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So I recently got into airbrushing my models. Perfect timing too, the amount of models I had accumulated that weren't even basecoated was overwhelming, if not for the godsend of an airbrush I probably never would have convinced myself to start painting them! Anyway, earlier this week I posted about finding a cheap airbrush compressor. After finding that spending a little extra money is worth it in the long run when it comes to compressors, I decided to deal with it and bought a decent one - needless to say, I am very happy with it! However, I've had an interesting issue that I thought would be resolved by using a compressor rather than a propellant can, but unfortunately it has not. I have an Iwata Neo airbrush, dual action and gravity fed. Sometimes when I'm using it, the paintflow just altogether stops as if a clog has occurred. The interesting thing about this is that if I push the lever down (releasing the air) and then pull it back (which SHOULD release the paint), nothing happens. But when I push the lever forward again, a small amount of paint will come out very quickly. This can be repeated, if I pull and push the lever back and forth, a small burst of paint will to spurt out each time as I push the lever forward again. If I clean the airbrush very thoroughly, it will usually work for a while, but it inevitably starts again. Oh, and on a side note, oftentimes when this starts to happen there is no visible clog in the airbrush. So, whats the deal? Is there something up with my airbrush? Is my paint not thin enough? Am I just THAT terrible at cleaning clogs? Honestly, as a total beginner to airbrushing, I am clueless haha! Thanks for any help you can offer!

George

What paint are you using? If it's water-based acrylics like Citadel, Reaper, P3 etc then you're probably experiencing tip dry. It's paint drying on the needle. Click on the link for some tips to take care of it.

You can reduce how often you get tip dry by using a retarder medium and thinning with airbrush medium instead of water, but you'll still get it with acrylics because they dry so fast.

vallejo does this to me all the time.

then you spray citadel and it's as smooth as silk.

I get similar problems sometimes , things to help are : thin paint properly , don't use anything with lumps or flakes of old paint EVER, and if it happens I tend to clear it by sealing the nozzle with my finger until bubbles blow in the paint , that usually keeps me going for another five minutes.

Acrylics do dry really fast tho , watch the paint build up on your needle after 30 mins or so.
With enough thinner ( i generally get by with a mix of water and alcohol 50 /50 ) you will minimise cleaning and down time , honest !

I'm no expert however !

I use citadel paints, at least for this specific paint scheme. Doombull Brown is far too perfect for what I want in my Tau army for me to use a different brand! Thank you for all the fast responses. I went to the link that Arschbombe posted, and tried all the suggestions they had posted there (minus the retarder medium, I obviously haven't had time to run out and get that yet). At the same time, the fact that those cleaning tips aren't working makes me think that it may be a different issue. I removed the whole needle and there was nothing dried on it, but I cleaned the entire thing, put it back in, and the problem persisted. I tried the blowing bubbles in the paint, and that unfortunately didn't work either. Could it be at all possible that my airbrush itself is defective? I bought it around a week ago, so I could almost definitely get it replaced if that was the case.

Just for further details, I am basecoating 90% of my Tau army Doombull Brown. It has happened plenty of times with that color. The other 10% (the vehicles) I am priming black, spraying White Scar patterns on it, and then coating them in one of the Badger ghost tints. This has occurred with all three of these paints/mediums, even with the ghost tint, which is almost as thin as pure water is anyway. Ghost tint also takes some time to dry, so that makes me unsure as to whether or not the problem truly is due to drying paints. Again, I am far from an expert, so this is very confusing to me.

EDIT: Just realized something that could be very important! It is not just paint that becomes inhibited. The issue with paint is as I described above, where it completely ceases to flow and will occassionally burst out small amounts of paint when I push the lever forward. I only just realized that the air, while it continues to flow, sounds and feels very inhibited. I feel the need to say again haha, I am not an expert, but it seems to me that this could mean that paint is flowing back into the areas where the air is supposed to flow from. Could this be the case, and if so, is that normal?

EDIT #2: I think I confirmed that there is indeed paint gathering in the areas where the air is supposed to flow through/from. Upon completely disassembling the airbrush and beginning to clean it, a considerable amount of paint rushed out of the back of the airbrush, spouting directly from the location of the valve that the air comes through. So, if that is abnormal (which for all I know it might be, but it seems odd to me), then that is likely what is causing my problems.

Well mate , firstly , what air pressure are you on ?

Second , maybe your needle is too fine , I once bought a really fine needle which was only good for inks and couldn't ever get paint thru it !

I try and avoid GW paint , I use Tamiya and Vallejo all the time,with good results, but will mix all kinds together for the right colour I need.

I don't usually have problems unless I use old paint with lumps or flakes of dried paint in it.

Since I got my compressor I've been doing 30 psi for the basecoating I've been doing. Before that, I was using propellant cans that I had leftover from when I was using a terrible airbrush, so I can't accurately say what psi those were, but the issue occurred with both the cans and the compressor. The needle i am using is .35mm, and the paints are brand new.

I generally get along fine at 20-25 psi so 30 shouldn't be a problem.

I have a cheap diaphragm compressor that needs a expansion tank ( an old air can) fitting in the air line to stop it "spurting" at low pressure but I'm not sure thats ur problem.

.35 mm should be OK for good paint too , so in short I'm not sure whats going on there! sorry !

Any good hobby shops near you (i.e. planes , trains, and automobiles ) ?

I've got a Hobby Lobby (where I bought the thing, thanks to their 40% off coupons), a Hobbytown USA, and a store dedicated completely to art supplies, and I believe they have some things related to airbrushing as well.

Hmm , well in that case it may be worth getting a fella to give it a go if they have that kind of set up , i.e. a hobby store that has a compressor, does spraying etc to see how it runs for someone else and take notes if it works fine !

your nozzle is clogged. potentially by tip dry, or lumps in paint, or just paint drying up in the tip.

