PAINT SPRAYERS

March 1, 2001
The gun and the spray tip of an airless paint sprayer have the most direct impact on the quality and efficiency of the job. They also can be the components

The gun and the spray tip of an airless paint sprayer have the most direct impact on the quality and efficiency of the job. They also can be the components given the least consideration by rental dealers.

The spray tip is the least understood of the two components. It helps determine the quality of the job. There are flat and reversible tips for airless paint sprayers as well as special tips designed for airless line stripers.

One of the first things to understand is how airless spray tips are sized. The industry standard is that the first digit stamped on the tip is half of the spray fan width when the tip is held 12 inches from the surface. For example, a 517 spray tip — five times two equals a 10-inch spray fan. The second set of digits identifies the diameter of the tip orifice measured in thousandths of an inch (the 517 a .017-inch-diameter orifice).

Although a few tip sizes are the most popular, it would be a mistake for rental dealers or customers to use just these as a guide. The most popular sizes are the .015 and .017 because the majority of rental airless pumps flow at a half-gallon per minute. With sprayers this size, capacity is the most significant determinant of tip orifice size. Some rental dealers and contractors with larger sprayers require larger tips in order to work at a speed their pumps can support. Moreover, customers applying lacquers, oil-base enamels, stains, sealers or other light coatings require smaller tips.

Abrasion and corrosion

Tip wear rate depends on the abrasiveness and corrosiveness of the material being sprayed along with the flow and pattern width. The number of gallons that wears the tip to the next larger size varies from a few gallons to 100 gallons. Usually, the cheaper the paint, the quicker the wear. Coatings that contain more abrasive solids result in faster wear.

Rental centers should replace worn tips as soon as they adversely affect spray pattern and pump performance. Many savvy paint contractors who spray high quantities of contractor-grade latex paint replace their tips every day. A rule of thumb is to replace each tip after five rentals.

Remind your customers to spray at the lowest pressure that will atomize their paint. It saves paint and money. Before painting, the spray pattern should be tested on cardboard. Set the pressure on the low side and raise it until the “tails” are gone and coverage is uniform. This reduces tip wear, prevents over-spray and gives the best finish.

Proper settings

Several major airless sprayer manufacturers have added solid-state pressure readouts to their sprayers. These readouts help customers adjust to the proper pressure setting for the material being sprayed. For example, lighter-viscosity fluids such as stains require spraying pressure to be 450 to 800 pounds per square inch, and latex, 1,700-2,200 psi. A number of paint manufacturers also list on their labels the proper spraying pressure for their product. The pressure readout also helps your maintenance department monitor machines' performance and speed up trouble-shooting.

Another important factor to consider is the flow capacity of the pump being used. If the tip is too large or worn, the sprayer won't be able to keep up, and the spray pressure will drop. It is also important to select a tip that is not too close to the maximum flow rate of the sprayer.

In addition, consider the coating to be applied. Coatings have variables such as water base, solvent base, percentage of solids, particle size (that must pass through the tip orifice) and atomization pressure. Another factor in tip selection is application requirements such as surface area thickness and the speed of the gun movement. To help select the proper tip size, see the Tip Selection Chart (right).

Remember, before renting your airless, don't forget the tip. Check it for wear and change it frequently to ensure your customer will get a professional paint-spraying job. Also be sure that when the unit is returned, the spray unit, gun and spray tip are cleaned. Once a standard check-in and check-out procedure is established, airless sprayers can become one of your most profitable rental items.

Airless Spray Tip Selection Chart

Coatings Coating Viscosity Filter Mesh Orifice Size Varnishes, lacquers light body 100 .009-.011 Sealers, clear shellac .009-.013 Transparent stain, water sealers .011-.013 Solid stain medium body 60-100 .013-.015 Exterior wall paints .015-.019 Interior wall paints .015-.017 Interior/exterior primers .017-.019 Commercial-grade architectural coatings, heavy body 60 .017-.021 Interior wall paints, " Interior wall primers " Dry fall, one-coat, primer finish paints .019-.023 Elastomerics extra heavy remove .021-.031 Pigmented waterproofers filter 021-.027 Blockfiller .025-.031 *The orifice sizes recommended are based on fan widths of 10-12 inches.

Information provided by Airlessco's rental division in Moorpark, Calif.

The RentSpray airless paint sprayer features a computerized pressure control that allows the unit to accommodate a wide range of coatings, Titan says. The unit features a diagnostic calculator that stores operating information, pressure and dead band. It is equipped with an anti-theft device, and its skid frame and low-ride models feature an exclusive “easy out” live siphon swivel for faster pail changes and easy cleaning.
800/557-1076

Weighing 24 pounds, the EP 2105 is 30 percent lighter than other DC motor piston pumps, SprayTech says. At .4 gallons per minute and 3,000 pounds per square inch, the unit is ideal for residential and commercial jobs and spray coatings from lacquers and stains to latex.
www.spraytechinc.com
800/443-4500

ASM's Rental-Zip System for airless sprayers allows rental centers to sell the spray tip and wear part with each rental at a price renters will pay for consumable wear parts, according to the company. With the system, stores can replace spray guns, not rebuild them.
800/854-4025

The Marksman line from J.S. & Sons offers five models of airless sprayers - the 0-19, 0-20, 0-21 (pictured), 0-26 and 0-29. All units are designed to have minimal downtime, according to the manufacturer, and are available in three cart configurations: an upright version for contractors, skid-mounted for homeowners and a lowboy design with a collapsible handle.
800/488-4555

H.E.R.O. Industries' H2K line of airless paint sprayers includes models 3819S (pictured), 3819C, 5523S and 5523C. Powered by a .6-horsepower electric motor, the 3819S has an output of up to .38 gallons per minute, a working pressure of up to 3,000 pounds per square inch and a maximum tip size of .019.
www.hero.ca
604/420-6543

The Airlessco Rev-Tip is a reversible airless paint spray tip. According to the manufacturer, the carbide unit will not leak or splash back and is compatible with all solvents. The hand-tighten nut is available in F and G threads, and a single metal seal sprays all coatings.
www.airlessco.com
800/223-8213

Graco's new line of Ultra Max electric airless sprayers features an AutoClean system that reverse-flushes the sprayer, hoses, gun, tip and filters. After the reverse flushing, the system shuts down automatically. With a maximum working pressure up to 3,300 pounds per square inch and 300 feet of hose, the unit can spray high-viscosity coatings. Other features include a microprocessor-driven SmartControl that digitally displays spray pressure, gallons used, the AutoClean timer and error codes; an Easy-Out manifold filter that cleans from the inside out; and an Endurance piston pump.
www.graco.com
800/690-2894

Wieburg Enterprises is a paint sprayer distributor that offers products from popular manufacturers, including Graco's 395ST Pro electronic airless sprayer. Designed for residential and maintenance painting with stains, lacquers and latex paints, the unit provides a maximum fluid pressure of 3,000 pounds per square inch with a delivery of 0.38 gallons per minute. It supports tips up to 0.19 and sprays materials through 300-foot hose. The 395ST also features a .5-horsepower Dura Pro DC motor, an Endurance E piston pump and the SmartControl process for spray pressure consistency.
800/937-7729