Air Brushing - Starting points

[inobu]

He is an example of a MiJack airbrushed machine yellow. The model was orange plastic.

More details...

As you can see the detail of the door handle is still visible, even the mesh screen is rendered (zoom in on image). The ability to maintain such detail is in the control of the volume of paint sprayed. There are factors that play into achieving this level of results. Now that we can see what an air brush can do, lets understand the basics.

Air brushes uses air to apply paint. The amount of paint delivered depends on the size of the brush or in this case the size of the needle, valve and tip. The needles and tips are banded 1,3 or 5 (Paasche). This is your size indicators.

More details...

When the paint is siphoned by the air through the airbrush it is atomized into a mist. The density of this mist depends on the opening of the tip and how much the needle is pulled back. The recommended dual action brush allows you to control the amount of air and paint. This gives you the control needed to create realistic clouds and sky lines on your back drop, fading in the blues and whites with touches of grays highlights the sky scene just as matt finishes on your building can look like concrete.

The viscosity of the paint is important. Thick paint with a small valve will do nothing by clog just as thin paint with a large valve will run and spit. You must maintain a balance in order to shoot a great finish.

Air supply has its contributing factor that proves to sway or deter people from using an air brushed. It is either the poor results or the excessive noise of the compressor that drive them crazy. Unfortunately the starter kits starts us off on the wrong foot. Although they are in the right price range it does not provide us with the air we need to shoot N-Scale modeling. The small compressors have diaphragms that creates pulses of air that can be seen on the finish. Because of these pulses the painter will try to correct the finish and end up applying multiple coats covering the small details or ruining the model.

The best compressors are the oil type with a few gallon air tanks. These are more so refrigerators motors, quiet and costly but well worth the money. There are issues where oil enters the air stream but traps are placed in line to remove the oil. Any compressor that can maintain 116 psi with an integrated tank should work. You want the tanks to maintain a steady air flow. Someone mentioned using and filling an air tank but the problem is the steady loss of air. This causes an uneven pattern. Eventually you will lose pressure and the brush will die off. It if dies at the wrong time it will spit on your work of art and ruin it.  

There is no cheap way around "Good" airbrushing and no better way of adding the finishing touches on your layout.  
        
Inobu
  
 

  
  


    

[quinntopia]

Inobu,  thanks for sharing this.  I've long struggled with airbrushing. 

Do you have any recommendations on paint brands?  I've tried to use the Polly Scale paints (a water based paint) but they don't seem to work all that well consistently (perhaps they go 'bad' after sitting for some time?) and have wondered if I should try another brand before giving up on air-brushing altogether.  The alternative would be to invest in a new compressor (I am using an old one right now that was hand-me-down from my father) that I suspect may also be the problem (to your point, I'm not entirely sure its generating the pressure it needs to get the paint through the nozzle, although it does fine with water!).

Any suggestions?

[Bernard]

Inobu - Thanks for the info and the nice results you got with your model. I have a question about the adjustment of air compressor. Is there a recommended setting range? I have an Iwata compressor with an adjustment knob:
http://www.dixieart.com/Iwata_Sprint_Jet_Air_Compressor.html

[Martijn Meerts]

Do you have any recommendations on paint brands?  I've tried to use the Polly Scale paints (a water based paint) but they don't seem to work all that well consistently (perhaps they go 'bad' after sitting for some time?) and have wondered if I should try another brand before giving up on air-brushing altogether. 

A lot of modelers use Gunze Sangyo paints, but they tend to be difficult to get. I've used Tamiya myself for pretty much everything when I switched from enamel to acrylics. I'm going to try some Gunze on my Gundam models, finally found a store that has the stuff in stock, so I don't have to try and import it ;)

[inobu]

quinntopia,

There's really not one brand of paint but more so the type.  There are acrylic, lacquer, enamels , water base, oil base the list goes on. Here is the most important point. Being that you can airbrush anything it is critical to choose a paint that will stick or adhere to the surface of the model best. I have mostly Tamiya and Createx because they are easy to get for me and it just a choice.

As for the compressor both you and Bernard are going through ABSS (Air Brush Starter Syndrome) I went through it too. We know and can see the great uses of the brush and go for that starter compressor.

My story

I got my compressor from a manicurist that complained the air brush setup did not work for nails. I bought it and realized that she was not thinning out the nail polish and clogging her needle. My ABSS hit me when I could not get a smooth finish and was ready to quit, fortunately for me I started to ask around and was told to get a better compressor and I saw the difference.

Here is the hidden truth about these starter compressor that we miss. CFM Cubic feet per minute.

Bernard I'll use your compressor data for example.

