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airbrush issue: alot a air but no paint

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Discussion starter · #21 ·
Greg Elmassian said:
So it was not completely clean from what you are saying. Well, sometimes experience is the best teacher.

Also, I learned something, test with water, higher viscosity, clearly mineral spirits working did not point out your problem (because it did not properly simulate paint's viscosity).

The water test is simple, and not messy. I gather you want to be sure to get all moisture dried out before using paint.

Greg
Click to expand...
I am still learning the process; I think the orifice might have been clogged, but again not very sure of anything; everything is still in the experimental curve for me. I will have to learn how to clean the device carefully after each use and the moisture issue as you mentioned also crucial to ensure appropriate paint spray.
 
Discussion starter · #22 ·
tmejia said:
Great to hear you got it working again.:D

Just keep track if you alternate between spraying lacquer, enamels or acrylics. They use different thinners and cleaners.
I always thin my acrylic paints before spraying and I always use an airbrush cleaner after I am done spraying.

Here is a link to a video by Red Dragon ModelWerks if you wish to make your own cleaner.

https://youtu.be/HY5mr5gLHRY


Have fun spraying.

Tommy:cool:
Rio Gracie
Click to expand...
Thanks for the movie, I will learn to prepare cleaning solution from that movie.
 
#24 ·
Perhaps that is the key, the solvent used for cleaning initially was not agressive enough, or allowed to soak long enough.

Isn't the rule of thumb is the solvent used to clean needs to be "hotter" than the solvent in the paint?

Greg
 
#25 ·
Greg Elmassian said:
Isn't the rule of thumb is the solvent used to clean needs to be "hotter" than the solvent in the paint?
Click to expand...
Don't know anything about that, but I've yet to see any paint (short of epoxy paints) that will stand up to acetone. Also, a single action makes it so much easier as only two parts (exempting the color bottle) are actually exposed to paint and subject to clogging - the needle and the cone - and both are easily removable and cleanable (i.e. easily soaked). I started with a single action Binks some 50 years ago, always got the results I was after, and stuck with that type due to it's simplicity of construction, operation, and maintenance - the KISS principle. ;) Additionally, replacement cones and needles are cheap and readily available if needed (say you drop it).
 
#26 ·
It also depends on what you are using your airbrush to accomplish and what media you are spraying.

I have 5 different double action airbrushes. I just received the fifth one and will be trying it out in the next few days.

I work with 1/20.3, 1/24, 1/29, 1/35, 1/48 and 1/350.

If you are using your airbrush to just paint in lieu of spray cans you can be more aggressive in your cleaning. Problems arise when aggressive cleaners, like acetone used regularly and for extended periods of time wear away the seals in older airbrushes.

Fortunately, newer airbrushes have teflon seals.

I try to use the least aggressive cleaner in my airbrushes.
If I am shooting Stynlrez primer (acrylic polyurethane), all I use is water to clean the airbrush.

I spray acrylics 95% of the time. Still looking for a good 1 part acrylic UV matte/flat finish clear coat.

What I am trying to say is there is not one way of doing it or one magical product that will do everything.

The more you practice, spray and clean your airbrush the more you learn.

Have fun spraying:).

Tommy:cool:
Rio Gracie
 
Discussion starter · #27 ·
mymodeltrain said:
I wonder if someone has experience with airbrush so I learn from. Basically, I have an Iwata pressure system with the Neo airbrush used for Iwata. It works well in the first week, but now it didn't work anymore. A lot of air came out but very little or no paint. I used maximal pressure, the same outcome happened. I used Testors airbrush paint. Then I clean everything to ensure no blockade but it didn't help.
I noted that if I use water or alcohol not much spray coming out but when I switched to mineral pirits, alot of spray came out, perfectly. I wish to mix paint with mineral pirits but the problem is that they are not mixable.
Click to expand...


Thank you all for sharing experience on how to use airbrush and related matters. Particularly, thinning the paint is one of the key components in this process. I want to share my experience as I learned and tested what really works for me in the past few days.
Basically, I found out that I don't need to use Testors acrylic paint, but I can use Americana acrylic paint, which is 3 times cheaper for the same amount. Different people suggest to use different materials like water or windshield liquids as thinner solution. Based the chemical structure of acrylic polymer, I would rank the best thinner for acrylic paint as ethanol > isopropanol > water to bring the paint into homogenous solution. If the paint solubilizes in solution easily, it means that we don't need to spend extra effort for vigorous stirring. Last night, I mixed 6:4 of Americana acrylic paint:isopropanol and I used a wood stick to stir the mixture for a few seconds; the spray was so great. I sprayed a lot but no cloggage happened. The advantage of using isopropanol compared to water is that it dries much faster, albeit the viscosity is high (isopropanol is twice more viscous than water). As I rank ethanol the best since it will bring acrylic paint to solution not only very easy but it is also less viscous compared to water; I expect this mixture will not clog the airbrush. But overall, I am satisfied with isopropanol result. I am certain the windshield liquid will provide similar result (even not try yet) since the solution has a mixture of ethanol/ methanol along with glycol and isopropanol. However, you have to make sure NO methanol in the liquid since absorption of methanol in the body will resulted in damaging optic nerves, which may lead to blindness. As far as I know, industry nowadays tries to replace methanol for ethanol; a quick check is crucial for your health in the long term.
 
