Painting & Finishing Models

Introduction

There are a variety of how-to books out there that cover the painting and finishing of aircraft models, but one doesn't stand out in particular for me on the techniques that work for me. Everyone has a slightly different approach to painting a model and you still see hand-painted models beating out airbrushed models on the contest tables. For what it is worth, let me share my techniques for aircraft painting and finishing. I've seen what the artists who can hand-paint models turn out. I'm not one of them, so I'll stick to my trusty airbrush. I found my level of success versus frustration is directly proportional to the use of good tools.

Tools

1. Air Brushes

There are many different brands of airbrushes out there, but they essentially break down into two types: single action and double action. A single action airbrush maintains a constant air pressure at the nozzle when the trigger is pressed and the air pressure is adjusted at the compressor/regulator. Paint flow is adjusted by moving the paint nozzle in or out of the airstream. On a Pasche single action airbrush, this is done by adjusting (screwing) the paint nozzle at the tip.

Double action airbrushes can feel odd initially (like you're afraid to chew gun or breathe when using the brush) because you are using the same trigger to regulate airflow AND paint flow. The harder you press down on the trigger, the more air pressure is released through nozzle (up to whatever pressure level you've set in the regulator). The more you slide that same trigger forward, the more paint can flow into the airstream. Full down and forward on the trigger and you're getting maximum air and paint moving through the airbrush. Once you get the hang of the double action airbrush, you can shift from covering larger areas with color to drawing a demarcation line for a camouflage color at the mere twitch of a finger.

2. Compressors

Years ago, I started out with one of those typical piston pump compressors that would pulse air through the airbrush, and while it did an okay job, the diaphragms would wear out every year or so, and the pump itself wouldn't last much longer than two diaphragms. Why? They are designed for 30-35 psi output and these compressors run continuously whether you're spraying or not. If you airbrush at 30-35 psi, you won't be able to paint small areas with precision but you can do one heck of a job spraying out that base coat!

If you put an air pressure regulator on them, the diaphragms will wear out even faster. This isn't a defect in the compressor; they just weren't intended for extended periods of back-pressure. When you're between sprays on your airbrush, there is nowhere for the excess pressure to go except around the diaphragm. Another 'feature' of these compressors is they are noisy. This is fine if you're single or wanting to be that way again...

I finally invested in a nice Badger air compressor that has an air storage tank, automatic pump shut-off, and is only as loud as a quiet refrigerator. The advantages of an air compressor like this are: smooth, pulse-free airflow; constant regulated air pressure; relative silence while I am trying to concentrate on the model; and reliability - this air compressor is now over 12 years old and still runs, but it started locking up and I couldn't seem to connect with the Badger customer service folks, so like my airbrushes, I've switched to an Iwata compressor. You can see this beast here.

3. Miscellaneous Essentials

If you have a decent compressor and airbrush, invest in an air regulator that has an easy-to-read pressure gauge and a water trap. The water trap will collect any condensed water vapor before it finds its way under your paint. This is annoying when you're shooting acrylics, and downright frustrating with enamels!

If you have more than one airbrush (i.e. a double action and single action airbrush), get an air line splitter with cut-off valves. This allows you to have multiple airbrushes hooked up at the same time so you're not disconnecting and connecting air lines to change brushes. Despite all of the hype out there on double action airbrushes, the single actions are quicker to clean and are excellent for laying out base colors and larger areas.

You'll need mixing cups to dilute your paints. I get the small cups that are disposable after one use from Hobby Lobby. While you're there, pick up a box of 1000 ice cream sticks. These are absolutely the best (and cheapest!) mixing sticks that are handy for other hobby applications as well.

Painting

These days, there even more choices when it comes to paint than airbrushes! Nevertheless, there are three essential types of paint for modeling: acrylics, enamels, and lacquers. Some people will tell you that they only use one type, but there is good reason to know how to use all three.

Acrylics are excellent for painting indoors. There are no harmful vapors to worry about (though you should still have adequate ventilation) and depending on the brand, the paints are nearly bullet-proof after drying. I use Tamiya and Gunze Sangyo acrylics whenever possible. Tamiya offers a fair selection of colors and Gunze offers a nice variety of color-matched paints, second in selection to Testors Model Master Enamels.

