Cover

All Aboard!

Start With The Basics

Why The Track Is So Important

How Does The Power Supply Work?

Analog and DCC Explained

Layout Options Explained

Locomotives And Rolling Stock

What Should You Start With?

How Do You Create A Good Layout

More On Layouts and LDE

How to Create Realistic Scenery

Explain Weathering Techniques

How To Repair Problems

BONUS SECTIONS

Frequently Asked Questions

Glossary of Important Terms

Model Railroad Yard Design Explained Step-By-Step

Model Train Layout Track Plans

Garden Railroads

Mastering An Airbrush Step-By-Step

More Model Railroad Resources

Mastering An Airbrush Step-By-Step

For those who don't already know, an airbrush is simply a precision air driven paint sprayer. However, it differs from a conventional paint gun or spray can, because it is precision instrument that can be adjusted to achieve different and highly detailed effects.

Airbrushing can add amazing realism and special effects to any model railroad layout. An airbrush can be used for all sorts of projects from weathering buildings, adding subtle effects to landscapes and backdrops, through to adding realism to advertising signs and rolling stock.

Airbrushing is a skill that takes time and practice to master, but when done well, results in a very good finish. However, don’t expect to get a good finish first time... it takes practice.

Many airbrush artists create works that are so sharp in detail, so lifelike as to mimic the real thing. An airbrush can also be used to get the opposite effect of feather-edged, cloud-like softness... the type of subtlety that couldn't be achieved with a paintbrush. So, whether it is detail, from fine lines to wispy, or mere suggestions of color, an airbrush is a versatile tools to use on any model railroad layout.

Why Use An Airbrush

1. With airbrushing there are no tell-tale signs of brush strokes. As any experienced modeler will know, brush strokes on a model can look awful and spoil the desired effect especially when models are viewed closeup. When using a conventional brush it is impossible to achieve the uniformity in a thin coat that can be achieved with an airbrush.

2. Airbrushes can be used for large areas and the paint quantity can be varied from a fine mist to a "one pass" full coverage coat. For example spraying your baseboard, hillsides, tunnels, clouds and sky on backdrops or even a large model.

3. An airbrush can be ideal for creating weathered effects, because of the small amount of paint (vaporized) that is applied. The paint goes on nearly dry, so that the model can be handled almost immediately. With an airbrush the coatings of paint are thin meaning that fine details are not obscured as they would be by a thick layer of brushed on paint. A little paint can go a long way with an airbrush and the paint tends not to seep under masking tape (or masking Friskit liquid or Frisket film) like brushed paint does.

How An airbrush Works

This diagram shows the front end of a typical airbrush. Please note that some systems vary so this is a guide only. The airbrush shown here is often referred to as an “internal mix” airbrush. This is because the paint and air mix inside the airbrush. Internal mix airbrushes combined with double action (see definition below) take more effort to master but offer more control over the painting process.

With “external mix” airbrushes the air and paint are mixed outside the main body of the airbrush. They are usually single action (see definition below) , simple in design and easy to clean.

Looking at the earlier diagram you will see that the paint is an orange color, the needle is represented in blue and the airflow is represented by black arrows. Air is injected around a “tip” where the sharp needle valve is located. When the air rushes past the tip, the pressure drop draws paint from the tip. The amount of paint released is controlled by the needle valve and the flow of air. The paint is vaporized by the flow of air and is carried along to be sprayed out the front end of the airbrush onto the model being sprayed.

Here is a quick explanation of the two main types of “internally mixed” airbrushes:

Single Action Airbrush

A single action airbrush usually has a button on top of the airbrush which releases air through the airbrush when this button is pressed. Air flow control is the sole purpose of the button, because a separate knob at the rear of the airbrush controls the needle position and resulting flow of paint. In some models the amount of paint released is adjusted by turning the front nozzle before the button is pressed. Many of the lower priced airbrushes follow this principle. A basic single action, external mix airbrush is usually cheaper to buy than a double action internal mix airbrush and will be sufficient for most modeling projects.

Double Action Airbrush

A double action airbrush also has a button but this button serves a dual purpose. The button regulates both the air flow and paint flow. The button on a double action airbrush also controls the needle position which means that pressing the button releases air through the airbrush, pulls back the needle and releases a flow of paint.

A double action airbrush can be harder to master, but allows for enormous flexibility in the type of effects that can be achieved. Most professionals and experienced modelers prefer a double action airbrush.

