AB leaking paint when thinned too much

[GU-11]

I was AB'ing some test spoons today, and noticed that the nozzle leaks paint (lets out a thin stream of paint even when I don't suqeeze the trigger) when I thin the paints up too much. This ONLY happens when the paints are really thin. Paints thinned in 1:1 ratio aka "skim milk consistency" doesn't do that.

Should this be happening?

According to online articles, this supposedly happens when either the nozzle or needle is clogged with dried paint, but I always take my AB apart for a thorough cleaning after every session. I even check for dried paint particles in the nozzle, central block and needle through a magifying glass to make sure.

The only possibility is that the needle wasn't pushed in enough, but I'm hesitant to try pushing it too far in for fear of damaging the nozzle. If it's normal for AB's to leak when the paints are too thin, then that's fine. Then again, I hear that you can even spray inks out of an AB, so that shouldn't be the case, should it?

Any advice is much appreciated.

[kyekye]

It sounds like the end tip (the tube that holds the needle at the tip) is damaged by needle or paint. This happens during cleaning or by trigger habit (let off with spring).

If it's clogged, the air leaks from other side (top) in most cases.

Edited April 12, 2013 by kyekye

[GU-11]

Thanks for the info, Kyekye!

Come to think of it, I do remember doing very short pulls on the trigger while painting when the leaking suddenly started, and that might have damaged the nozzle aka end tip. These airbrushes are WAY more fragile than I thought they'd be.

I was afraid I'd have to replace some AB parts. First the rubber o-ring, and now the nozzle. This is getting expensive.

Any advice on how I can prevent from accidentally damaging my AB again?

Edited April 13, 2013 by GU-11

[kyekye]

Yeah those AB parts are expensive. I've been using the same guns (2) for more than 10 years - but that's
after damaging and getting rid of one before that. Back then, they didn't sell parts separately, so Only option was to get a new gun.

I don't know your skill level, so I'll put down just general notes.

*My advice is get a good one and take good care of it. It sounds simple, but hard to do.

*As long as you clean it after each use and do a full cleaning once a year (disassemble and clean parts), it should last long time.

*Lacquer or Enamel based paints are easier to clean, but unhealthier than Acrylic paints. Acrylic paints are water based, but becomes problem once dried up. So clean quickly after each use.

*Never ever push the needle in excessively.

[GU-11]

Many thanks, Kykeye!

I guess I'm still at beginner level. My AB'ing techinque is still pretty rough, as evidenced by my damaged nozzle. I didn't think I could damage an AB just by doing quick pulls on the trigger. FYI, I'm using a gun-type AB, which comes with the Tamiya Spraywork Basic Compressor. Is this AB good enough, considering my rudimentary skills?

A few more questions:

I always do a full cleaning after every spray session. Does this actually do more harm to the AB than good? I was just thinking that all that disassembling might add to the wear and tear on the airbrush. Every time I reinsert the needle, there's a risk I might push it too far into the nozzle. I'm ultra careful whenever I do so, but I hate running that risk every time I clean my AB.

Can I do a "flush through" clean using water (pressing your finger to the nozzle and squeezing the trigger to back flush the AB)? I usually use Tamiya's AB cleaner, but it's getting ridiculously expensive. Is methylated spirits a good substitute? I tried looking for isopropyl alcohol in pharmacies, but they only sell saline for disinfecting wounds (well, Malaysia IS a Muslim country).

And the most important question: What's the "proper" way to pull back the AB trigger? I have a habit of doing quick passes while spraying, although I don't simply let got of the trigger and let it spring back. Should I do slower passes and release the trigger slower? Many modelers I've seen on youtube seem to do slower passes and I'm used to. But if it helps keep my AB healthy, I may have to change the way use my AB.

[EXO]

You're gonna run into a lot of crap you're not prepared for. I've been doing it for a while and while I've gone passed the beginner's stage, I'm still thrown for a loop. I'm trying to switch brands of paint right because the amount of paint i've been using lately is just ridiculous. And while most of it has been going good one small thing that goes wrong puts me behind by a lot. I just ordered a hose and it came defective. Now I have to wait for another one while the one I'm using leaks out as I'm trying to paint.