I still use enamels, specifically Testors Model Master paints, because I don't like to waste time mixing colors. I like to go to the shelf, get the bottle, and shoot the color, repeat as necessary. The Testors enamels are color-matched and easy to use. When I go to the store to pick up a new bottle of a given color to replace my three-year-old bottle of that same color, I know that the colors will match. For enamels, I use my paint booth to get the vapors outside.

I also use lacquers, specifically Alclad II metalizers, though I am using the Tamiya lacquer colors for certain applications as well. With Alclad II, there is no better way of obtaining natural metal finishes that you can mask and paint over. With lacquers, if you spray indoors, it is vital you have a paint booth and adequate ventilation as these vapors will take you from zero to stupid in just a few minutes of exposure.

1. Preparation

I generally set my compressor's regulator for 15-18 psi. This is a good pressure to move paint onto the model without drying it in-flight or splattering it everywhere.

Acrylics: I use my handy paint mixer to get the pigmentation mixed into the carrier, then pour what I need into a mixing cup. For Gunze colors, I mix with 1/3 Isopropyl Alcohol (the 99% type) to 2/3 acrylic. Tamiya acrylics are thicker, so I mix 50-50 Tamiya Acrylic with Isopropyl Alcohol. I am aware that some folks use windshield wiper fluid as their acrylic thinner, but I have no experience with that medium.

Enamels: I mix 2/3 Testors Model Master Enamels with 1/3 Testors Model Master Thinner. The paint should be as thin as milk, so if you get a color that is thicker, just add a little more thinner.

Lacquers: Alclad II shoots beautifully straight from the bottle. Be sure to mix it thoroughly at first and again before refills as the metalizer settles rather quickly out of the medium.

2. Cleaning

The quickest way to botch a paint job is not to clean the model first. Styrene parts have varying levels of oils on their surfaces from injection molding. These oils come off with standard dish soap and warm water. If you don't wash the parts, the paint will not adhere to the surface and you'll see your paint start to come back off your model. Any dust left over from sanding or filing will also interfere with your finish, so use an old toothbrush to get into the panel lines and remove any left-over dust. Once the model is clean and dry, give the model a quick rub-down with Floquil Plastic Prep. This stuff not only cleans up any last minute fingerprints (also a barrier for paint), but it will temporarily take care of any static electricity that would attract dust particles, cat hair, whatever to your clean surfaces.

3. Painting

Modelers have different techniques and preferences regarding paint. Rather than try to quantify what others do, let me share my perspective from a modeler’s point of view:

Regardless of the subject, there are certain realities about painting models:

1. Matte paints are easier to apply and dry quicker, but will cause decals to silver if applied directly over the paint
2. Gloss coats are easier to use with decals, but dries slower
3. Semi-gloss paints tend to be a good compromise with decal use directly over the paint and while slower to dry than mattes, they are usually faster to dry than gloss colors

I like to shoot matte colors in my modeling. When I get some time and modeling momentum going, the last thing I want to do is wait for a day or two for my first coat of paint to dry! Okay, so patience isn’t one of my ‘gifts’. If the only way to get a given color is to use a gloss or semi-gloss paint, I’ll plan accordingly, but this is a rare event. Because I use matte paints, I will leave the model to dry completely once the last color is down. I know the model is mostly cured when the smell of fresh paint is no longer detectable on the surface of the model. At this point, I’ll take an old t-shirt and buff the model down to smooth out any rough surfaces left by the matte paints. I’ll perform any touch-ups needed to the paint job, let that set for a short time, and then buff the new paint smooth with the surrounding surface.

Don't be afraid to experiment as you'll do this over and over again as you change airbrushes and techniques in the future. Find the finger position that provides a comfortable flow of paint without overspray or splatter. Find the finger position that allows you to paint a solid line with no splatter. Keep the surface that you're spraying perpendicular (90°) to the airbrush's airflow.

Do allow your paints to dry before moving on to the next color. I shoot flat colors because they dry quickly and can be handled within 10-15 minutes, depending on how thick a coat you've applied. If you're modeling high gloss automotive subjects, stick to the gloss colors. If your flat color feels dry, smell it. If it still smells, then let it dry a little longer as you may run into problems later.