Features:
Zero maintenance oil-less piston air compressor
Powerful 1/8 hp motor
Moisture-filter also prevents pulsation
Mounted air pressure gauge
Bleed valve airflow adjustment to adjust air pressure
Working pressure from 1 psi to 35 psi
High strength polyurethane air hose fits all Iwata airbrushes
On/off switch

Air Flow: .64 CFM (18 lpm)
Weight: 8 LBS (3.8 kgs)
Size: 10 x 7 x 6 IN. (25 x 18 x 16 cm)
 

These smaller compressor numbers are max levels at 100% duty cycles which just is not enough for consistent spraying. You want to run 50 to 75% of you max. That formula just cuts the efficiency level down too much.

A tanked system can maintain about .7 CFM to 2 CFM, .5 to 3 gallons of air @ 80 psi at all times depending on the model. The number presented are about 50% duty cycle. This setup delivers a constant level of air to drive most types of paint.

Here is a good way to visualize it.

We all know DPI (Dots per inch). The higher the dpi the better the quality. In painting the atomization is the mixing of air and paint particles. These particles of air and paint creates the dots. The more air you can push the more dot you have therefore a higher DPI or finer mist of paint which we call a coat.  

There is just not enough variation or range in these smaller compressor to drive the atomization we need in N-scale.

Hope this helps and I encourage you to keep at it.

Inobu



      

[Martijn Meerts]

I have a cheap compressor and airbrush as well. It's not all that bad if you just want to spray larger portions with a single color. It's no good for detail stuff though, and the compressor doesn't like being turned on all that much.

I also don't have a water filter thingy, so I can't use the airbrush all that long without taking a break. I should get a filter, but I actually really just need a better compressor.

The airbrush itself is a dual action, and not all that bad. It doesn't have this nice feature that I've seen with some Iwata, where you can limit how far the needle can open up, so in effect you can regulate the maximum amount of paint. This is especially nice when doing shading.

I did get quite a decent, smooth coat of paint with my first attempt, but then again, I have spray painted cars before when I worked in a car workshop. So I had some experience, albeit on a slightly larger scale ;)

[quinntopia]

Thanks Inobu, that is encouraging!  I should have also mentioned that the compressor goes 'on' and 'off' in about a 10 second cycle, so I suspect the compressor is at fault.

[NozomiFan]

Do you have any recommendations on paint brands?  I've tried to use the Polly Scale paints (a water based paint) but they don't seem to work all that well consistently (perhaps they go 'bad' after sitting for some time?) and have wondered if I should try another brand before giving up on air-brushing altogether. 

A lot of modelers use Gunze Sangyo paints, but they tend to be difficult to get. I've used Tamiya myself for pretty much everything when I switched from enamel to acrylics. I'm going to try some Gunze on my Gundam models, finally found a store that has the stuff in stock, so I don't have to try and import it ;)

If you want to go Gunze Sangyo/GSI creos get the Aquarius Hobby Paint and not Mr. Color. Mr. Color is lacquer while Aquarius is acrylic.
Try Tamiya their stuff is great because you can get lacquer, enamel and acrylic all in the same place.
Also a word on Tamiya lacquer. USE A RESPIRATOR and wash off all plastic to be sprayed. (Wash off as in use a dish soap.)
Happy Spraying!

[Martijn Meerts]

Time for a bit of old thread resurrection ;)

Due to a positive financial surprise, I'll soon be able to replace my cheapo compressor and cheapo airbrush with something less cheapo. I'm not looking for anything professional, just for something that works well for model trains and model kit building in general.

I've talked a bit with the owner of a store that specializes in airbrushes (they also do lots of beginner/advanced courses and such at the store), and he figured for my use the following combination would be good.

Compressor: Euro-Tec 16A (http://www.harder-airbrush.de/english/kompressor_13.html)
Not all too noisy, decent sized tank, supposedly good quality, and also supposedly very servicable. Interesting is that it says 23 liters per minute on some sites, yet 16 liters per minute on other sites (I'm leaning towards it being 16 liters because of the 16A. Then again, the 20A seems to be 17 liters per minute...)

Airbrush: Harder & Steenbeck Infinity 2 in 1 (http://www.harder-airbrush.de/english/infinity_02.html)
Granted, this one is semi-professional and quite expensive, but it comes highly recommended. I like the fact that it can take multiple needle sizes and especially the quickfix system. Another advantage, it looks damn good for as far as an airbrush can look good ;)


Anyone have any comments about the combo?

[inobu]

You are going to be faced with the same issue in a few months. I don't think that unit will support your future needs as you get better. That particular unit looks like it is a diaphragm compressor with a tank. Air pressure and tank size play an important role in operating airbrushes effectively.

The tank needs to store enough air where the compressor doesn't run continuously. The tank size also creates a buffer that allows for air regulation. The target/regulated air pressure should be 50 to 60% of the maximum psi rating. When you apply these factors to the specified unit it's performance become questionable.

