Piston Paint Sprayers

How a piston pump works

Inside a piston sprayer the motor drives a piston in a cylinder: it draws paint through the foot valve and forces it into the hose at roughly 200–230 bar; the tip then breaks that stream into a mist with no compressed air, which is why the method is called airless. With no diaphragm to flex, pressure holds steady even when the coating is thick or chilled to a few degrees.

Contractor-grade piston units deliver about 2 to over 8 l/min, which works out at 200–600 m² sprayed per hour, with reserve to run two guns from one pump. Piston packings, ball valves and filters are replaceable, so with regular flushing the machine works season after season.

Piston or membrane — how to decide

The deciding factors are the material and the length of the working day, not price: a piston pump suits dense coatings and long runs, while a membrane (diaphragm) unit is simpler to look after on water-based paint.

In short: façades, steel structures, industrial buildings and solvent-based coatings call for a piston machine, while interiors, latex paints and occasional use are covered by a membrane sprayer. Skim coats and jointing compounds are handled by heavy-duty spackling sprayers.

Matching tip and output to the material

Tip choice follows the viscosity of the coating, not the size of the wall. In a three-digit tip code the first digit doubled gives the fan width in inches from 30 cm, and the last two give the orifice in thousandths of an inch: 517 means roughly a 10" fan and a 0.017" orifice.

• Lacquers, stains, thin primers — tips 0.009–0.013", about 2 l/min is enough.
• Latex and acrylic interior paints — tips 0.015–0.019", consumption around 0.25 l per m².
• Façade, silicone and anti-corrosion paints — tips 0.021–0.027", pump from 4 l/min up.
• Coarse-textured compounds — tips from 0.027" up, 3/8" hose past 30 m.

Tips, filters and guns sit in paint sprayer accessories; road lines are laid with line stripers — the same pump on a wheeled frame.

FAQ — piston paint sprayers