SOTAR 20/20 Speckling Help

Greetings all! I have a SOTAR 20/20 I use for miniature painting; I've had it for almost two years now, but haven't used it all that much; once every couple months probably. Whenever I do use it, the paint builds up at the tip so when I initiate a spray, there's a tiny burst of spattery paint that blasts out. Also, when spraying, there is a lot of speckling (extra dots of paint spraying beyond the normal spray zone if that makes sense).

I am using the fine needle with the fine nozzle. I normally have a ratio of 1:1 acrylic paint and flow improver, sometimes an extra drop or two of flow improver to thin it a little more. To attempt to slowly build up the color I normally spray between 5 and 10 psi.

I hope that covers more of the necessary details, but if I left anything and you need more clarification, please let me know. Any thoughts and suggestions would be greatly appreciated. Thanks in advance for your time!

sounds to me your PSI is to low try a higher PSI and paint building up at the tip is pretty normal that is why I always do a test spray on some paper before I start airbrushing

Hi jon, Tip dry is normal with airbrushing, Speckling is usually an indication of paint too thick OR not enough PSI. I had a Sotar and it didn't like paint that was too thick, so you could try thinning your paint a little and maybe upmthe pressure a little, it should stop the speckles when you get it right,

Lee

Oh cool, Jord and Ronald, good tips. I'll try to tweak what I normally do a little bit and see what works.

Also, to clarify, the paint doesn't dry at the tip. It seems each time I spray, wet paint still hangs around the tip, so the next time I spray, it blasts that wet paint with an uncontrollable splatter, if that makes sense. So I must wipe the tip off very frequently to I don't get that excess blast of splatter each time I spray. Or I initiate my spray to the side and then bring my brush in line with my model.

Jon said:

Oh cool, Jord and Ronald, good tips. I'll try to tweak what I normally do a little bit and see what works.

Also, to clarify, the paint doesn't dry at the tip. It seems each time I spray, wet paint still hangs around the tip, so the next time I spray, it blasts that wet paint with an uncontrollable splatter, if that makes sense. So I must wipe the tip off very frequently to I don't get that excess blast of splatter each time I spray. Or I initiate my spray to the side and then bring my brush in line with my model.

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What you describe may be an issue with not keeping the air on. Its very important to keep the air on well past the spray. And if you are cutting air off after each pass that will do exactly what you are describing. Hope thats helpful

I get this same thing from a couple of my Sotar's. I have just found ways to work around. If I paint, say a line, I get a wad of paint at the end (when I close the needle). If I start air flow again to paint another line, I get a wad as soon as I initiate air flow, followed by a gap until I draw the needle back... there are a few other brushes I see this from, but for sure the Sotar.

What I do is initiate air flow off to the side, and then move the brush into position before beginning paint flow. Wherever possible I continue paint flow until I am off the subject, and into a spot that I can cover later to deal with the inevitable wad at the end of the stroke. The other thing to look out for with these, are the two prongs if you are using that regulator cap. Even at medium openings, paint will build up on the prongs, and spit the next time you initiate air flow. Wipe them often.

Nice tip Dave, I only used mine a few times before I gifted it to a friend who wanted one, So didn't have it in use much.

Lee

I used to get a blob or spurt of paint when shutting paint off. (needle forward air still on) . As soon as I reduce (thin) the paint more, it would stop.
If you are getting a spurt of paint when starting to draw back for paint, then you shut down your air too soon after stopping paint flow. Always keep this in the back of your mind....Air on, paint on...paint off, air off...

DaveG said:

I get this same thing from a couple of my Sotar's. I have just found ways to work around. If I paint, say a line, I get a wad of paint at the end (when I close the needle). If I start air flow again to paint another line, I get a wad as soon as I initiate air flow, followed by a gap until I draw the needle back... there are a few other brushes I see this from, but for sure the Sotar.

What I do is initiate air flow off to the side, and then move the brush into position before beginning paint flow. Wherever possible I continue paint flow until I am off the subject, and into a spot that I can cover later to deal with the inevitable wad at the end of the stroke. The other thing to look out for with these, are the two prongs if you are using that regulator cap. Even at medium openings, paint will build up on the prongs, and spit the next time you initiate air flow. Wipe them often.