Paint Cups And Bottles Explained

Depending on the price and style of the airbrush it could have either a paint cup or paint bottle attachment.

With a top paint cup airbrush, the paint cup is above the nozzle, so that gravity assists the paint to flow out of the tip. This is ideal for fine work because gravity feed means that less air pressure is required for any given paint volume. .

However, special care is needed with gravity fed models because the cup and airbrush body are usually one unit. This means that once some paint in in the cup the airbrush can't be put down on its side because the paint will spill out. Also, some people find that changing colors and cleaning is a bit slower with gravity fed airbrushes.

A bottom paint cup, or side paint cup, or paint bottle are other variations available. In most cases a bottle is not necessary because only a small amount of paint is required. The small cup on an airbrush usually holds ample paint.

Bottle filled airbrushes are popular with beginners, because they are inexpensive. They are not as versatile, so if you want the best results you will generally have to spend more money to get an airbrush that is more like a “precision instrument.”

Some of the side mounted cups allow for the airbrush to be placed down without spilling the paint, especially if the cup is less than half fill. However, side mounted cups don't generally use gravity feed so these airbrushes can be more sensitive to consistency of the paint being used. Depending on the brand, they can also be harder to clean.

Airbrush Air Sources Explained

Depending on how much you want to spend there are several possibilities for getting air power to your airbrush.

Air Propellant In Cans

Some of the cheaper airbrushes simply run on a disposable can of compressed air. That is how many people get started before progressing to a more permanent setup. The initial cost is cheaper at perhaps around $10 -$20 compared to $100 - $500 for a mini compressor. However, if you are serious about mastering an airbrush and intend to use it frequently or for a major project, then disposable cans will will prove to be an expensive option.

A can contains only about 10 continuous minutes of air, so for a lot of people that won't go very far, especially if you are doing a lot of experimenting. Believe me, it can get very frustrating when the air runs out in the middle of a project. Although it is possible to fit an air regulator to an air can, in most cases the air pressure starts to reduce as the can empties. This can cause an erratic flow of paint and spoil your work of art.

Although not necessarily a disadvantage, the cans tend to get cold as moisture condenses on the outside as the can empties. Be careful that none of the moisture touches your paint job as it could cause some damage.

So, in summary, disposable cans are reasonably cheap and convenient option if you are just going to do the odd spray job. However, if you are more of a perfectionist, or intend to do a lot of airbrushing, then cans may prove to be less consistent, inconvenient and expensive.

Air Storage Tanks

Another option is a large air tank of some kind. There are gas cylinders and propane-style storage tanks, but you will need to check a couple of things before getting started. Firstly, you will need to thoroughly check to see that the system is safe to use before connecting your airbrush. Secondly, you will need to know if it is capable of working reliably.

Some people use an old car or truck tire. However, you will need to understand how to use adapters and regulators. The air pressure may need to be regulated down to about 25 psi. Whether you are using a propane-style storage tank or a car/truck tire, both of these solutions will eventually run out of air and need refilling. The advantage is greater storage capacity meaning that the air will last longer than in a can.

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Air Compressors

Compressors are generally the best solution, however the initial cost can prove prohibitive particularly if you don't intend to get much use from it. In the long-run, a compressor will be the most economical and reliable option.

Before you rush out and buy a compressor, have a good think about your requirements, as the options are many and varied. For example, pictured is a Tamiya re-chargeable compressor. It uses a rechargeable 7.2 volt battery (about 20 minutes continuous running) and comes in a convenient case form. Maximum air output is about 20 liters per minute (unburdened). The Tamiya airbrush you see attached is suitable for beginners and easy to use with a trigger control.

If you need a quieter alternative, then again there are options. Silent compressors often come with a regulator/moisture trap and a small holding tank. Pictured is the Badger 480-1 Silent Compressor which is one possibility to consider.

Many smaller compressors are designed specifically for airbrushing and are generally available from hobby stores. Others can also be used for air-powered workshop tools and are available from hardware/home improvement stores. These have a tank, built in pressure regulators, and a long coiled hose.

As already mentioned prices do vary greatly depending on what your requirements are. Pictured is one reasonably economical model. This Paasche D500 Airbrush Compressor that is capable of delivering up to 30 lbs of pressure with most airbrush brands.