Discussion starter · #29 ·
Greg Elmassian said:
The viscosity of isopropanol (rubbing alcohol) is 1.77cp @ 30C. Water is 0.80cp @ 30C.

Close, but ISP is less viscous than water... (flows more freely than water).

Greg
Click to expand...
Thanks Greg for the information to improve our knowledge regarding the preparation of better painting solution; I am certain that isopropanol is more viscous than water but the surface tension and density of isopropanol is much less than water. I didn't think about that in the last message that the flow is probably dependent on these 3 properties, not on the viscosity alone, overall may give isopropanol a bit advantage.
 
#30 ·
Sorry, centipoise is the measurement unit "cp", but the number means how much fluid flows in a given time period... (and it's a dynamic unit of measure)

So ISP at 1.77 flows more than twice as fast as water at 0.8 ....

Viscosity is thickness, so we speak of a thicker, slower flowing liquid as more viscous.

So, water is more "viscous" than ISP, i.e. it is "thicker"... that is also why trying water in the brush is a better test than trying "spirits".

But unfortunately the measurement of viscosity is sort of backwards in the poise / centipoise measurements (don't blame me for this mess!)

So from common language water is more viscous than ISP, and density does not always map directly to density.

So a higher cp number means thinner, flows more easily, actually less viscous.

So bottom line, if you have a brush that is not flowing right, it COULD work with ISP but not with water... again why water is a good test.

We started back where you tried mineral spirits and they worked fine but not your acrylic paint... all that makes sense when you look at the viscosity of the liquids you used.

Greg
 
Discussion starter · #31 ·
Greg Elmassian said:
Sorry, centipoise is the measurement unit "cp", but the number means how much fluid flows in a given time period... (and it's a dynamic unit of measure)

So ISP at 1.77 flows more than twice as fast as water at 0.8 ....

Viscosity is thickness, so we speak of a thicker, slower flowing liquid as more viscous.

So, water is more "viscous" than ISP, i.e. it is "thicker"... that is also why trying water in the brush is a better test than trying "spirits".

But unfortunately the measurement of viscosity is sort of backwards in the poise / centipoise measurements (don't blame me for this mess!)

So from common language water is more viscous than ISP, and density does not always map directly to density.

So a higher cp number means thinner, flows more easily, actually less viscous.

So bottom line, if you have a brush that is not flowing right, it COULD work with ISP but not with water... again why water is a good test.

We started back where you tried mineral spirits and they worked fine but not your acrylic paint... all that makes sense when you look at the viscosity of the liquids you used.

Greg
Click to expand...
Viscosity describes the internal friction of a moving fluid. And cP is a unit of viscosity; a fluid with large viscosity resists motion because its molecular makeup gives it a lot of internal friction. A fluid with low viscosity flows easily because its molecular makeup results in very little friction when it is in motion.

If you look at this table from this link, http://www.cstsales.com/viscosity.html
it suggests that the higher cP values the more viscous the solution is; and thus it has slow flow.
 
Discussion starter · #32 ·
mymodeltrain said:
Viscosity describes the internal friction of a moving fluid. And cP is a unit of viscosity; a fluid with large viscosity resists motion because its molecular makeup gives it a lot of internal friction. A fluid with low viscosity flows easily because its molecular makeup results in very little friction when it is in motion.

If you look at this table from this link, http://www.cstsales.com/viscosity.html
it suggests that the higher cP values the more viscous the solution is; and thus it has slow flow.
Click to expand...


I want to share some good experiences I got in the past few days. For the Neo airbrush, usually, I always assume the needle should be pushed all the way up until the its tip protrudes from the orifice. But in that position, the spray didn't come out nicely, usually narrow and some cloggage if the paint is slightly thick; and the pressure I used is high ~ 30 psi. I found out the way to go around is to pull the need back a bit, until none can be seen from the orifice, in that position, the spray is large, uniform and the airbrush did not clog. Further, I can tune down the pressure to approximately 10-15 psi. So after spending many weeks with trial-and-error, I think I am very comfortable with airbrush now, more exciting work is coming. Thanks all for your kind help.
 
#33 ·
I am glad you found a way to spray that works for YOU.:)

BUT

If you are pulling the needle back and not seating it all the way into the orifice to spray you are
not using the airbrush the way it was designed.

Either you are not thinning your paint enough for the size needle you are using
or
your needle is not adjusted correctly
or
Your air pressure needs to be adjusted
or
you need to go to a larger needle setup.

