Hi - I am reasonably new to airbrushing and seem to be having a few problems so would welcome some advice.

I am currently painting the Trumpeter 1/48 Sea Fury and using an airbrush and compressor.

I thought I had thinned the paint enough as when I painted the underside it seemed ok although the airbrush did seem to lose the paint so I had alternate paint/air.

On the upper surface the pain sprayed out gritty or not at all - what am I doing wrong? I am mixing thinners with on this occasion humbrol enamel paint at 50:50

Also is there a way I can re-spray the model to get a smoother finish?

Many thanks
Chris

Hi,
when you increase the paint/thinner ratio you should also increase the pressure.
That is, the thicker the paint, the higher must be the pressure.
Anyway, try to use a bit more thinner and see if you can get a smoother finish.
I read somewhere that the ideal paint thickness is somewhat like milk, and it actually works for the main paintjob. Just regulate the pressure and test before spraying on the model to achieve a good result.
You will need lower pressure and very thinned paint in order to draw exhausta stains instead.
Also try to spray a bit closer to the surface as thinner tends to evaporate before the paint reaches the surface, so what you actually spray are thick droplet of paint. This will cause a non-smooth surface or an "orange peel" effect which is quite visible with gloss paints. Always move the airbrush to avoid the colour to build up excessively.
I noticed that painting almost or totally flat surfaces (i.e. the wings) easily ends up in gritty surfaces if you don't pay attention to your pressure/thinning ratio. Anyway, it's all about trying and trying.
I think a good gloss coat, or Future floor wash if you can get some (I wish it was available here in Italy), will help you smoothen the surface. You cold also use very fine polishing sandpaper or Micromesh pads. No idea on how to remove enamels from then model as I airbrush only acrylics (which can be removed with Windex, alcohol or even soapy water).
Don't worry, these are ordinary difficulties that I also experienced, once you learn you'll master the airbrush with no problem and create great effects!

Ok this is very good advice so many thanks! It makes sense about being closer to the model and I will try this first. I think you are right that acrylic is easier to work with - I have used it before with reasonably good results.
thanks again
chris

You're more than welcome, mate!
I know it might be difficult to spray close to the surface. You don't need to spray a couple of centimeters away from it, but neither too far from the surface! Just make some pratice and you'll get the hang of it!
As for the kind of colour, I don't use enamels for airbrushing because they smell too much, and I don't have a dedicated working space. My favourite paints are Tamiya and Gunze acrylics, which are not less toxic, but don't smell as much and dry within seconds (at least flat colours - semigloss or gloss colours do need more to dry without leaving fingerprints on the model).
They can be thinned with their own thinner, alcohol or even water. Some modellers use lacquer thinners which seem to be indicated for gloss paints (try to spray Tamiya's clear gloss paint with Tamiya acrylic thinner, you'll get a grainy surface for the reasons I told you before).
A much safer solution in terms of toxicity are Vallejo Model Air acrylics, which come pre-thinned, or Lifecolor ones, but they both need their specific thinner to clean the airbrush. I tried them twice and used alcohol to clean my hardware... never more!
Anyway, I can't but repeat that a good practice will be useful, as well as a thorough cleaning and maintenance of the airbrush. If you handle the AB carefully and lubrify the needle after cleaning definitely it you will definitely have good performance, will not experience trouble nor need spare parts, which are expensive and sometimes difficult to find, especially for those made by unknown brands.
A further advise: if you are going to use acrylics, DON'T clean the airbrush with Windex as it contains ammonia, which will remove the chrome coating.

Yes I like the Tamiya paints also but havent tried the others but will give them a go. I know what you mean about the toxic smell from enamel paints! I've had to airbrush with them in the garden as my wife goes bananas at the smell in the house!
My next challenge is to airbrush camouflage - I used paint masks for a Hurricane last year but they are limited in range so I need to take the plunge. I guess though if I use acrylics I can start again if I need to.

If you want to spray camo schemes you could as well try to mask the edges with products such as UHU Patafix. If you spray carefully, trying to keep the airbrush perpendicular to the surface, you can get nice feathered edges. A good solution if you don't feel like spraying freehand!
I think also enamels can be removed allowing one to restart from zero, but I think you need some kind of dangerous chemical solution! Acrylics are much easier to remove if necessary!