Anyway, don't let that dishearten you. I'm just letting you know that most of what you're going to learn are thru misakes or just part of the learning process. I've had my first ever airbrush, an Iwata-C, for 20 years and when I bought it, I was a broke student, but it's lasted me all these years. I guess it's durable and in a way spending a lot then has saved me money all these years.

I clean out by AB every week or as soon as it starts to shoot funny. In between colors or when I need to stop spraying for a while I run some windex thru it and then some water. When there's some stubborn paint that is dried up I get some acetone and a swab. Acetone is some nasty stuff though. Don't spray it around and put some gloves and your mask on.

Didn't you say you had a part missing? Could it be leaking because of that?

[GU-11]

Thanks for the pointers and the pep talk, Exo. Seriously, I appreciate it.

Airbrushing is a very new thing for me (been using rattle cans up until recently), and the way parts keep getting dinged despite my best efforts at being careful...I felt like an absolute klutz. But from what you've told me, I guess AB'ing is something of a school of hard knocks.

Let me get this straight; does a better quality AB (read: expensive) mean better durability? If that's the case, I might have to upgrade my AB. Thing is, the compressor I'm using can only be used with selected Tamiya AB's with removable air valves. It's either the HG or the ultra-expensive trigger type. I'm fine with the HG one, since it's far more affordable, but I've gotten so used to trigger type AB's that I'm not sure if I want to start using a traditional pen type one.

Honestly, are pen-type AB's harder to use than the trigger ones?

As for the missing part, it's a double o-ring that was supposed to seal up the needle. I ordered some replacement parts from the local Tamiya store and there are no more bubbles in the paint cup anymore.

This time around, it's the nozzle aka end tip that's been dinged. I looked at it through a magnifying lens, and one side is slighly flattened; must had accidentally caved it in when cleaning it the last time. The funny thing is, when it started acting up the previous time, I replaced the old needle with a new one, and the paint stopped leaking. This time when I did the same, it didn't fix the problem. Strange.

One more thing: can I substitute Windex with Kao Magiclean? Windex isn't sold here. I've heard that window cleaners are good for removing acrylic paint, but when I tried using some Magiclean to remove some paint from a part, it did nothing. It took a Gundam marker "eraser" (basically a marker containing thinner) to remove it.

Edited April 13, 2013 by GU-11

[MacrossJunkie]

I use plain old 70% isopropyl rubbing alcohol to flush and clean out acrylics out of my airbrush (a Badger Renegade Velocity). Paint generally comes right out and the alcohol easily takes off dried on paint just rubbing your finger on the paint and the alcohol doesn't leave any residue behind. I also use one of these things, http://www.amazon.com/gp/product/B000VADIVC/ref=oh_details_o07_s00_i01?ie=UTF8&psc=1, to spray into and hold my airbrush.

[EXO]

he mentioned that ISO isn't available in his country...

Not sure about that brand of window cleaner. You can just use the thinner but any window cleaner with ammonia should do the trick.

I need to get one of those cleaning stations. Right now since I don't have a sink I'm putting everything in a giant glass container and hold a piece of towel on top while I spray into it. lol.

[MacrossJunkie]

Sorry, I missed that. I would have thought it would be a pretty common item. How about vodka?

[EXO]

No thanks, but I'll take a beer!

Badabump! Psssshhhh!!!!

[GU-11]

Thanks for the replies, guys!

The problem with finding ammonia-based window cleaners is that they aren't always listed on the label. I looked through a few brands on the shelves, but mostly they just say surfactants and solvent.

Would methylated spirits do the trick as an AB cleaner? I'm not sure what it is, but someone reccommended using this as a thinner for thinning acrylics.

[MacrossJunkie]

You'll want to be careful with using ammonia with your airbrush. If it has brass parts or chrome plating, the ammonia can corrode the brass or ruin the chrome plating.