Quick Tip:

Selecting The Right Paint

All kinds of substances from dyes to latex, acrylic and oil based paints can be used in an airbrush provided they are reasonably fluid. The substance needs to be able to escape from the tiny hole at the front of the airbrush. If it can't escape, it will need more air pressure to force it through, or it will simply clog the airbrush.

You may choose to mix your own paints to suit your own needs, or you can buy ready-mixed colors. There are numerous brands that could be used including: Aquaflow, Createx, Polyscale, Golden, Floquil, Polytranspar, Lifetone, Wildlife Colors, Natures Gallery, Tamiya, Testor and Modelflex to name a few.

Quick Tip:

Some modelers use Future Floor Wax (it may have a different name in different countries). It is a clear liquid floor finish and can be applied as a gloss coat over acrylic paints. It can be sprayed straight from the bottle without thinning. Some modelers even dip items directly into the floor wax to give a high gloss shine.

Most paints will require some kind of thinning. If you are using a paint thinner, then use the one recommended by the paint manufacturer, because it will have been tested to ensure that the chemistry will match the paint. It is important that the thinner is not too abrasive and damage the paint structure (or your work!). A thinner needs to assist with paint flow without drying too fast.

A cheap paint sprayer (from a home improvement store) will operate using normal household paints. These are cheaper than model paints, especially if you are using a lot of white paint or black paint to lighten or darken colors. House paints are usually available in small sample pots, which will cover a reasonably large area, for a relatively low cost. Be warned however, house paints are not designed for use in airbrushes. The pigments in house paints are not usually ground as fine as in model paints, so they can quickly block an airbrush.

Mixing Paints

Always follow the manufacturers directions when mixing paints with thinners.

Disposable plastic eyedroppers (from a hobby or drugstore) are excellent for drawing small amounts of paint and thinner from the bottles. Use separate eyedroppers for the different color paints and the thinner.

Pouring paint directly from the bottle to a mixing container is messy, unscientific, and leaves dripping paint around the bottle rim. The paint on the rim dries hard making it difficult to open and close the bottles securely. Also, little flakes of dry paint can fall into the paint causing potential blockages during future airbrushing sessions.

Choosing Acrylic Or Oil Paints

The first decision is whether you want to use an acrylic water based paint or an oil based paint. Both have advantages and disadvantages:

Whether you use acrylic paints or oil based paints really comes down to personal preference. Acrylic paints are certainly easier to clean up, but when using acrylic paints it can take practice and patience to perfect the desired combination of paint thickness and air pressure. Some paints can be used straight from the bottle whilst others need some dilution with airbrush mediums or thinners. You'll need to do some experimenting depending on the type of paint you are using, the air pressure you are using and the desired effects you are hoping to achieve.

For example; a low air pressure does limit the volume of paint that the airbrush dispenses, so with low pressure the paint may require more dilution.

When diluting paints be sure to mix them thoroughly. If the paint is not mixed thoroughly, then the paint consistency passing through the airbrush could alter causing problems like erratic paint flow and splattering. Remember too, that paint left sitting for any length of time might change in consistency with the thicker paint settling to the bottom. I use the wood end of a artist brush to stir the paints I have stored in bottles. This way I can locate any clumps of thick paint before mixing the paint vigorously. Shaking the bottles is one option, but air bubbles can develop causing the paint in the airbrush to splatter.

Airbrushing is a skill that needs to be learned from trial and error.

Some people start by reading the instructions before connecting the system up. Others just choose a paint color.... and pour it into the jar.... and are then surprised that the airbrush doesn't work. After some fiddling around the airbrush suddenly starts working. Well, it works okay for a while before it starts to splutter larger drops of paint onto their precious model.

Many people give up at this point. They pour the paint back out, clean up the mess and clean the air brush. The airbrush gets put away in a cupboard where it stays for some time. Weeks or months later the airbrush is brought out of hiding with the intention of having another go at mastering the art of using an airbrush. SHOCK! HORROR! They discover that the airbrush can't be adjusted because the paint has stuck it solid! So, as you can see, there are some important things you need to know about airbrushing before you rush in.

10 important steps to getting started:

1. Read the instructions carefully BEFORE you get started.

2. Use an airbrush ONLY in a well ventilated area.

3. Prepare the area. Construct your spray booth, lay down your plastic sheets etc.

4. Prepare the surface to take the paint. Position the model ready for spraying using disposable plastic gloves.

5. Prepare the equipment and assemble the needle and nozzle into the airbrush if not already done. Attach the paint cup or bottle to the airbrush. Use special air brush paint or thin the paint with thinners, to make a more watery consistency. Turn on the compressor and set the pressure (or attach the propellant can).