Cleaning the brush is critical when painting multiple colors and you need to run air/cleaner through the brush. This consumes a lot of air and will have the pump cycling a lot. The last thing you need is for the unit to overheat and shut off in the middle of a coat. You need at least 35 to 40 psi continuous to shoot a fine enough coat to cover the detail in N-Scale items. I don't think that unit can do that.

I would just wait for the next financial windfall to get a HTC 30A. After that you will not have to worry about a compressor again.
It's switches on at 90 psi and shuts off at 116 psi. You will never see the effects whenever you regulate below that 50% mark.

I have the Badger version of the HTC 30A from the mid 90's and it still runs perfectly. I know it is double the price but after all this would be your second compressor.

Inobu

[Bernard]

inobu - I miss this post where you used my compressor. Thanks!

[Martijn Meerts]

You are going to be faced with the same issue in a few months. I don't think that unit will support your future needs as you get better. That particular unit looks like it is a diaphragm compressor with a tank. Air pressure and tank size play an important role in operating airbrushes effectively.

The tank needs to store enough air where the compressor doesn't run continuously. The tank size also creates a buffer that allows for air regulation. The target/regulated air pressure should be 50 to 60% of the maximum psi rating. When you apply these factors to the specified unit it's performance become questionable.

Cleaning the brush is critical when painting multiple colors and you need to run air/cleaner through the brush. This consumes a lot of air and will have the pump cycling a lot. The last thing you need is for the unit to overheat and shut off in the middle of a coat. You need at least 35 to 40 psi continuous to shoot a fine enough coat to cover the detail in N-Scale items. I don't think that unit can do that.

I would just wait for the next financial windfall to get a HTC 30A. After that you will not have to worry about a compressor again.
It's switches on at 90 psi and shuts off at 116 psi. You will never see the effects whenever you regulate below that 50% mark.

I have the Badger version of the HTC 30A from the mid 90's and it still runs perfectly. I know it is double the price but after all this would be your second compressor.

Inobu

Thanks for the comments ;)

My "future use" won't change much regardless of whether I get better. I don't intend to be a pro and do very fine detail work. I don't intend to custom-spray N-scale rolling stock for example, apart from perhaps a clear coat. I'd probably use store bought spray cans for everything if they weren't so expensive (not to mention impossible to mix colors ;)). I've talked about that with the owners of the store, and they figured this would work fine (even though it's in their best interest to sell me more expensive stuff.)

The price is also not an issue (getting tax money and holiday money within 2 weeks from each other, both unexpected ;)), but the weight of the 30A is a no-go. I need to be able to move the compressor from to attic to the hobby room to the garden etc.. Not counting the fact that the attic stairs are terribly steep and not all too stable, my bad shoulders means that's just not gonna work. I can carry it, but I won't be able to do much else the rest of the day due to a very probable splitting headache ...

[inobu]

inobu - I miss this post where you used my compressor. Thanks!

I used the specification data for the Sprint Jet Air Compressor and may not have clarified my thoughts clearly. The specifications  that companies post on their data sheets are some what misleading. Although they state max and min values, these values do not reflect functional or effective values. Stating specific values like that have the tendency to detract from consumers performance perception which companies try to avoid. They try to build an impressive feature list and fudge on the specs a bit.

The one feature that appears to be a plus in the Sprint Jet Air is actually a detriment (Bleed valve airflow adjustment to adjust air pressure). A bleeder valve dissipates the air which induces a loss of air more so than regulating air. Because there is no reservoir/tank to preserve the air, it is just released or lost. Air is measured in volume or a rate in which it is displaces, cubic feet per minute (CFM). The Sprint Jet Air can move .64 CFM where as the HTC 30 can do 1.75 CFM. To put things into perspective an automotive paint compressor operates at 8 CFM or more. This also correlates to the size of the object being painted.

Airbrushing is a method of forcing air through a valve creating a vacuum. As the paint is sucked from the paint cup it is atomized into a mist and sprayed onto a medium. The better you can control and regulate the pressurization the better you can atomize the paint the better the results. The type of paint, its viscosity and the ability to atomize the paint into a mist is controlled by the air flow and pressure that your compressor can sustain. It is these fundamental facts that leads many from using these smaller compressors.

From my experience these smaller compressors are good for painting tiny piece. Where each stroke is just a quick burst of paint and nothing else.
Inobu

[inobu]

Yes, it does have weight to it and can be a hassle carrying up stairs but other than that I recommend it. If you are not going to do a lot painting then you are probably doing the right thing for your needs.

In General:

Someone who likes detailing, then the larger airbrush type compressor is better. It can cover a broad range of brushes.

The Paasche brushes for the small detail stuff and the touch up gun for the larger areas.

It can really do a lot for you.

