Fine lines from an airbrush

 I'm no expert, but my understanding is, thin paint, low pressure, brush very close to the subject and paint flow closed as much as possible (which will require very thin paint).

 Above all, lots of experimentation. Most of these variables will vary with each paint bottle and even weather conditions.

What Dave said is true but there are other things to consider as well such as skill level on the airbrush. A siphon-feed airbrush is going to take more pressure to reliably feed paint out of the cup and into the airbrush. The best thing to do is to experiment!

Get an old kit or something plastic and just try different settings of paint viscosity and distance from the object until you find what works best for you. 

Things are a little limited with a 2oo series airbrush as it is a single-action design and they don't have the capability to spray as fine as a double-action model.

MikeV wrote:

What Dave said is true but there are other things to consider as well such as skill level on the airbrush. A siphon-feed airbrush is going to take more pressure to reliably feed paint out of the cup and into the airbrush. The best thing to do is to experiment! Get an old kit or something plastic and just try different settings of paint viscosity and distance from the object until you find what works best for you.  Things are a little limited with a 2oo series airbrush as it is a single-action design and they don't have the capability to spray as fine as a double-action model.

What Mike said, only I'll argue the point that single action CAN be better at fine lines. It all depends on the model. The 200NH is capable of fairly thin lines, but better results can be had with the 200G, 200SG and especially the 200-20 "detail" brush which IMHO are superior to gravity fed. I have both the 100LG and the 200-20, and I can get much finer lines with the single action 200 as I can dial in the line width and not deviate from that width. Meanwhile I'm all over the map with the dual action 100LG.

Now Mike is a real artist with an airbrush, while I'm just a wannabee. Your results may vary, mine sure do!

MikeV wrote:

Things are a little limited with a 2oo series airbrush as it is a single-action design and they don't have the capability to spray as fine as a double-action model.

It's more a limitation of the single-action design of the 200 series making it difficult to do so rather than the 200 series not having the capability to do so The 200 series shares its head assembly with it's double-action cousins, so arguably it should be able to spray just as fine a line.

In practice, one can spray pretty fine lines with the 200, the problem is that being a single-action design, the paint starts to flow as soon as you hit the trigger. This makes it difficult to start a line cleanly (eg. in the middle of a panel) 

With a  double action brush you can start the airflow and then bring the brush to bear on the spot where you want to start painting before you ease back on the trigger to start the paint. With the 200 (and other single-action brushes) your paint flow is pre-set and starts immediately when you press the trigger. While it can be done with practice, it's trickier to do than it is with a double action brush.

Another consideration is that you will have to have your needle set to a minimal paint flow and depending on the type of paint you're using, this can lead to rapid onset of "tip dry", requiring more frequent cleaning of the tip. Often with a double-action brush you can "cycle" the needle to help keep it "clean" (for want of a better description).

Another problem you may encounter is spattering from paint building up on the tip. As you paint, (with any airbrush), paint can accumulate on the tip/nozzle area. Release the trigger and the next time you press it, this accumulated paint can be deposited on your model in the form of spattering.

This is less of a problem with a double-action brush because you can point it away from the model, start the air and then bring it to where you want to paint. Not so with a single-action brush were it has to be pointed at the part you want to paint before pressing the trigger. (Ok, you can sort of do the same trick, but you will get a little overspray on your model.) You can also get into the habit of wiping down the tip before starting each new area you're painting.

MikeV wrote:

Things are a little limited with a 2oo series airbrush as it is a single-action design and they don't have the capability to spray as fine as a double-action model.

I think it depends on the airbrush model and the airbrush user more than simply double action vs. single.  For an apples-to-pomegranates comparison, with my double-action Aztek 430, I had difficulty getting consistent results with it, even when using its fine tip.  In contrast, the first time I used my Badger 200 NH, it was to do a free-hand camo on a 1/72 tank, something which required reasonbly fine control and which exceeded what I could have likely accomplished with my Aztek.  With the single action Badger, it was easy.  I later picked up a Paasche H and found it equally easy to control.  Although it's been four or five years since I last touched the Aztek, I don't recall that even under the best of circumstances that its fine line control was really that much better than the Badger or the Paasche.