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Oh perfect, Dave, thanks for the insight! I'm glad I'm not the only having that issue with this particular airbrush. I thought maybe I was doing something wrong or had got a lemon or something, . Thanks for the advice, appreciate it!

The speckling in the pattern is also something that I notice. I get a nice, fine atomization, mixed with a coarser, random speckling mixed in. The brush will typically still produce very fine details, so I just accept it is part of the package. You can trust that I have tried everything to remedy these conditions...

DaveG said:

The speckling in the pattern is also something that I notice. I get a nice, fine atomization, mixed with a coarser, random speckling mixed in. The brush will typically still produce very fine details, so I just accept it is part of the package. You can trust that I have tried everything to remedy these conditions...

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If Dave can't cure it 100% then thats how it is.

DaveG said:

The speckling in the pattern is also something that I notice. I get a nice, fine atomization, mixed with a coarser, random speckling mixed in. The brush will typically still produce very fine details, so I just accept it is part of the package. You can trust that I have tried everything to remedy these conditions...

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Is there another airbrush that you might recommend for up-close, detail work?

Jon said:

Is there another airbrush that you might recommend for up-close, detail work?

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There are lot of really good brushes. Even the Sotar - you could try changing parts, which will most likely be the least expensive way to experiment. New nozzle, needle, and regulator cap - may just do the job. I do get mixed results with them... I was actually just in my studio working on a couple of Sotar's

That being said, there are a bunch of really good brushes out there. A lot will depend on the budget you have in mind. One of the best bang for the buck values out there at the moment is a Creos GSI PS270 in .2, or a PS289 in .3, at just over $100. Fantastic quality, and performance. The only drawback to these is the physical size, as they are larger brushes to hold - they do balance very well in hand, though.

My SOTAR is my best brush for mini painting, as the shape of the (non-pronged) air cap gives the needle the most side clearance when up close to a complex 3D surface. I can get in and around tight nooks and crannies better with the SOTAR than with my Micron or Eclipse. Not relevant for priming or base colors, but for freehand shading and detail it makes a difference.

I have had a bit of weirdness with nozzles though. I have two "fine" nozzles for it, and they behave VERY differently. One works perfectly (paired with the "fine" needle and air cap), the other tends to clog easily, has "late start" issues when pulling back the trigger, produces less consistent atomization, and is WAY pickier about reduction.

I compared the two under magnification, and the bad one is slightly longer with a smaller hole at the tip. I find myself wondering if the good nozzle is actually a "medium" nozzle that was accidentally put in at the factory (it's what came with the "fine" kit version of the brush).

If anyone else has a SOTAR with both fine and medium kit, I'd love to hear if this can be verified. I'm a bit worried about unpredictability/inconsistency if/when I ever have to replace the nozzle on mine.

If the good nozzle is indeed a "medium" nozzle, that would be an interesting and useful discovery. It shouldn't spray better with a mismatched nozzle, but if it is the case, it might also be relevant to the problems Jon and Dave are describing.

There is really a significant difference between the fine and medium nozzles, even without magnification.

These are all fresh - a combination of the Sotar and Renegade nozzles. While they do use different names for each model, the different sizes appear to be the same physical pieces with different part numbers (Fine in Sotar = Ultra Fine in Renegade, Medium Sotar = Fine Renegade). I measured them with precision gauge pins to get a reading on the actual size of the exit bore. Black numbers are advertised, or listed. Orange numbers physical measurements.



I also measured a batch of "fine" nozzles and found several different sizes within a single batch of part numbers. It comes down to about the width of a piece of human hair between them. When I tried the same amount of Japanese nozzles, I found they all fit only one pin size.



Did the same sort of thing with the regulator caps on the Sotar/Renegade brushes, and found the same sort of range of sizes. This is probably within their specified range of tolerances. In manufacturing terms, it is a small +/- range. It is however a greater +/- range than I have measured in other brands (that is 5 Iwata caps that only fit one size gauge pin - pins are accurate to within 0.0002")



What it means is that any given set of parts could potentially vary in fit, and performance from one brush to another in fairly obvious ways. It is why I suggested perhaps trying a new set of parts before looking for another brush.