I absolutely love airbrush paintings and art. I’ve had sculptured nails that were airbrushed, I’ve purchased my children totally cool airbrushed t-shirts. It is something I’ve always wanted to learn, and I bet you’ve been curious too! So today, I’m sharing some tips on how to use an airbrush through some exercises that will help us understand the principles of airbrush painting.
Principle of Operation
On a double-action aero, the trigger allows independent control of the air and paint flow rates.
By pressing the trigger vertically, the airflow is activated. The trigger actuates a piston connected to the air inlet valve, increasing the air flow rate of the aero proportional to the pressure applied. The more pressure is applied, the greater the airflow.
Pulling the trigger horizontally activates the paint flow. The trigger is connected to the needle, which blocks the paint supply to the container. Pulling the trigger pulls the needle, which releases the paint in proportion to the pressure exerted. The more you pull, the more paint comes out.
Diluting the paint
We will talk here about acrylic paint. It’s better to work with new pots. As paint fades with time, you can have bad surprises by using paint you started a long time ago (bad adhesion, flaking, fading color).
Dilution is an essential point because the quality of the paint depends on it. Acrylic paint can be diluted either with official thinner. 70% alcohol works very well too, drying even slower than 90° alcohol. The proportions are simple: with alcohol, a 50-50 dilution works well and is easy to apply. From a new jar you can make two jars. On the other hand with official thinner the proportions are 1 of thinner for two of paint. Finally, the final result is finer with official thinner than with alcohol.
- A well-diluted paint is easily sprayed, has a smooth finish, clings well but requires several passes to cover a part perfectly.
- An undiluted paint will have difficulties to be sprayed with a 0.2mm nozzle, risking to clog the aerosol (but will be fine with a 0.4mm nozzle), has a better covering power but will give a grainy finish.
- A paint too diluted is too liquid, does not stick, does not cover, and makes halos.
Problems That Can Be Encountered
- the jet as it should be: clean and regular.
- creation of puddles and drips: airbrush too close to the surface or paint flow too high. If the distance and flow rate is good, the paint may be too diluted.
- spattering: the paint is too thick, it may have started to dry if it has been in the airbrush for a while (especially if it is diluted with 90° alcohol), the airbrush is clogged … the airbrush must be cleaned in any case.
In model making we work essentially between 1 and 1.5 bars (about 14 and 22 psi). You have to make sure to use an appropriate airbrush compressor. You can find a detailed article on how to find the right airbrush compressor in this article.
Exercises to Learn the Principles of Painting with a Double-Action Airbrush
1. Learning how to position your airbrush
On a sheet of paper draw a grid of dots. Hold your aero at 1 cm from the sheet and make dots of paint on the points you have drawn.
If you hold the airbrush too close or pull the trigger too much, puddles will appear. The goal here is to learn how to aim with your airbrush and to start mastering the flow. So avoid puddles and practice making clean stitches the size you want.
2. Avoid pies at the start and finish points
We will now draw thin straight lines. The aim is to avoid making spots at the start and end of the line. Indeed if we send paint from the start, a stain is formed because of the speed difference between the hand and the paint jet. This creates an accumulation of paint at the starting point. The same phenomenon occurs when you stop the line.
To avoid this phenomenon, start moving the airbrush while projecting air before the point where the line should start, and send the paint when you reach the starting point. And conversely, at the end, stop the paint but continue the movement and stop the air further.
Make several lines until you master this principle. This way you will avoid making pies.
3. Control distance and flow rates
The distance of the aerofoil from the target is essential:
- from close, the line is fine and sharp
- from far, the line is wide and blurred
Moreover when the aerofoil is moved away without changing the flow rates, the line becomes lighter. To make a wide and opaque line, it is therefore necessary to proportionally increase the air and paint flows at the same time as you move the aerofoil away. Without sending too much product which creates puddles and drips.
Practice by making thin lines at the start and wide lines at the end, varying the flow rates. This will allow you to master the concepts of distance and flow.
4. Work on the precision of the strokes
Now we’re going to redo a grid of dots in pencil. Make the smallest strokes possible with the aerial over it, and then connect the dots with the most regular lines as possible. This will allow you to develop your skill and review the previous principles.
5. Mastering the veils of paint
The variations in flow rates offer the possibility of making very light paint veils. This is an essential point in airbrush painting, and is frequently used in model making to achieve various effects, including gradation. We will therefore make a gradient only with sails of the same paint color to learn how to master the sails.
First make a square with adhesive tape. Then with a smooth movement of the wrist from left to right and from right to left, project a very light veil over the entire surface by making the changes of direction outside the frame. This will prevent paint build-up inside the area to be painted. Then pass another veil a little more opaque, this time avoiding painting the bottom of the area. Repeat with an even thicker veil, this time painting only the upper third of the area. And finish with a very opaque veil at the top of the area.
Remove the hidden stripes and admire your gradient! This one has been made with a single color, but varying from one veil to another the distance and the rate of painting.
So much for the main principles of aero painting. We will see during the realization of the model the techniques more specific to modeling, including the gradations through the post and pre-shading. But already thanks to these basic exercises you will be able to master your tool and especially to assimilate its operation.
Cleaning the Airbrush
Cleaning is not the most exhilarating moment of aerial painting, but it is, unfortunately, an essential point that must be done at the end of each use, even regularly during long sessions during which the paint can dry in the body. A good cleaning ensures a clean spray and guarantees a long life to your aero.
At the end of use, first, empty the cup of unused paint and then spray what is left in the body. Make a first cleaning of the cup and the cavity from which the paint flows with a cotton swab soaked in alcohol. Fill the cup with alcohol and make a gargle by plugging the aero-outlet with your finger and pulling the trigger to let the air out of the cup. This will help to loosen the sludge. Then spray the alcohol.
Then remove the nozzle cap, the nozzle, the bucket if removable, unscrew the needle and push it out to the front. Thoroughly clean all parts and the body with alcohol using a cotton swab. Scrub well in every nook and cranny!
You can use the needle to clean the inside of the body and the nozzle. However, it is not recommended for aerosols that are not major brands because the needle is often fragile. You can also use a mini brush to clean between your teeth, which you can find in the toothbrush section of the supermarket. Be careful not to lose any parts, especially the nozzle and seals if your aero has them!
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