Phil_H wrote:

In practice, one can spray pretty fine lines with the 200, the problem is that being a single-action design, the paint starts to flow as soon as you hit the trigger. This makes it difficult to start a line cleanly (eg. in the middle of a panel)  With a  double action brush you can start the airflow and then bring the brush to bear on the spot where you want to start painting before you ease back on the trigger to start the paint. With the 200 (and other single-action brushes) your paint flow is pre-set and starts immediately when you press the trigger. While it can be done with practice, it's trickier to do than it is with a double action brush.

With either my Badger or my Paasche, I've never found any difficulty starting in the middle of a panel.  Perhaps the trigger is in theory, an on-off binary sort of thing, but in practice there is a small range of vertical motion that allows you to "feather" the initiation of the painting, so you can start the painting without getting that immediate blast of paint.   

Phil_H wrote:

Another consideration is that you will have to have your needle set to a minimal paint flow and depending on the type of paint you're using, this can lead to rapid onset of "tip dry", requiring more frequent cleaning of the tip. Often with a double-action brush you can "cycle" the needle to help keep it "clean" (for want of a better description).

I probable agree with you there, and that seems to be the real limitation of fine line control.  I know I can dial in the Badger for some extremely narrow lines, i.e. less than a 1/16" but after painting a bit, tip dry sets in, and stops the paint flow.  With it adjusted to a wider flow, it's not as much of a problem.  Of course, when building scale models the question is how fine a line do you need?  Both the Badger and the Paasche can get narrow enough to handle free-hand camo on a 1/72 tank, so either will really handle most modeling situations.

On the double action flip side, if you start getting tip-dry and want to open up the tip a bit to compensate, you run the risk of overdoing it.  I'm sure that after enough hours painting with it, you develop the precise trigger control to avoid that problem, but I certainly never got to that comfort level with my Aztek.

Phil_H wrote:

Another problem you may encounter is spattering from paint building up on the tip. As you paint, (with any airbrush), paint can accumulate on the tip/nozzle area. Release the trigger and the next time you press it, this accumulated paint can be deposited on your model in the form of spattering. This is less of a problem with a double-action brush because you can point it away from the model, start the air and then bring it to where you want to paint. Not so with a single-action brush were it has to be pointed at the part you want to paint before pressing the trigger. (Ok, you can sort of do the same trick, but you will get a little overspray on your model.) You can also get into the habit of wiping down the tip before starting each new area you're painting.

I have never encountered that with either the Badger or the Paasche, although ironically, it used to happen all the time with my Aztek.  What happened was that the Aztek tip has four tiny little projections, essentially a tiny crown to pressumably act as a guard when the needle is poking out, and they were close enough to the needle that they would collect paint which would eventually blow onto the model.

In contrast, the crown on the Badger is wider and therfore further from the tip, so it doesn't collect paint, or rather the overspray that does collect has mostly dried, such that it doesn't blow onto the model.

Andy

P mitch wrote:

So I'm getting more into airbrushing and now need to go for the finer lines. I'm using a badger 200 which should be fine for thinner lines. My "simple" question is do I need to drop the pressure of the airbursh to make a finer line?

I too have a Badegr 200 NH, and it does paint a narrow pattern pretty easily.  Based on my regulator gauge, I typically spray in the 14 - 15 PSI range for fine work.  It will siphon all the way down to about 10 PSI, but when the pressure is that low, the atomization suffers, and there is not much improvement in control.

P mitch wrote:

I understand I need to restrict the flow of the paint but the second part of the question is how how little paint do the "experts" think should be coming out of the brush?

Basically adjust the needle until you're getting the desired pattern width.  For the narrowest lines, you need to have the tip pretty close to the model, maybe 1/2" or even a bit less.  Just unscrew the needle until the pattern is good, and you're ready to paint.  When doing fine lines, I find that adding a bit more thinner than normal is useful.  Because all paint is different, thus making thinning ratios a meaningless term, I can't quantify it further, but do experiment with it to get a "feel" for how thin you need to make your paint.

Always keep a piece of scrap plastic handy to test with before painting on your actual model. 

