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Discussion Starter #1
I am a novice at using an airbrush but have successfully used it several times since I got it. After the last use I disassembled and cleaned it. When I went to use it today, it would not draw--instead it is blowing bubbles into the paint jar. Any ideas out there about what the problem might be?

The airbrush is a Paasche VLS internal mix double action.
 

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The airbrush is blocked somewhere still. It could be anywhere from the tip to the paint intake. Most dual action airbrushes are really complex, difficult to clean and maintain. For an airbrush novice, I'd say set it aside and get yourself a really basic single action airbrush to work with for a while, like a Badger. Much easier to clean and maintain and, most importantly, use. If you don't want to go that route, I'd say strip this airbrush down again. Let all but the nylon parts soak in lacquer cleaner for a day or so. Then check the model painting forum here to see if there is any info on cleaning and reassembly and check out the Fine Scale Modeler site for airbrush maintenance. Most of the time, and possibly now, all you need to do is clean the tip. The best way to do that is to carefully remove the tip and head run some dental floss called Super Floss through both. With a single action airbrush you can run Super Floss through the whole paint path w/o taking anything apart. Pipe cleaner is great for keeping the paint jar and tube clean. I really, really, really don't like messing with my dual action airbrushes (Badger, Paasche and especially Iwata) so I only disassemble them once every few years. Otherwise I just keep them really clean by blowing a paint cup's worth of lacquer cleaner through them (and into a paint booth) after every use.
Also important: virtually no commercially available modelling paint booth meets gov't standards for safety. And many are just total garbage. If you're using a paint booth (absolutely essential with an airbrush) and you can smell paint or lacquer cleaner as you spray, your paint booth isn't working properly and you're in danger. Check the Fine Scale Modeler site to see if they still have instructions on calculating air flow and building your own safe paint booth.
Also, if you have a Yahoo ID, by co-incidence a new discussion has begun today on the space modellers group about airbrush recommendations:
http://groups.yahoo.com/group/space-modelers/messages/82280?l=1
 

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Discussion Starter #4
Actually, I was preparing to spray Future (which I have done successfully several times before).

Thanks, Starseeker. I will break it down again and see what I can find.
 

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I had that happen once ... except it didn't just bubble out the paint jar, it shot a jet of paint out through the air-hole in the cap right into my face. (Luckily my eyes slammed shut before the paint hit them.)

Good luck on the cleanup.
 

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your airflow is being blocked somewhere, so the air is coming out through the color cup instead of the tip. (by the way, this comes in real handy when cleaning your airbrush. after youve sprayed some of your cleaning solution through the airbrush, put your finger over the tip and spray. this will force the air back through the color cup, "backwashing" the airbrush. doing this a couple of times while cleaning really helps to get all of the paint out of there!)
 

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Check that your Teflon packing retaining nut is tight and that the needle is scrupulously clean. The needle should be tight in the packing. There must be no paint or damage to the conical mating surface between the tip and the shell. Check the tip for splitting from incorrect assembly, you may need a magnifier (this is more of a problem with the single action air brushes though).
 

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It is probably the nozzle that is plugged. I have found that to happen on my Iwata gravity feed somewhat frequently. Cleaning the nozzle is difficult. Lately I have been using Windsor and Newton brush cleaner which I bought at Michael's in a big bottle for about $20. I did get a second bottle with a Michael's coupon for half that price. Anyway, I take the brush apart and remove the nozzle and nozzle covers. I put them in a small bottle with the brush cleaner and let it soak. Finally after soaking a bit I use one of those small plastic brushes with the felt tip and clean the inside of the nozzle. The last step is to take the needle and push out any residue in the tiny tip of the nozzle as well.

Lately I have been having fairly good luck with putting a few drops of the brush cleaner in the cup after shooting a color. I use the plastic felt tip brush to scrub the bottom of the cup and spray the excess out the nozzle. This is definitely helping to cut down on the requirement to disassemble so often. And then I drop a couple of drops of Freestyle cleaner in the cup and leave it there until I get ready to use the brush again.
 

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Actually, I was preparing to spray Future (which I have done successfully several times before).

Thanks, Starseeker. I will break it down again and see what I can find.
Don't know if you're doing this already or not, but before spraying Future (or any acrylic paint for that matter), spray a little Windex through the brush first, blow it dry, and then immediately after being done spray a couple of tablespoons more, making sure you "backblow" some as described above. Then repeat the process with water. It's important to clean it immediately after being done, every time, and at the highest PSI setting.

I don't think anyone else touched on this, another thing you should do is keep the needle lubricated (I use Superlube). This more than anything will prevent tip dry, probably the most common cause of irregular spraying and clogging. I lube mine every couple of sessions.

As mentioned, be very sure you DO NOT soak anything that's not metal in the airbrush in lacquer thinner. I'm fairly sure the Paasche VLS doesn't have teflon parts (check the specs on Paasche's website or the manual if unsure)...teflon resists degradation by solvents, one of the main reasons I got an Iwata Eclipse CS. Even so, teflon is solvent resistant, not solvent proof...continued soaking in lacquer thinner will damage teflon parts over time.