Acrylics (all brands - it doesnt matter who made it) suffer greatly from tip dry, the thinner you use can assist or hinder you on this front.
Its because acrylics dry remarkably fast, and your forcing lots of high pressure, dry air passed it.

Solution = to strip down the airbrush, and clean properly. (Should do this after every session anyway)
Check youtube videos for advice on how to correctly dismantle and clean the components. I'd explain it but a video is out there (probably lots) and it will be much more clear to see than read.

What are you using to clean?
When paint shot out the back of the airbrush... was that while removing the needle? sounds like there was a lot of paint built up around the needle seal. DONT REMOVE THE SEAL!!! you likely do not have the tooling to align it back into place - its a special screw driver with a prong that holds things centered as you screw it into place (atleast it is on my H&S brush)

Sounds as if youve neglected to rinse it out after each usage, and that paint has been building up. Maybe also not thinning it enough; when its adequatly thin it rinses out kinda easily without leaving any thick gloop behind.

Someone above mentioned 0.35mm being good enough for the paint... 0.2 is good enough! just need to thin the paint properly.
Nozzle size directly relates to paint viscosity and air pressure needed and results in a different (smaller) spray pattern. Almost all paints excpet metallics will go through a 0.2mm nozzle (tried and tested with my own hands before anyone tries to say thats wrong)

If the nozzle is clogged, the air pressure will fore the paint out of anywhere else it can. Usualy back up out of the paint cup tbh. But also back along the needle channel tot he seal, if that seal fails you, then youl get paint all in the trigger assembly and have a real cleaning job on your hands.... that or have an annoying sticky trigger for ever.

I agree that the nozzle may be clogged. Try cleaning it out with a needle after soaking it a while in Windex.

After which, make sure your needle is seated properly (with the nozzle and nozzle cap on, unscrew the needle chuck and gently push the needle forward until it seats in the nozzle)

Try spraying only water then. If nothing comes out or the water comes out in spurts, there is either still a clog or there is a problem with the nozzle.

Echo'ing above - clogging.

I would reccomend using some airbrush medium if you aren't. You can buy small, expensive bottles of it from gaming stores (Vallejo makes a good one), or huge gigantic bottles from an art/airbrush store/mail order. I personally get huge bottles of Golden Airbrush Medium.

The neat thing about an airbrush medium that is different than thinning with water/windex/whatever, is you can't thin it too much. You can literally go 90% medium, 10% paint, and it'll work - and texture wise, you're basically spraying water at that point. For reference, I usually do about 60% medium/40% paint.

I'd give the brush a REALLY good cleaning - soak the nozzle in some acetone and scrub it out. Maybe even soak the main airbrush body in water for a bit. Then try out the medium. You won't be dissapointed.

Again, thanks so much for all the advice guys! I do clean my airbrush very thoroughly after each use, so I don't think the issue is arising from lack of cleaning. I may not have described it well enough, it wasn't as if the entire back of the airbrush was filled with paint, but it was more than just a few drips, enough for me to find it surprising. I have, however, dealt with paint gathering in the trigger assembly, and it WAS an awful cleaning job, so it seems that the clogged nozzle forcing paint through valves is likely.

To clean the airbrush, I've been rinsing with water (which, as I've been using citadel paints, has done the job pretty well), and after I get the water to spray clear, I spray some airbrush cleaner just to be on the safe side. If I want to clean the whole thing, which I usually do after each session (which have been short due to this problem) I break down the whole thing and rinse them all, and ensure that there is no dried paint on them. The paint DID rush out after I had removed the needle, so I suppose that means that paint could have gotten back there due to that as well. When it comes to removing the needle seal, I know what the seal is and does, but I have no idea where it is or even HOW to remove it, so that isn't a huge concern haha.

I will buy some airbrush medium today. Does it do the same things as the aforementioned slowed mediums? If this really is clogging, which it certainly seems like it is (you guys all seem like you really know your stuff), then I can say for sure that it is clogging way more often than it should. A little clog every 5 minutes that just requires the tip to be cleaned off is acceptable, but a huge clog every 5 minutes that requires complete disassembly of the brush is just making the whole process counterproductive. I'll let you guys know how it goes!

Seems like your doing mostly the right thing.

Though, you should get some solvent based cleaner; acetone, IPA, some branded airbrush cleaner... whatever it happens to be. The important part is that it will dissolve dried paint. Water will not.
Pure Acetone probably works the best, but be wary of it eating away at seals. IPA can be a bit kinder to the rubber.

hehe the needle seal is approximatly int he center, accessed from the back of the brush once the trigger assembly and needle have been removed. It screws in with a screw driver... but I'd say leave it alone, because putting it back in straight is impossible without the tooling, and will wreck a good brush if its wonkey.

It sounds as though your needle seal is either damaged or misaligned, I have had this problem on some of my full size (automotive) spray guns, Which has led to paint in the airways and erratic spray patterns. Try getting the seals replaced. If the airbrush is new the manufacturer should do this for free. In any case, contacting the manufacturer is probably a good idea.

You've got some great advice already... and you are experiencing, very typical problems.

I'll repeat - use a PROPER medium to keep that tip wetter longer, I use Liquitex Airbrush medium because it does just that far more efficiently than most mediums and especially hack thinners like windex/alcohol... then of course, get used to painting with thin paints in your AB and practice, practice, practice (start on terrain!).

Cleaning the AB regularly, and thoroughly, is unfortunately a REQUIREMENT... this is my favorite site: http://www.airbrushguru.com/how-to-rinse-gravity-feed-airbrush-after-spray-session.html

Best of luck!