Basically you are bypassing the fine control you can achieve with an airbrush.
Once you change paints that are thinner, your airbrush will be spitting out paint without you pulling on the trigger.

Acrylics do spray differently than enamels or lacquers. Dry tip clogs are a known to occur with acrylics but a simple careful wipe of the tip with a paper towel takes care of that. Also some acrylic thinners contain retarders that help with tip drying.

It all comes back to what is it you are trying to accomplish with your airbrush. Are you just trying to lay down an even coat over a large area or are you trying to control the spray pattern to detail a specific area?

At the end of the day what matters the most is - Did it work for you? Are you having fun spraying and enjoying the results?

I thoroughly enjoy airbrushing and only use rattle cans when I have no choice (Like UV Clear coats. I am still looking for a 1 part UV Flat,Matte Acrylic clear coat to run through my airbrush)

Keep on spraying.;)

Tommy:cool:
Rio Gracie

PS: Can we get some pictures?

 
#34 ·
Back in my college daze, we use an old, ladies nylon stocking, to strain the thinned paint before it got near the air brush.
Sounds to me, like a thick mix...

John
 
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Discussion starter · #35 ·
tmejia said:
I am glad you found a way to spray that works for YOU.:)

BUT

If you are pulling the needle back and not seating it all the way into the orifice to spray you are
not using the airbrush the way it was designed.

Either you are not thinning your paint enough for the size needle you are using
or
your needle is not adjusted correctly
or
Your air pressure needs to be adjusted
or
you need to go to a larger needle setup.

Basically you are bypassing the fine control you can achieve with an airbrush.
Once you change paints that are thinner, your airbrush will be spitting out paint without you pulling on the trigger.

Acrylics do spray differently than enamels or lacquers. Dry tip clogs are a known to occur with acrylics but a simple careful wipe of the tip with a paper towel takes care of that. Also some acrylic thinners contain retarders that help with tip drying.

It all comes back to what is it you are trying to accomplish with your airbrush. Are you just trying to lay down an even coat over a large area or are you trying to control the spray pattern to detail a specific area?

At the end of the day what matters the most is - Did it work for you? Are you having fun spraying and enjoying the results?

I thoroughly enjoy airbrushing and only use rattle cans when I have no choice (Like UV Clear coats. I am still looking for a 1 part UV Flat,Matte Acrylic clear coat to run through my airbrush)

Keep on spraying.;)

Tommy:cool:
Rio Gracie

PS: Can we get some pictures?
Click to expand...

I don't know the size of my needle; I need to do some more research on that, either 0.35 or 0.5 mm. But you are right I use airbrush for painting large surface area and thus the setting I used is OK for me. But I imagine, if you paint a small and more dedicated area, probably, it won't work. Everything is still a learning curve for me. I will keep learning. You can see the thread of the modified building I listed yesterday that I used airbrush and a brick stencil to make brick walls.
 
#36 ·
David Leech said:
I am not familiar with your airbrush, but have been using my Badger for some 20 years.
What is interesting is that yours WAS fine for the first week, and then isn't after that.
What has changed?
I found early on that it is so critical that after you disassemble it to clean everything REALLY WELL, that you make sure that you put it back together correctly.
Something simple as not tightening something properly, or forgetting to put a washer in the correct place, or finding that something is slightly damaged, can disturb the function of the airbrush.
I use an eyeglass to check how clean everything is before reassembly as my airbrush does not work well with just the slightest piece of dirt, or dried paint, where it shouldn't be.
Go back to basics - after cleaning and reassembling, test again with mineral spirits, or lacquer thinner and check the spray pattern.
If it looks good, then there is nothing now wrong with the airbrush itself.
So, if now your paint isn't working, it's to do with paint or the mixture.
How do you stir the paint?
I use a tool in my drill press for 60 seconds to make sure that the paint is fully stirred.
Waving a screwdriver around, or just shaking is normally not good enough.
If there are bits in the paint, they must NOT get into the airbrush, so strain them out.
You will just have to experiment with the amount of thinner and air pressure to find what works for that paint and that colour.
I have found differences in mixture and pressure between paints and colours.
I hope that helps.
Don't give up, and keep trying.
It probably took me 6 months before I really felt that I understood my airbrush, and how to use it, and most of all felt comfortable and relaxed overtime I went into my paint booth.
Cheers,
David Leech, Delta, Canada
Click to expand...
Hello. I've been at it for three hours and am ready to break the damn thing with my bare hands. I've run it through my ultra sonic cleaner a dozen times, ran pipe cleaner through the barrel, used acetone to clear out the inside of the nozzle, NOTHING has worked. I'm getting air but no paint out of the air brush. I put in a new needle and still get nothing coming out. ANY suggestions would be fantastic. I use a Badger Renegade Krome with an Aspire TC-908 compressor, at 10 PSI.
 
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