A quick search on Google tells me methylated spirits should work.

Edited April 14, 2013 by MacrossJunkie

[EXO]

Hmmm. Wonder if rinsing out with water is the reason my airbrush is still like new. But I was already thinking of getting something else to clean with. This will make me try to figure out what I'm going to replace windex with. See GU... I'm still learning too.

[GU-11]

@MacrossJunkie: Thanks for the heads-up! Yeah, I've heard heard a lot of debates on ammonia. Some say that ammonia-base cleaners are suitable only for back-flushing, and you should never soak AB parts in it. Seeing as it's hard for me to know for sure which brand of window cleaner has ammonia in it anyway, I'll methylated spirits instead.

And I'll seriously have to think about getting a cleaning pot for my AB.

Hmmm. Wonder if rinsing out with water is the reason my airbrush is still like new. But I was already thinking of getting something else to clean with. This will make me try to figure out what I'm going to replace windex with. See GU... I'm still learning too.

Good to know that rinsing with water is actually good for the AB. I usually backflush the AB with tap water before disassembling and cleaning. Used to backflush with Tamiya AB cleaner, but it gets pretty expensive after a while. I now dab some AB cleaner onto a paper towel or q-tip to clean the needle and central block--lasts much longer that way.

Yeah, I guess one never stops learning when it comes to airbrushing.

[MacrossJunkie]

Yeah. I've read that you shouldn't ever soak AB parts in any sort of solvents or solutions anyway, not just ammonia. A few of the reasons were that the paint could be get dissolved then redeposited in other parts of the airbrush, particularly difficult to clean out would be the air valve if it got in there. The paint could also crystallize in those areas and further make it more difficult. Lubricants could get stripped away (not as big a problem since you can buy AB lubricant and should try to lubricate it now and then anyway). Lastly it could ruin the rubber sealing o-rings or the needle packing ring, either swelling or dissolving or making them brittle.

How you're cleaning it now seems fine with backflushing and cleaning the needle and such with the tamiya AB cleaner.

Edited April 14, 2013 by MacrossJunkie

[Noyhauser]

There are different ways. I'm more of a minimalist, but then again I use Iwatas which are pretty well made.

A lot of people will fully disassemble their ABs, and clean parts individually after every usage. I don't think that's necessary; maybe once every few months usually suffices. I use lacquer paint thinner, which is one of the strongest general thinners available.... it blows apart any remaining acrylic residue.

I fill the cup up, spray a bit out, then put my finger over the end of the nozzle, to backflush as you do. I repeat that spray and backflush process a few times, until the cup is empty. I then rinse out the cup with a bit more thinner and a paper towel... and remove the needle as well. I let it dry out of the gun, and reassemble it when I want to use it next.

Edited April 14, 2013 by Noyhauser

[GU-11]

Thanks so much for all the great advice!

Speaking of AB lubricant, is Vaseline good for lubricating needles? Tamiya doesn't sell airbrush lubricants and the only place I can find a ready supply of modeling supplies is at Tamiya's official store.

[MacrossJunkie]

I'm not sure. It might possibly work. I don't know if it might be too thick and cause clogging or not.

Could maybe try mineral oil or olive oil.

[Noyhauser]

try searching for iwata's lubricant (superlube). It works really well.

[GU-11]

@MacrossJunkie: Olive oil? If it does work, that'll be perfect, as it's easily available.

@Noyhauser: I heard that Tamiya airbrushes are manufactured by Iwata, so hopefully the store will sell lubricant from this brand a well.

[MacrossJunkie]

I don't see any real problem using olive oil to lubricate other than it won't be as long lasting as lubricants made for that purpose, but it just means having to lubricate the needle or trigger more often. If it's easy to get, then so much the better.

[GU-11]

My only worry is that the thinner and alcohol in the paint might react to the oil. If that's not a problem, then olive oil will be perfect! Since I clean my airbrush very often (the instructions say you can use back-flushing to clean the AB for 2-3 spraying sessions, before needing to disassemble and clean it), reapplying the oil frequently is no problem.