Airbrushing acrylics--HELP!!

Not sure what I'm doing wrong, but.... I have a Paashe VL, trying to spray
various acrylics with zero luck. I've tried Tamiya, Pactra and Testors, and
consistently get the same results--spitting, splatters and beading. The
spitting and splatters I could normally attribute to thinning or air pressure,
but I've adjusted both up and down to no avail (latest attempt was 2:1
paint/thinner and 10 PSI). Initially I was using the #1 tip/nozzle in the
airbrush to keep the spray pattern small, had all the above problems, so I went
to the #3 tip/nozzle, no change. As I thin the paint more, the beading becomes
worse, and if I thin less, it spits and splatters. Now FWIW, I'm spraying onto
washed and dry but unprimed surfaces--is that the problem? If so, what do I
use for primer, and how do I not get buildup and lose surface detail? I've
never seen Mr Surfacer in the local shops, so is there something else? I don't
have these problems to this degree using solvent-based paint, so I can't blame
it all on lack of talent/experience, although it's most definitely a factor.
Also, the VL is my first and only airbrush to this point--a different one is
not out of the question, so if anyone may have something they want to swap, I'm
game. Painting full size stuff is so much simpler.
When once you have tasted flight, you will forever walk the earth with your
eyes turned skyward, for there you have been, and there you will always long to
return. --Leonardo Da Vinci
Reply to
Disco -- FlyNavy
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snipped-for-privacy@aol.com.mil.nav (Disco -- FlyNavy) schrieb:
What kind of "thinner" u are useing???
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Bluemax
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Reply to
Bluemax
I use a VL with acrylics (Polly Scale and Tamiya) all the time. Getting it right can be tedious. Consider the following:
1. The VL must be very clean, especially needle and nozzle assembly. Acrylics will accumulate there during the spray process, though I rarely have to worry about that until it's time to change colors. Clean after every color change--with practice, this will only take five minutes or so, and need not include removing the trigger (although that should be done at the end of session or if the brush is balky--with practice, the trigger can be reinstalled in just a minute or so). 2. It's hard to thin too much. With Tamiya in particular,I've been thinnning with isopropanol (70% concentration) in a 1:1 ratio with paint, and sometimes a little more thinner than paint. This will dry very quickly, given the alcohol content, so it's possible to add another mist coat every 15 seconds or so, which compensates for the relatively low pigment density from so much thinning. With Polly Scale, I only thin with the proprietary thinner (which evidently formulates to 10% isopropanol, 25% blue antifreeze (glycol), 65% distilled water if you want to mix your own), using slightly more paint than thinner, and using the same technique of many thin coats in rapid succession. 3. Start the spray pass off the model and end off the model, where possible. Spitting, when it occurs, seems to be an issue when I first depress the trigger, and maybe at the end of the the spray run. If you get spitting onto the model, having a brush at hand to remove or blend it works sometimes. 4. I use relatively high pressure (20-25 psi) because I want the paint fully atomized--I believe spitting is more likely where the pressure is insufficient to completely vaporize the paint. My knowledge of physics is pretty pathetic, though, so maybe I've just been lucky. 5. I don't prime anything before using acrylics. If you get the mold release off, that's probably half the battle to good adhesion. I've only had two models in the last five years where the acrylics did not stick adequately to the plastic, and I think mold release agents were the problem both times. One thing I will do with Tamiya is base coat with white before using their yellow or red, because the white is really opaque, but the red and yellow are pretty translucent. 6. I've never tried anything except the #1 needle/tip. 7. The one time I tried Testors Acryl, I got spitting no matter what I tried. I may not have been using the right thinner.
Mark Schynert
Reply to
Mark Schynert
I also had zilch success airbrushing with acrylics, until I asked the local hobby store guy about it. He recommended, and sold me, a bottle of Polly S Airbrush Thinner #556008.
It works great! For all I know it's just windshield washer fluid, but what the heck.
