Selecting The Right Air Brush
There Are Different Brushes For Different Jobs, Along With...
Different Mixing Procedures & Important Accessories
by Larry Lyles
My first thought when I decided to do a report on air brushes was that I really didn't have much to report on. Old car guys use spray guns. They may use three or four different spray guns, but mainly they only use spray guns. Then I opened the cabinet to retrieve my air brush, I thought rubbing it against my forehead might inspire me, and suddenly I realized I owned no less than four, count 'em, four, air brushes. I'm an old car guy. What did I need with four air brushes?
That was about the time I realized I treat air brushes the same way I treat spray guns, by designating each one to a special purpose.
For example, I use one of the air brushes exclusively to spray small parts. Another one is for spraying things like wide stripes that require a large storage of paint, while another is use exclusively for those intricate, detailed sort of things like flames and pin stripes. The last one, well, it's new and I have it just because it is different from the other air brushes and I like its approach to old school, set in their ways, car guys like me.
Going Brush by Brush
Okay, with all these air brushes I must have
something to report on.
Let's take a closer look at all four.
This suction type air brush comes with 20cc and 50cc push-on cups, an extra paint storage bottle, five feet of air line and a holder.
If I were picking up an air brush for the first time this would be the air brush of choice. It is a very good all around air brush and the best place to begin when getting started with seeing what an air brush can do for you. When do I reach for this particular air brush? I primarily use it to spray small parts that require a quality finish.
I also like the control this air brush offers when it comes to spraying in and around parts such as door hinges. Over spray is kept to a minimum and the chances of getting a run are almost zero.
With an air brush like this I can mix enough base color to spray all four hinges, load the 50cc cup and never have to refill before the job is done.
Is just what the name implies, a gravity feed air brush. Yep, that means the cup, in this case a 5cc cup, is mounted on top of the air brush. Well, actually the cup is side mounted but it does sit above the body of the air brush, which makes it gravity feed.
Why is the cup side mounted? Mounting the cup on the side of the brush allows the cup to be tilted so that no matter what angle you need to position the air brush the cup can be rotated to always stay erect and level. The result is a spill proof cup.
Where am I going to use this air brush? Again, we're talking working with small parts. The difference between this brush and the suction brush discussed earlier is its ability to reach into those tighter areas. I wouldn't have a problem with crawling inside a car with this brush in hand to take care of minor touch up needs around the dash, steering wheel, steering column, or console.
A professional, graphics quality, gravity feed air brush. Photo 3. It comes with a 0.3mm fluid nozzle and a top mounted 5cc cup. This is the gun I pick up when I need to lay out pin stripes or detailed graphics. The spray is finely atomized and in my opinion perfect for shading flames or adding detail to any other graphics you might want gracing your ride
This gravity feed air brush comes with a 22cc and a 17cc cup. What really sets this gun apart from the others is the spray gun style trigger instead of the top mounted finger trigger common to most other air brushes. For guys like me who spend a lot of time with a spray gun in their hand the trigger air brush feels more natural in hand and doesn't require that mental shift to move from trigger squeeze to button press mode when using the gun.
So which gun is right for you? If you plan to use your air brush for spraying small parts only I would go with # 11611 Bottle Feed Air Brush. The large bottle means fewer reloads and less time mixing paint.
If your plan calls for spraying the occasion small part or laying out a flame or two I would opt for the # 11610 Gravity Feed Air Brush. The paint cup is smaller, 5cc, but the sleek design of the gun will offer better control and higher quality of the finish.
If your plan calls for becoming the next great air brush artist then # 12795 Professional Graphics Air Brush is the gun for you.
Finally, if having a trigger to squeeze is your thing, # 11612 Trigger-Style Air Brush is the perfect air brush.
Some Things You Should Know
Forget at least part of what you know about paint mixing because normal paint mixing ratios just won't work with an air brush. For example, a typical gravity feed HVLP spray gun uses a 1.3mm spray nozzle to spray base coat colors and clear coats. A typical air brush will have a 0.4 or 0.3mm spray nozzle. Refinishing products mixed to spray through a 1.3mm spray nozzle simply won't pass through a 0.4 or 0.3mm nozzle. The mixture is too thick. The solution is to mix the color or clear coat product per the manufacturer's P Sheets then further reduce the mixture by up to 75%.
Yep, that's what I said, 75%. It's almost like spraying water that has been thinned down with even more water. Won't you get runs? It is very possible. You are working with an extremely thin mixture. But don't forget, the control an air brush offers allows you to apply almost no paint at all and a lot of air, or plenty of paint and still a lot of air and that helps keep runs to a minimum. A tip here is to use faster drying reducers to prevent runs.
What has gone wrong if you get large droplets of paint from the air brush or the brush tends to splatter? You didn't follow my rule and reduce the mixture by 75%.
The next consideration has to be usage. I've already given you a few good ideas on how to select the right air brush for your specific needs, but once you have the correct air brush you have to consider how it is going to be used.
Are you thinking of adding a thin stripe along the length of your ride, or flames that extend from front to rear? If so you need to consider the length of hose needed. Air brush hoses are commonly available in 5, 6 and 9 foot lengths. Even 9 feet won't stretch from one end of a ride to the other so maybe more than one air hose is in order.
Now you have to think about how to get air moving through that hose. I actually have a permanently fixed and dedicated outlet for air brush use. The air is regulated down to the required 15 psi at the outlet and the set up works great as long as I'm working close to the outlet. If a car is sitting 30 feet away in another part of the shop the outlet is pretty much useless. When that happens I need a dependable, portable air brush compressor.
Air brush compressors come in two types, with and without a holding tank. The Eastwood # 11607 compressor features a 1/8 hp motor and delivers up to 50 psi without a tank. The Eastwood # 11609 compressor comes with a tank and features a 1/6 hp motor that delivers up to 60 psi. Which one is best? Again, it comes down to what you plan to do with the air brush. If you are mainly concerned with spraying small parts and laying out the occasional flame job the # 11607 compressor without the tank is perfect.
If your plans call for some serious graphic work where absolute precision is necessary opt for the # 11609 compressor with a tank. Having the tank to draw compressed air from eliminates the possibility of pressure pulses as it delivers a constant steady stream of compressed air to the air brush at all times.
Both compressors should be used with the Eastwood # 11608 filter/regulator to insure the air supply is clean and can be easily regulated down to needed 15 psi at the air brush.
Need to spray a door jamb? Using an air brush instead of a spray gun will result in a reduced build up of paint or clear along any tape line edge needed to stop over spray. Speaking of spraying clear coats through an air brush, the over reduced mixture required for spraying means applying up to five coats of clear to equal two coats sprayed from a full sized HVLP spray gun.
Practice results in perfection. Using an air brush is no different from spraying with a full sized HVLP spray gun in that practice always makes you a better painter. Like full sized spray guns, air brushes have their own little quirks that can only be learned through use. Black and white base coat colors are relatively inexpensive and will help you achieve a recognition of how shading and coloring can make or break your masterpiece.
Of course good help is always appreciated so if your plan calls for detailed graphics don't hesitate to check out the huge variety of instructional DVD's out there. Talking about how something is done is one thing, seeing it happen is quite another.
Then there are stencils. Way back when I first attempted air brushing stencils were prize possessions. They were all hand cut and easily ruined.
Today, air brush stencils of all types, sizes, and shapes are available from many sources. Laying out traditional flames no longer requires a steady hand or an artistic eye. Just select the stencil that suits your needs and with a little practice you can crank out professional results that will make your beer drinking buddies green with jealousy.
This article was published in the October
2007 issue of
Auto Restorer Magazine by Larry Lyles