6. Make yourself comfortable. Sit down when spraying if you can. Otherwise have a chair handy to sit on between spray coats.

7. Practice on paper or an old piece of wood first. Don't risk damaging a precious model before you are confident in your ability to achieve the desired effect. Even if you are very experienced you never know what is going to come out the end when you first press the button. Make testing a part of your routine. After a quick spray make any adjustments to the airbrush, air pressure, or the paint consistency. Then test again.

8. Now test spray on a similar material to the final surface. The piece of wood, plastic, or foam material should be prepared and primed in the same way as the actual subject. This is a good way to test the chemical compatibility and spray pattern.

9. Spray the underside first. Any mistakes will be less noticeable and can be corrected before spraying the visible top side. Remember also, that some paints eat into certain materials like styrofoam.

10. Cleaning the airbrush is very important. Don't leave it 5 minutes... clean it immediately after use. After cleaning the airbrush separate any parts that can easily be separated so that any remaining paint won't solidify the parts together.

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Preparing Your Workspace

Airbrushing can be a messy business so you need to keep your airbrush workspace separate from your model railroad layout if possible. You would want airborne paint particles to settle on your layout (or on furnishings, your car etc). Sometimes a rear area at the back of a garage is suitable. An old sheet can be hung up if necessary to prevent paint from falling outside the workspace.

A simple spray booth can be erected using an old cardboard box sitting on a table or bench. Cut off the top and one side. Otherwise, plastic sheets (like on real estate signs) can be used to make a simple spray booth.

Solvents and paint spray can be dangerous to your health, so make sure there is adequate ventilation, or install an exhaust hose or extractor fan.

Some people prefer to do their spraying outdoors. However, care is required because the wind can blow dirt particles (and tiny insects) into the wet paintwork. A still day is best.

Plastic garbage sacks opened out can be excellent for covering walls or laying on the ground. Old newspapers are also good, but you may want to weigh them down with some weights or bricks to stop then blowing onto your paintwork.

A toolbox or fishing box is ideal for storing airbrush parts and accessories. It pays to have everything close at hand for easy access. A pair of disposable plastic gloves is a good idea.

Another good investment is a small craft turntable. These are available from hobby shops and from chain stores like K Mart and Target. These turntables are usually made of plastic and rotate on a base. As well as being ideal for cake decorating, they are perfect for airbrushing small models. One hand can do the airbrushing whilst the other hand rotates the turntable so that all sides get painted.

Preparing The Painting Surface

Dirt and dust are the enemy of model railroad enthusiasts and artists alike. Not only does the airbrush need to be kept in a dust-free place, but also the surfaces being painted need to be kept clean, dry and free from dirt and dust. The paintwork will only be as good as the surface it goes onto. Remember, an airbrush is designed to apply thin coats, so the paint will not hide dust, dirt, grit, unevenness, water droplets, styrofoam chips, cracks or anything else lying on the surface.

Sandpaper can be helpful when preparing a surface, but remember to carefully remove all the dust afterwards. Open grit sandpaper works well for most surface although wet sandpaper is a popular option after primer coats. Those disposable plastic gloves will come in handy for cleaning down the surface in preparation for painting. The oils from fingers and hands can sit on the surface and affect the paint job, so careful preparation is essential. A small hand-held vacuum clearer may be useful.

Holding The Airbrush

Hold your airbrush much the same as you would a pen. Position your index finger over the trigger with the air-hose over your fore-arm . The airbrush should feel comfortable in your hand with your hand and arm relaxed .

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Controlling The Flow Of Paint

Airbrushes often come with a range of tip sizes like: fine, medium and course. Some of the cheaper brands can't be adjusted and some offer replacement tips as an optional extra. A lot of modelers stick with a medium tip for all but the most exacting work.

Two main factors influence the paint coverage. They are 1) the amount of paint being dispersed and 2) the distance between the airbrush tip and the work being painted. If you look again at the earlier diagram, you will see that the paint exits from the tip and expands into a cone shape pattern.

So, the amount of paint being released and the distance the airbrush is from the work affects the result. Another factor to consider is the amount of time the airbrush stays spraying in one location. The longer the airbrush stays in one place, the more paint that will end up on the object being painted.

To paint a fine line the airbrush needs to be held fairly close to the work and the paint flow rate must be low.