DLF
Reply to
David Ferris
hobby store guy about it. He recommended, and sold me, a bottle of Polly S Airbrush Thinner #556008--It works great! For all I know it's just windshield washer fluid, but what the heck.>>
To all who replied--thank you, I appreciate the efforts. The thinner I use is the one thing I did indeed forget to mention. I've tried Isopropyl alcohol, windshield solvent, and straight water (tap and distilled); same results all around. One thing I haven't tried is "airbrush thinner", simply because I'm one of the ultimate tightwads (one of my nicknames is Scrooge--it's true, trust me!), and after doing a sniff test came to the conclusion it's just one form of alcohol or another, so why spend the extra money? Same reason I don't buy the various decal solvents; one is weak vinegar, the alcohol). However, this may change in an effort to actually accomplish the task at hand. Also, although it's a scary proposition, I'll try running the pressure up to 20-25 PSI and see what happens. If all else fails, I do have a local airbrush artist somewhat at my disposal, and for a paltry $75 she will guide me through the evil forest to the Emerald City where, at last, I may find a brain!
When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return. --Leonardo Da Vinci
Reply to
Disco -- FlyNavy
Lemme hear this again, too cheap to buy the airbrush thinner for 5 or 10 but you'll pay someone $75 to show you what you're doing wrong?
If the advice this group give you doesn't help (I don't see why it wouldn't!) go to your local art store and get some acrylic retarder and ask them what's wrong. You also might buy the proprietary thinners and experiment in combinations, writing down your results. $75 buys a lot of thinner and paint! Pretend you're a scientist! That's what I did! Whenever I spray with acrylics I use methanol and haven't had a problem. hth
The Keeper (of too much crap)
Reply to
Keeper
I have always used Tamiya thinners and have not had any problems (and I haven't used an airbrush for years and years until recently). I mentioned to my hobby shop that I was spraying acrylics and was going to use water. they promptly disabused me of this idea and sold me some of the Tamiya stuff which seems to work perfectly. I sprap Polly Scale, Tamiya and LifeColor.
David
Reply to
David Pennington
you'll pay someone $75 to show you what you're doing wrong?>>
Yes, because there is a method to that madness. Buying proprietary thinner and experimenting doesn't necessarily guarantee results, as the problem could lie in technique or pressure settings, which this experiment would never reveal. Whereas gleaning legitimate instruction from an airbrush artist would eliminate that variable. Since I already use the same thinners that the majority use, empirical data and the laws of probabilities states that variable has all but eliminated itself. Given that, I have taken to do some experimenting, using the advice given regarding thinning (with windshield solvent/alcohol) and pressure, and have achieved much better results. There are still some things to try, but I'm headed in the right direction. I'm still trying to figure out the fine line spraying, but the high pressures and current thinning ratio won't allow it, although large area painting is working well. So, it's back to the lab for a few more tests. Again, thank you very much to all who replied.
When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return. --Leonardo Da Vinci
Reply to
Disco -- FlyNavy
The Paasche tips have very little space between the bore and the needle and sometimes paint, particularly when not properly thinned, can clog there and obstruct the paint flow, which gives symptoms similar to what you have. Make sure that the tip is perfectly clean outside _and_ inside.
Beading usually means one or several of four things : - too much thinner - air pressure too high - airbrush too close to the surface - the combination of paint/thinner does not wet the surface
Reply to
[SM04]Serge D. Grun
Still $75 bucks worth ??? Geeze, buy the goddammed thinner !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
If you folllow what Mark wrote in his post, than you should never have any problems.
For fine lines can you say HVLP ?? (high volume low pressure) Thin the paint to like 70:30, or even 80:20 and then crank the pressure down to 15 psi. Takes some practice, but even with my cheap Aztec ab, I can get very thin lines, You can also try high pressure low volume, but be prepared for some overspray if your not very carefull.
Also you might want to see what the temp, and dew points are. When within 10 degrees of each other, it is not a good idea to be airbrushing, as ice can and will form at the nozzle destroying the spray pattern.
"Only a Gentleman can insult me, and a true Gentleman never will..."
Reply to
Azzz1588

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