Category:Spraying Notes


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The keys to a successful painting project are the right person, the right products and the right tools being utilized for maximum effect. Many artists and decorative artists have shied away from spray equipment for fear of the learning curve and perceived start up cost. However, those that do take the time to venture into spraying soon realize the benefits gained in regard to quality and speed, both of which tend to mean money in their pockets.

The goal of this document is to remove some of the confusion surrounding spraying and provide the information necessary to make the right choices early on, instead of learning the hard way by costly trial and error.


Paint/Coating Properties

Figure 4: Quick-release counters allow for fast, tool-less disconnection. Adjust air pressure on the compressor first, but the actual pressure reading is nearest the gun.

What you want to spray should be the first factor in deciding which equipment you need. Fluid products are measured using viscosity cups, which are like ladles that reveal the rate of flow through a specifically sized hole in the bottom of the cup. This is critical knowledge when trying to achieve flawlessly smooth topcoats and using higher end spray equipment. Also, don’t assume thick products cannot be sprayed. They might not work great in conventional or HVLP systems, but Airless and texture sprayers can handle heavier products with ease.

Project Needs

The kind of gun to use, or even if spraying is the right choice for a particular job is also an important consideration. If you spend hours prepping a room for 20 minutes worth of spraying, then it probably wasn’t worth the added time, unless of course the coating must be brush-stroke free and perfect. If you need to spray 50 cabinet doors, then using a small, 4 ounce cup sized touch-up gun isn’t as effective as using a larger gun with a quart-sized color cup. Do the math of time and cost of purchasing new equipment (and learning how to use it) to see the value is there.


There are good conventional spray guns to be had for as little as $30 that work just fine for many projects. But don’t forget you still need a compressor, and air hoses and connectors, and usually a good moisture trap and pressure regulator. If you decide you need a better or different gun for an upcoming project, see if the other parts you already have can be used with a new system. Why buy an all in one gun with its own air source if you already have a compressor? Just remember that equipment cost should not be the only factor. An expensive gun might be the best one for your profession and offset the cost of having to sub-contract a house painter because you can now do that work yourself.

Compressors/Air Sources

Figure 5: Oil-less air compressor.

The kind of spray gun you decide will dictate what your air source will be. Some guns have their own air source. Others require an air compressor. If you need a compressor, try to find ones that have a large air tank, which is the reservoir for the air pressure to build up in during spraying. A large tank makes the compressor bulky, but it also isn’t constantly running and making a lot of noise either. Get long hoses too. They allow for more freedom of movement and also mean you can put the compressor in an adjacent room while you work in relative silence.

Figure 6: Moisture trap and air pressure regulator.

When using long hoses, or coupled hoses, realize the pressure drops from the compressor to the spray gun. If the spray gun doesn’t have its own pressure gauge and knob, then attach one (better yet is one with an air cleaner/moisture trap) and then a short hose to the spray equipment. Appropriate pressure is very important to good spraying.

Refer to the diagram for a complete system from gun to compressor. If you are working in an area with limited access to electricity, CO2 tanks may be an option. Welding supply companies rent and fill air tanks, and an inert gas like CO2 (Carbon Dioxide) can provide a clean, quiet air souce. This is often limited for smaller projects such as airbrushing through stencils and not the best use for larger areas.

Masks, Respirators, Suits

Figure 7: Always use Niosh-approved respirators when spraying!

Regardless of what you want to spray, personal protection is of paramount concern. Never assume what you are spraying is safe for you to breathe, even if it says it’s non-toxic, green, or natural. Nuisance dust, solvents, airborne pigments and binders are not things to breathe on a frequent basis. Get educated about what you are working with (Material Safety Data Sheets or MSDS must be provided by paint companies upon request). Go to professional painting stores and learn what kinds of spray masks, respirators, painting suits, and gloves they offer and what they are designed to be used with.

Clean your equipment after EVERY use!

Don’t make this costly rookie mistake with whatever equipment you buy. Always clean your spray gun really well. You may be tired, hungry, and late, but if you don’t clean your gun immediately after use, it will not work properly for the next project. Use lots of water to flush out waterborne products. Use a strong enough solvent to get all of the dried stuff out of the lines. Wipe off needles and clean the nozzle air ports. Lube every moving part you can get to with safe lubricants that won’t cause fish-eyes or other surface defects in the paint. This is the best way to protect your investment.


Spraying doesn’t have to be confusing and once you get used to your equipment it can be a lot of fun. Take some time to practice on smaller shop projects or just get some large cardboard or drywall sheets and practice. You will receive what you put into this process.


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