4. Buffing

Once the colors are applied and it is time for decals, we must smooth out the surface. First, I use an old t-shirt and buff the model smooth. Flat paint leaves a course texture that will not accept decals without silvering. Gently buffing the paint smooth will significantly improve the appearance and reduce risk of silvering. When you're done, if you need to retouch anything because you buffed through the paint (it takes a little getting used to), touch up the paint and re-buff after it is dry. Now smell the model. If the paint still smells wet, set it aside for a few hours. Buffing can get to areas not completely dry.

5. Gloss Coat

Once the model is dry, apply a gloss coat over the whole model. Make sure any windows, open interiors, etc., are masked off first. You can use Tamiya or Mr. Color clear lacquers, Tamiya or Gunze clear acrylics, or do what I do - Future Floor Wax. I dilute the Future 50-50 with 90% Isopropyl Alcohol and apply it to the model. When it is dry, I buff the surface again to eliminate any irregularities in the clear surface. Reapply the Future mixture until you get a uniform gloss finish. Is it true that Future works on floors too?

6. Decals

With the clear coat down, I’ll take whatever time is needed to apply the markings and stencils, then let them dry completely (usually overnight). I will clean up any decal adherents that will flow away while drying, then apply another gloss coat to seal the decals. When that coat is dry, then I’ll apply whatever matte or semi-gloss coats are required before moving on to weathering the project.

Apply your decals using a good setting solution. Microscale has a good two-part decal setting system available at most hobby shops. Once the decals are dry, make sure there isn't any silvering in the clear edges of the decals. Re-applying the setting solution to problem spots will usually help. For stubborn decals, I keep a bottle of Solvaset handy. Usually an application or two of that will get the most stubborn decal to conform. Apply another coat of Future 50-50 mix to seal the decals.

7. Panel Lines

To bring out the panel lines, you can use a brown or gray-based oil color. For the recesses around flight controls and flaps, I use a black oil color. I buy small tubes of these oils from Hobby Lobby and a can of Odorless Mineral Spirits from my hardware store (much cheaper there!).

I mix a very small dab of oil into a mixing cup of Odorless Mineral Spirits until the thinner is no longer clear. Use a thin brush to apply the oil to the panel lines. Don't worry about any messes until after it dries. If the panel lines are a little too light in spots, apply a little more. If it is too dark or there is a slight mess in a spot, use the damp Q-Tip to clean up. Dried oils respond well usually to water, but you can also use the Mineral Spirits. Don't attempt to use oils directly on flat paint as you'll see the oils run all over the coarse texture.

8. Final Coat

For glossy aircraft (airliners, VIP aircraft, etc.), I apply the same clear coat mixture to the surface to seal the oils.

For tactical aircraft, I take a combination of 1/3 Future, 1/3 Tamiya Flat Base, and 1/3 Isopropyl Alcohol and apply that to the surface. Tamiya Flat Base is a milky acrylic that is not a color but will turn any Tamiya gloss color flat when mixed together. It does a great job of turning Future flat too. By adjusting the proportions of Future to Flat Base, I can get semi-gloss and variations of flatness that makes the model look like it has been re-painted in the field without even altering the color.

Conclusions

Well that's essentially it. We didn't get into weathering, but we'll go over that another time. These are the steps I use to turn out my models, but as I said in the beginning, there is no one right way. Read how others go about finishing their projects and adopt bits and pieces from each modeler to come up with your own technique. Of course, don't get too comfortable with your techniques as someone is always coming up with a better paint, tool, or technique and you'll wonder how you modeled this long without that new feature. Consider this a starting point if you don't have one.

Now that you've read my painting process, and many folks follow a similar process, you’ll have to realize that if you agonize over the accuracy of a given color, you’ll literally change that color as you transform that paint from a flat to a gloss and back again. If you’ve done any pre-shading or fading/weathering, then all of that effort for pure color accuracy goes out the window. The best thing is to relax and embrace the reality that paints will fade and colors change depending on the colors underneath, the thinners used, etc. - and that is on the real aircraft/armor/whatever subject! You can go here to read up on colors and available paints.

Now go build something!