Don't get the idea that there is such a thing as a "safe" paint; it doesn't matter what you spray, breathe it in, and it can do damage to your lungs, so make sure you use a face mask, preferably of professional quality, with replaceable cartridges.
If you start chopping and changing your paint, you risk never finding peace, since you'll always blame the paint, not your technique. Continue with what you've started, and, once your finishes are acceptable to you, then is the time to start experimenting. Until you're confident, always use the manufacturer's recommended thinner; after some successes, then is the time to start playing with other materials.
Get a flat sheet of plasticard or smooth-surfaced cardboard, and start spraying (or trying to spray) a smooth area of a single colour.
First, never point the gun at the subject, and press the trigger, since you risk a blast of colour just where you don't want it; start off the surface, and sweep the brush onto it.
Spray from no further away than the length of your hand, and do not bend your wrist; using your forearm and hand in a straight line keeps the brush at an even distance from the surface.
Spray one pass, and examine the result; grainy, or rough finish = too far away, since the volatile thinner (which is designed to evaporate after it's arrived on the model) is evaporating on its way to the surface, and almost-dry paint is arriving on the model. This is especially true of some acrylics, which is why I would advocate using the slower-drying enamels, first, until you've built up some experience.
If your first pass has worked, you should see three almost distinct lines; in the centre should be a solid line of colour, smooth, and with no drips or runs (sure signs of over-thinned paint.) Either side should be two more lines, less distinct, and fading to nothing at the extremities.
Once you have a set of lines which look acceptable, spray your second line slightly above or below the first (doesn't matter which,) so that the centre line covers one of the outer lines of the first trio. This is called "spraying to the wet" (so you can impress your friends with your knowledge If you can now see a broad band of solid colour developing, keep going, until the sheet is covered to your satisfaction, then leave it to dry (remembering to clean out your brush and cup, with a blast of thinners, first.) There's nothing quite as debilitating as having to clean dried paint out of an airbrush.
Hold the sheet up to the light, and look for streaks in the surface, which can be easily covered by a fresh application of paint, but do it now, not in a few days time, when the paint has had time to lose some of its consistency, even colour.
Once you've mastered the technique, you can graduate to the model, but always try to spray at right-angles to the surface; spray at an angle, and you risk having the overspray (which you will always get) bounce back off another vertical surface, and, because it has started to dry, mix with your spray, and again give you a gritty finish.
Edgar

excellent advice - thanks Edgar.

So I prefer Tamyia paints and last night was experiemnting with matt Dark Sea Grey. The spray seemed to come out even yet some areas dried matt and some dried with like a lighter sheen. Have a mixed too much thinner?
thanks
Chris

thats a great idea for camouflage and I just watched someone use it on Youtube! I liked the photos of your armoured vehicles - they look great.

Too much thinner usually shows up as runs, or a finish that it almost translucent, where you can still see the plastic through the paint. It's possible that you didn't stir the paint thoroughly, so some of the flatting agent wasn't dispersed properly, but likeliest is (probably) uneven coverage, and another coat will sort it out; it's difficult to diagnose by guesswork, though. You mustn't expect perfect results from the word go; it took me six months (and a lot of advice from a furniture polisher on technique) before I began to see acceptable results. There's no substitute for practice.
One of my reasons for using Xtracolor or Humbrol is that it means that I use the whole tinlet, in one go; this means that I know that the paint is thoroughly mixed, and there's no residue left in the tin. It will sound wasteful, and expensive, to some, but I'd rather "waste" half a tin of paint than a £30 model.
Edgar

ok thanks again. I have used water instead of thinner this morning and although I over did it with the water the results so far are much better! As you say I need to keep at it to improve and I need to learn the art of patience which sadly lacking at the moment!

Also try alcohol! It's the cheapest solution if you run out of thinner. Of course, as Edgar wisely suggested, DO wear a mask!

I don't suppose you guys have any good ideas for painting aircraft wheels?! With WW2 aircraft getting the tyres painted evenly around the aluminium is tricky I find!

Painting the wheels It is something I do HATE, but I recently found a solution.
1) paint the wheel with aluminium
2) apply some diluted black around it, as a washing
3) brush black on the tyre

I tried this method with Vallejo's acrylic Black Grey and the results are very satisfying.