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Maintaining Your Sprayers

The piston also needs a little TLC. Bill Drozd, technical support manager at ITW Industrial Finishing, recommended leaving the piston in the upstroke when you shut off your pump. “If it dries, it’s easier for it to move down than up,” he says.

The cup in which the piston moves can be oiled with a specially designed lubricant that prevents paint from drying on the piston. The trigger, control valves, and springs of the spray gun should also be occasionally lubricated.

Many companies sell some kind of a flush product that coats the internal parts of your sprayer and protects them from corrosion or rust. The liquid may also help keep the piston and seals lubed, pliable and free from encrusted latex paint. Water will suffice from day to day, but if you’re letting the sprayer sit even for a weekend, a protective liquid ought to be considered.

Tune-ups and replacements
Paint is abrasive, and your sprayer’s parts will degenerate with use. So be prepared to replace them.

The round polyethylene seals are called “packing,” and replacing them is known as “repacking.”

Contractors who use small sprayers, those that turn out under a gallon per minute, should expect to repack after several hundred gallons of use, says Tonnessen of Titan Tool. The piston, inlet valve and outlet valve may need to be replaced every two repackings, he says. Some sprayers come with valves that can be reversed, exposing a fresh surface to wear. Typically, a spray tip will need to be replaced after 100 gallons, he says.

Mike Jane, service technician with Spraytech, says to trust your judgment — your packings and piston are fine until you see symptoms of poor performance. Packings don’t need to be replaced until fluid leaks from the top of the fluid section, he says.

The same principle holds true for spray tips. “The spray gets heavier as the tip wears out because the orifice is getting larger,” Drozd says.

How much and what kind of material you spray will affect the life of your sprayer’s parts. If the gun starts to spit or dribble, it may also be wearing out.

Finally, the fluid lines should be checked every job for safety, but only need to be replaced if they are worn to the core, cracked or abused. “Hoses are very durable,” Jane says. “It takes a huge amount of abuse to wear them down to the core. Mainly hose replacement is because it was being abused by the contractor.”

Long-term storage
If the machine is going to be stored, a little long-term preparation is in order. Do a final flush with mineral spirits before storage, perhaps adding 30-weight oil to the mix.

If you’re bringing a machine out of storage after stowing it properly, you won’t have to do much. Just purge it with water before introducing any water-based material. Use the flushing liquid to check the sprayer’s ability to prime, build pressure and shoot spray. If you’re going to spray an oil-based material and solvent is already in the system, you can skip the preliminary flush.

Lubricate the piston cup and check the filters just to be sure. Finally, spray a test pattern on cardboard to make sure your equipment is performing to your standards.