I made this mistake with my Iwata that has a rubber(?) o-ring in the piston assembly (that I thought was teflon) and it swelled up and caused "trigger stick", requiring a replacement ($6 for a tiny little rubber ring).

Although opinions vary, it's really not necessary (or advisable) to use lacquer thinner to clear out the brush after every session, unless you're using solvent-based paint (that from the folks over at Coast Airbrush). Windex works great for cleaning after using acryls. If you have to use lacquer thinner, wear a respirator and make sure you have adequate ventilation.

I have a VL too, and I rarely use it anymore since I got the Iwata...much better airbrush, easier to use, and cleanup is simpler.
 

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Halcyon,
You know that you can replace the rubber O ring with a Teflon one, right? I had an older Eclipse (the newer ones have Teflon) and replaced the O ring. Haven't had a problem with trigger stick since then.

Rob
Iwata Padawan
 

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Halcyon,
You know that you can replace the rubber O ring with a Teflon one, right? I had an older Eclipse (the newer ones have Teflon) and replaced the O ring. Haven't had a problem with trigger stick since then.

Rob
Iwata Padawan
No I didn't! When I had this problem, I called the guys at Coast Airbrush and they never mentioned that.

Are you sure you aren't talking about the needle packing set? All the Eclipses come with the teflon version from the factory now, but like you said the older ones didn't. The O-ring I'm referring to is the packing valve piston O-ring that the trigger sits on...some of the lacquer thinner got down there and swelled that sucker up like an inner tube.
 

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Ah... gotcha. Yep, that's still rubber since only air should be passing through there. Also, there's a sleeve in the valve section that can be removed and cleaned.

Rob
Iwata Padawan
 

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I have the Paasche VLS too. I use regular old paint thinner (mineral spirits) for cleaning up after using enamels and windex/water for acrylics. Don't use lacquer much except for clear overcoats which come in a rattle can and the few times I've sprayed metalizers. It does say in the instructions not to leave the airbrush body soaking in lacquer thinner for long as it degrades the rubber packing nut and O-ring in the valve seat. One thing I also like to do during cleanup (I disassemble and clean my airbrush after every session) is to blow canned air thru the housing and the tip. It usually gets any remaining paint residue out. That's after running a pipe cleaner thru the barrel. Sometimes you can get fuzz from the pipecleaner stuck inside the barrel but the canned air usually blows that out. Hold the barrel with the tip installed up to a light prior to reinserting the needle and trigger assemblyy. If you see a round lit circle you know you're clean.
 

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Sometimes you can get fuzz from the pipecleaner stuck inside the barrel but the canned air usually blows that out. Hold the barrel with the tip installed up to a light prior to reinserting the needle and trigger assemblyy. If you see a round lit circle you know you're clean.
I got a cleaning kit from Coast Airbrush that has cleaning brushes of various sizes to get into those hard to reach places, and they don't leave behind anything that could potentially clog it, like a pipe cleaner or q-tip. Most of the brushes seem designed for larger commerical paint guns, but the little ones are perfect for airbrushes. Despite my best efforts, I've found I have to disassemble the thing once in a while to totally clean out built-up residue.
 

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Ah... gotcha. Yep, that's still rubber since only air should be passing through there. Also, there's a sleeve in the valve section that can be removed and cleaned.

Rob
Iwata Padawan
Yeah...you have to remove that to get to the o-ring. The o-ring can get fouled when you pull out the needle while there are still contents in the cup...which is what I did (stupidly), since whatever you're spraying can then flow down into the trigger/piston parts, causing a serious PIA. :freak:
 

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Discussion Starter #16
Solution found

I've been working 12+ hour days this week so I couldn't get around to working on my airbrush problem till this morning. I broke the whole thing down and, even though it looked clean as a whistle, I cleaned it up a bit more (or went through the motions, anyway) and put it back together. There was no change in its operation--still blowing bubbles.

It wasn't until I started playing around with how far the needle adjusting sleeve was screwed in till I got some results. I found a small range that I could screw that part in/out where it would feed correctly. Problem solved.

As I've said before, I am a novice. Apparently the needle adjusting sleeve is used to adjust the flow of paint...? Odd that you have to have the airbrush partly disassembled to get to it.
 

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Let the nozzle soak overnight in what ever cleaning solution you're using.
I had this same problem about a month ago and after soaking the nozzle in rubbing alchohal I took mine apart and cleaned it but when I put it back together and ran paint through it the air bubbles were still there so I just put my finger over the tip of the nozzle and 'hit' the trigger. Problem solved.
The airbrush I got is an aztek double action, if that helps any.
 

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I don't think anyone else touched on this, another thing you should do is keep the needle lubricated (I use Superlube). This more than anything will prevent tip dry, probably the most common cause of irregular spraying and clogging. I lube mine every couple of sessions.
What brand Superlube are you using for the tip? Clogging tip is always a problem.........Iwata makes a Superlube but it doesn't mention using it for the tip. Do you have a link to the one you use? Thanks!!!
 
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