny dots with each coat, so you spray, move those and add different ones, spray, move & spray, move & spray - so each pass you're going over the previous dot areas - hope that makes sense.

Just had a thought which is if you're using a stand - do the final couple of coats using the stand glued into the model and "twirl" it in your fingers while spraying the underside, again light passes.

Best spraypainting hack ever.

Do this for a while, then buy a better brush - DeVilbiss, Paasche (spendy), Iwata are all tried and tested brands used by professionals.

Oh and I prefer a side feed cup to a cup fixed to the body on the top, this allows you to get better angles of attack as the cup can rotate 360 deg, very handy!

Oh (again) - PROPERLY CLEAN YOUR AIRBRUSH EVERY SINGLE TIME - I MEAN IT - a gunked up airbrush is good to no-one and significantly harder to clean out.

After shooting paint I generally blow through some water a couple of cups, then half fill the cup with Kitchen degreaser - cillit bang, orange oil something that's designed for heavy duty grease cutting, this will eat through residual acrylic paint aggresively - spray it in then shake it about a bit, shoot this then do that again, but before shooting it, backwash it - which is spraying while having your finger over the needle - akin to gargling if you will, this will agitate what's in the body between cup and needle, if you have an open cup you'll get some spatter so do it over some kitchen cloths, old towel etc- shoot that and do it again, then fll again and let it sit for a bit, shoot again then rinse a couple times with water.

Every few times you've sprayed, disassemble the gun entirely and soak in degreaser for a while, then rinse and reassemble, paying particular attention to the needle.

Sounds like a lot but hardly takes any time at all, you can buy a special spray jar designed to shoot all these dregs into rather than into the air or a sink, but that's your choice.


With a bit of practice you could quite easily add some basic markings to your models, even camoflage with the wood as the base.

Google Alclad - you'll want to try this. Trust me, but make sure your prep work on the model is FLAWLESS or it'll look rubbish.
 

I have one of those, mine sold under the name Humbrol, but as said above, all those external mix "cheapo" guns are much of a muchness I think. But I would say IDEAL for spraying lacquers, varnishes, etc, and single solid colours, both water and oil-based. And if you have a set of nozzles and needles for it (mine came with fine, medium and heavy) it's surprising how well they can do fine line stuff too.

They don't need much pressure (2 Bar is more than enough) and the needed flow rate is quite low too (my airbrush/es are very well driven with a very small, almost silent, diaphragm compressor - mine by Badger). All you need is a water trap and a longer than supplied flexible hose (NOT the horrible, short, hard-ish plastic type that came with mine)! A hose of 1 Metre+ length will happily smooth out the pulses down the line, so the compressor doesn't even need a tank! That's my own fairly extensive experience anyway.

I also have a "touch up" gun, in my case a SATA, as recommended by the highly experienced guys in the Swissair paint shop (who back then spent a LOT of time fully repainting and touching up full size airliners, Boeing, Airbus, etc). That does need a bigger, higher PSI and flow rate compressor and a tank though (plus moisture/oil trap of course).

In both cases, again based on the paint shop guys' talks, a viscosity cup is essential and takes all the guess work out of creating repeatable mixes in whatever medium you use.

Just FYI, I only ever used the SATA gun on medium to large flying models, about 2 Metre wingspan and up.

For all my small flying models and toys (similar sizes to your aircraft models Kittyhawk) I found the above external mix "Humbrol type" airbrush ideal, though I must also confess that for a birthday some years ago, SWMBO also bought me a twin needle internal mix airbrush (in my case the Badger 150). That really IS good for really fine lines, etc, and can lay down really fine/thin coats (ideal for japanese tissue-covered indoor flying models). But it's frankly a bit of an overkill for most of my needs - those types of airbrushes are used mainly by professional artists, custom car painters, and the like. My own airbrushing skills do NOT extend anything like that far!

I should add that all the above was some years ago, and apart from Paasche, and De Villbis, Badger was just about the only good brand available back then. Since then I understand that several Japanese airbrushes are on the market (both external and internal mix) and from the little I've seen/read, they seem to have a generally good rep, AND with lower prices than Badger, etc. But I stress I have never used any of those, so nil personal experience.

HTH

Edit for a P.S:
Agree almost 100% with what rafezetter has to say in his post above. Areas of difference? 1. Acrylics CAN look a bit "heavy", (and for flying models, generally ARE, but irrelevant here of course). But they do dry fast, in some situations, too fast. 2. IME, acrylic clear varnishes "never" seem to be as "tough" as oil-based. 3. Perhaps try cellulose, no real problems apart from smell, toxicity, and fire risk, plus "blushing" if spraying in humid atmosphere. But VERY easy to clean with thinners (from car body shops).

But IMO, he's got so many points dead right above, especially the bit about THOROUGH cleaning EVERY time (I tell you, you haven't lived until you've tried to get EVERY speck of dried paint out of a dual needle airbrush)!!!!!!!! :mad:
 
Last edited:
Thank you ajs, rafezetter, AES for the truly informative replies above.
Today is playing with the airbrush day and yesterday I prepared a bunch of wooden bits to practice on, some with sanding sealer already applied and sanded, some sanded bare timber.
There is a degree of trepidation and at my age I hope I get the hang of it before I run out of time.
I purposefully chose the simple bottom feed gun on the premise that it's easier and more forgiving for a novice and my work is either masked off black paint areas or clear coat, no feathering involved.
I was planning on using enamel paint because I don't know if acrylic would behave itself when overcoated with the Briwax teak oil - I want to keep using the teak oil because I like the finish it gives.
Briwax is made here under licence so asked the manufacturer if his teak oil could be sprayed, suitably thinned. He replied 'I don't see why not' which means he doesn't have a clue, do today will tell.
 
Back
Top