Inobu

[Martijn Meerts]

Thanks again. I'll probably stick with the 16A compressor and H&S infinity brush. Should the need arise later, and should I get enough room for a dedicated airbrushing workstation, I can always buy a heavier compressor and continue using the 16A as a portable one. That way it's not a waste of money either way ;)

[SONIC883]

I will take the H&S Evolution 2in1

With this Airbrush you 0,15/0,2/0,4/0,6 mm (Düse)
and a 2 or 5 ml tank.

for me the ultimative allround airbrush.

For really fine details a Iwata ..?.. was the right choise

I tryed airbrushing 10 Years ago, but not for modelling. After i saw that I haven't much time for the hobby I have sold all my airbrush stuff.

[Martijn Meerts]

The Evolution and Infinity are nearly the same. Infinity also has 0.15/0.2/0.4 and 0.6mm needles. The only difference is that the Infinity has the quickfix system built-in, on the Evolution that's an option.

They are actually so similar, that many of the spare parts are shared between the 2.

[SONIC883]

Right, the are most identical but the infinity is more for fine arts. you can regulate the maximum of color. But when you want a dotty effect (sparkled?) you use more color and less air. that is easier to do do with a non regulated airbrush IMHO.

With my old Iwata with a 2 mm needle I get thinner and cleaner lines as with the Evolution.

You will have much fun H&S airbrushes. Both are good airbrushes.

Be careful with thinner based colors. The joints and gaskets can get damaged. Have a look which material they are made of.
When you use acryl colors you need only wather and a little bit spiritus (or windowcleaner with spritus).
For stoage I give vaseline at the needle. Only a thin film. Sometimes I add a little bit to the other meachanic, too. Before you begin to work spray spirtus, than clean the needle with a fabric.

[Martijn Meerts]

As far as I know, if you open the quickfix to the max, you basically have a non-regulated airbrush. The reason I want the quickfix is to make it easier to do shadowing on Gundam models. Just limit the amount of paint with the quickfix, and you won't have to worry about accidentally adding too much color. Especially for a beginner like me (who doesn't really want to be a pro ;)) that sounds good :)

For paint, I'll probably be using only Tamiya and Gunze acrylics. And thanks for the cleaning tips, I haven't cared much about cleaning the cheap one I have now, because it's not even worth spending too much time on =)

[SONIC883]

Yes, wenn du not lock it you have an open one, but when you work with you call pull it up the mechanism. I haven't small hands, so I must my fingertipp of my forefinger at the screw (I had sprayed with two hands, the left hand above the other hand and the brush).

When you like to shade your models don't forget to spray in rectangular. That is one of the basics.
Try first spray spot from smallest (less paint, more air, small distance to the paper) up to bigger spots (more paint, more air, more distance).
With the same technic try thin and strong lines. But never forget to spray rectangular. Only do that when you know what you want

[quinntopia]

Thanks to Inobu and the others on this thread, I've been able to make some progress with air-brushing.  In retrospect, I was using an ancient badger compressor that was leaking or couldn't get up to pressure, thus despite my Paasche VL brush, air-brushing was always a frustrating and aggravating experience.  I was always blaming the paint (and was endlessly thinning down my paints to the point of ridiculousness!), but this thread put the attention on the real culprit...the compressor.

So I ended up going with what may be a short term solution, but so far has been working excellently for airbrushing the rails of my code 80 Unitrack.
This is the unit I ended up getting: http://www.harborfreight.com/air-tools/oilless-compressors/1-3-hp-3-gallon-100-psi-oilless-air-compressor-97080.html
Clearly NOT top of the line....    But I am very pleased so far with the performance (of course, considering my previous state, that may not be saying much).  I did take some care in selecting this compressor....not only was the 3 gallon tank an important factor, but the 0.6 to 1.0 scfm seemed pretty good (especially in this price range), but most of all didn't want to invest a lot of money into something that would be a futile investment...on the contrary, this has renewed my enthusiasm for air-brushing!

I also should tip the hat to CaptO....he mentioned HarbourFreight, which I had never been too, and I've been giving the other big box stores enough money!

[KenS]

How is the noise level? 

I haven't done a lot of airbrusing (mostly track and solid-color building repaints), but I'd stopped altogether when I decided to stop using laquer-based paints about ten years ago, because my badger compressor and airbrush just didn't seem able to handle Poly-S paint.  I've been following the discussion here about pressure requirements and thinking of getting a new compressor (and airbrush) myself, but for me noise is going to be a factor since I tend to work late at night and the walls are thin.

[quinntopia]

How is the noise level? 

Its very noisy, but for me that's not a problem as my layout and all of my airbrushing occurs out in the garage.  This would definitely not be the right choice for a compressor if noise is a concern.   So far that is the only drawback I've found.