Andy   

Bgrigg wrote:

MikeV wrote: What Dave said is true but there are other things to consider as well such as skill level on the airbrush. A siphon-feed airbrush is going to take more pressure to reliably feed paint out of the cup and into the airbrush. The best thing to do is to experiment! Get an old kit or something plastic and just try different settings of paint viscosity and distance from the object until you find what works best for you.  Things are a little limited with a 2oo series airbrush as it is a single-action design and they don't have the capability to spray as fine as a double-action model. What Mike said, only I'll argue the point that single action CAN be better at fine lines. It all depends on the model. The 200NH is capable of fairly thin lines, but better results can be had with the 200G, 200SG and especially the 200-20 "detail" brush which IMHO are superior to gravity fed. I have both the 100LG and the 200-20, and I can get much finer lines with the single action 200 as I can dial in the line width and not deviate from that width. Meanwhile I'm all over the map with the dual action 100LG. Now Mike is a real artist with an airbrush, while I'm just a wannabee. Your results may vary, mine sure do!

Wow Bill! I am surprised to hear you say that! That is interesting.

I've been airbrushing for decades...and fine lines are always a challenge...I can get my Iwata to do very fine lines. However, now the human factor arises...a steady hand...as we get older our hands shake, even the slightest tremor will cause an otherwise straight line to look like a curved one down the center of a roadway.

I find I still need the mechanical advantage...such as tape or a masking guide. The edge of a ruler will help you guide the tip of your airbrush along not deviating...straight. For camo patterns with lots of fine squiggly lines...thats easy!

Bgrigg wrote:

Mike, what part? That I don't agree with you, that you're an artist, or that I can get thinner lines with my 200-20?

Oops! Sorry Bill, the part about you getting finer lines with a single-action....and a siphon-feed at that!

HawkeyeHobbies wrote:

I've been airbrushing for decades...and fine lines are always a challenge...I can get my Iwata to do very fine lines. However, now the human factor arises...a steady hand...as we get older our hands shake, even the slightest tremor will cause an otherwise straight line to look like a curved one down the center of a roadway. I find I still need the mechanical advantage...such as tape or a masking guide. The edge of a ruler will help you guide the tip of your airbrush along not deviating...straight. For camo patterns with lots of fine squiggly lines...thats easy!

Gerald, good points my friend. 

I am curious if you use one hand or two to hold the airbrush? 

That can make a huge difference.

Also, if you can possibly get your elbows pressed against your torso and rotate your torso as you move left to right, painting a line will be straighter. Another T-shirt airbrushing trick.

 Just curious, why would you try to freehand thin straight lines on a model? If I wanted a thin, straight line, I'd mask it.

  For thin squiggly lines in camo, or mottle, or even exhaust staining, the initial pressure pulse of a single action doesn't seem to be a big problem, at least not in 1/48 or larger. Then again, maybe it would be in tiny scale models.

MikeV wrote:

Bgrigg wrote: Mike, what part? That I don't agree with you, that you're an artist, or that I can get thinner lines with my 200-20? Oops! Sorry Bill, the part about you getting finer lines with a single-action....and a siphon-feed at that!

The 200-20 is a siphon feed, this is true, but it's also a detail brush. It doesn't have the crown regulator, which means I can get right up to the surface with the needle. With paint thinned more than I normally do for gravity fed, atomization is still pretty good at 15 psi, and the dial used to position the needle is quite finely threaded. Properly set up I can do pencil lines all day long without deviation. A task I haven't mastered with my dual action 100LG. The key word being the word "I". You, on the other hand, are expected to do MUCH better!

This brush also has the same needle size (not length) and head assembly that the 100LG has, so all things being equal, other than siphon feed!, they are in effect the same brush.

And of course the 200G and SG are gravity fed single action, so there is very little difference between them.

Bgrigg wrote:

The key word being the word "I". You, on the other hand, are expected to do MUCH better!

Ouch! Why do I feel the pressure is on me?

Well my friend, all that matters is what works best for you and I am glad you are at least getting the results you are looking for in an airbrush. 

Some people never seem to get a grasp on it and quit trying and I can understand their frustration. You have to be somewhat of a masochist to learn to be very proficient with an airbrush.

I also appreciate your kind words of my airbrush skills. I appreciate that you feel the way you do even though I am just another airbrush user and not Yoda on the airbrush.