To cover a larger area, the needle needs to be pulled back to allow more paint to flow. The airbrush would also be held further back from the work.

To achieve a light spray, the airbrush would be held even further back with only a small amount of paint being allowed to flow.

Practice your techniques on some paper. Try creating some round dots, not splats but perfectly round uniform dots. This is difficult and you first attempts will look something like this. Keep going all the way across the paper slowly. Do several pages of these until you feel you have mastered round dots. Now do small lines straight across the page, making each line about 3 or 4 inches in length.

Now try linking the dots and lines together. Airbrush round dots all over your page in no particular pattern. Now connect all the dots with lines . Remember to keep the air on all the time as you airbrush a line from one dot to the next dot. Try and create straight lines from dot to the next dot without reshaping the dots as you go. The distance of the tip of your airbrush from your paper will have an effect on the paint you are spraying .

After you have mastered dots and lines try doing some shading. Position your airbrush several inches back from surface and spray a light dusting over the paper. Move from left to right and start shutting down paint flow as you move to the right edge of the paper. Follow through with air on only. Airbrushing is all about building up several thin layers so the objective in this exercise is to have even shading all the way across and down the page.

There should be no blobs of paint, or signs of stopping and starting, and there should be no obvious difference between each pass. The distance of your tip from the painting surface will make a big difference to the results you get.

Before you attempt to airbrush your train scenery or a precious model, I would recommend that you ALWAYS experiment on paper or a piece of wood first. You need to make sure no residue of water, cleaning solvent or paint still remain in the airbrush. You will also need to get a feel for how the paint will disperse depending on its thickness and the air pressure.

Spraying Techniques

The first important tip is to always start spraying before reaching the model and continue spraying after leaving the model. This will give a more even paint coverage on the model. It will also give you time to stop spraying if the paint splatters or the color or effect doesn't look right. Here is what I mean:

Cleaning Your Airbrush

An airbrush is a precision instrument and to function efficiently and reliably it must be keep in near-new condition. If it is left uncleaned it will clog up with dried paint residue and may become irreparable. Even with careful cleaning, paint deposits can build up in the paint cup and inside the airbrush. Every few weeks or months it may pay to carefully disassemble the airbrush and soak the metal parts in lacquer thinner to loosen any old paint that has built up. A paper towel or soft cloth is handy for drying the parts. A second soaking may be necessary to loosen really stubborn paint residue. If you unscrew the nozzle be careful not to jab yourself with the sharp needle inside the airbrush.

Oil Based Paints

Airbrush lacquer thinner can be used for cleaning oil paint from an airbrush. When you have finished painting simply pour any unused paint back into the bottle and spray the excess paint on a piece of old newspaper. The paint cup can then be wiped clean with a small soft cloth. The end of the airbrush and the paint cup can then be placed in a jar (or can) containing lacquer thinner. I usually slosh the end around in the lacquer thinner to loosen any oil paint that remains. I then pour the surplus thinner from the airbrush cup and partially refill the cup with a little clean thinner. I then spray the clean thinner into the jar of used thinner. All done!

Acrylic Paints

The same cleaning method can be used for acrylic paint, but if you are using acrylic paints, you may not want to use a solvent such as a lacquer thinner. Some people use isopropyl alcohol (from a drugstore) mixed with water for cleaning after using acrylic paints. A jar of warm water may be your preferred option, although using a laundry sink may be easiest (just remember to clean up the sink too).

If you are using a sink you can gently run warm water into the paint cup to flush out any remaining paint. One option is to hold your finger over the end of the airbrush (with the needle pulled back) and squirt some air into the airbrush. This results in a kind of “back-flush” which forces the remaining paint back into the paint cup to be washed away by the gently running warm water. (note: this method may not be suitable for some airbrush brands depending on the design of the airbrush).

Some people like to use a 50/50 mixture of water and Windex for soaking the airbrush when using acrylic paints.

The needle valve can then be used to open and close the airbrush tip until there is no further sign of any paint remaining. The paint cup can then be filled with water which can be blown through the airbrush.

The airbrush needs to be given a good blow through of air, a shake and a clean with a soft cloth to ensure that no surplus water remains inside or on the airbrush. If any water remains, it will mix with any new paint you add and and cause unwanted results.

Enjoy your airbrushing!

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© 2006 Robert Anderson, Market Leaders Ebooks, all rights reserved