Airbrushes and thin lines

Very Good and Equally informative post that Im sure will help clear up some common mis-conceptions!

Mike thx for the post, Im starting to get a much better feel for airbrushing and if I want or need to upgrade and what i should get if I do. Thx again for all the help.

MikeV has made a very important post here regarding various airbrushes and their "fine tips". As an example and for the benifit of other modelers I did a performance spray test using two airbrushes several years ago on rec.models.scale I'd like to share with you all to validate the difference between illustration airbrushes with their fine tips and hobby-designed AB's with their larger nozzle/tips for achieving fine lines.
One of the airbrushes was the Iwata HP-C gravity-feed double action AB with a very small .3mm tip and the other was the time-tested, reliable 'ol Paasche-H single action bottom feed with the #1 tip(approx.5mm). For the test I used Model Master enamels thinned 2:1(paint to thinner) using it's thinner for consistancy. Because some hobby paints differ in viscosity from bottle to bottle, I chose a color from the Model Master II line which according to Testors Documentation its paint formula is thinner in viscosity than the standard FS colors. To give both airbrushes a fare test I prepaired the paint even futher by shaking , mixing, straining and slightly warming it in warm tap water. Using a scrap model kit as the test subject I began shooting with the HP-C. To get a fine line I had to dail down the air presure a bit to around 9 to 10 psi, then barley pulled back on the trigger releasing a tiny dot of paint on the test models surface. The results was surprising to say the least; the atomization (tiny paint droplets broke-down by airflow) was ok but not the "super-fine" atomized soft mist as I anticipated. Instead there was some spatters along the spray line after every line I sprayed. Next I loaded the Paasche-H with the same paint, this time I dialed up the air preasure as suggested in the instruction manual that came with the airbrush to approx 30 psi. To get a fine line I very slowly turned the knurled knob on the nozzle to release a very tiny dot of paint. The result was awesome!, The spraying line measured approx 1/32 inch, finely atomized, soft mist with no splatters or specks! More impresive with the H is that I could hold this fine line consistanly with little to no clogs. It was evident to me that the Iwata HP-C with it's smaller tip and nozzle required even thinner paint to get it to spray as advertised(or as I expected it to). So I took the same paint and thinned it 1:1(or 50/50 paint to thinner) , resprayed several lines on the test model and noticed the following significant differences in the paint (on the model). The spray characteristics were similar in the first test only this time the lines were more "satisfactory", finely atomized and soft, measuring approx 1/32 inch. However the paint didn't cover well, required several coats for even coverage. So as you can deduce from this simple test, the fact that the Iwatas .3mm tip would sway one to believe that it will produce magically perfect fine lines with our thicker hobby paint was not true. It was the old time tested Paasche-H with it's larger #1 tip designed for thicker viscosity hobby type paints that acheived the fine lines I was looking for. Keep in mind what your needs are, ie. autos, large or small scale aircraft, sci-fi etc.. to determine the airbrush suited for you. In the case of my test I needed to know which airbrush could help me free-hand airbrush the best soft atomized fine lines of at least 1/32 inch to 1/16 inch. I model small 1/72nd scale modern jets , some with intricate multi-color camo. These days the Iwata Revolution HP-CR, Eclipse HP-CS and Paasche-H I own are all designed for thicker viscosity hobby-type paints and provide excellent perfromance. I hope this post helps someone in their modeling endevours! Gook luck.

Greg,

Thanks for that information, that was very imformative and should be very helpful to many.
Someday I am going to try a test like that with all of the airbrushes out there. Get somebody to buy them for us and we can both do independant tests and compare notes my friend.

I had a guy on another forum disagree with me on this topic after I had said that airbrushes like that are specialty airbrushes. He said that he has been using the Paasche AB turbo for 10 years on models and disagreed with my statement that they were specialty airbrushes, to which I say he is wrong and an AB Turbo for modeling is absolute overkill. Maybe you can make it work, but as you found out with your HP-C it is no easy task and the AB Turbo shoots a much finer line than almost any, if not all airbrushes made. I have been told by many that it is the most difficult airbrush made to master and many people get rid of it out of frustration.
I think that some people buy these illustrators airbrushes just to be able to brag that they have a finer tip than the next guy.

Mike

QUOTE: I think that some people buy these illustrators airbrushes just to be able to brag that they have a finer tip than the next guy.

Ironically, that's the opposite of what you usually hear guys bragging.

MIkeV,

I love to share what I've learned over the years with other modelers and I hate to see modelers make the same mistake I made with regard to selecting an airbrush and their expectations of it. I don't have all the answers but hopefully it will provide some insite, if not it could be an expensive mistake they will not soon forget....I know I haven't yet banghead]