Why do I get streaks or bands in my spray pattern
Heavy lines at the edges of a test fan often indicate incomplete atomisation; stripes on the finished wall may instead come from inconsistent passes or overlap. Test the spray pattern separately before changing the machine settings.
Identify which pattern you are seeing
| Symptom | Start here |
|---|---|
| Two heavy tails on a single test pass | Working pressure, tip compatibility and supply restrictions |
| Uneven or one-sided fan | Partial blockage, damaged tip or incorrect installation |
| Regular stripes across a painted wall | Distance, overlap, movement and wet-edge control |
| Pattern repeatedly grows and shrinks | Supply interruption, pump cycling or pressure-control issue |
Use pressure carefully
With an approved tip and material, increase pressure only within the equipment and coating limits until a suitable fan is obtained. Use the lowest effective setting. Maximum pressure is not a remedy for every poor pattern, and some low-pressure tips are designed for different working conditions.
Mostly increasing the pressure will solve the problem quickly. How many bar / psi pressure is needed will depends on which type of spray nozzle you use.
The high pressure airless spray nozzle requires minimum 140bar spraying pressure to get a nice finish, while low pressure tip (green color handle) needs only 100-120bar pressure.
So contact us by email dp@dpairless.com to check which pressure you need or what problem you got, we can confirm to you if you set the right pressure.
If more pressure does not solve it
- Relieve pressure and isolate the machine before cleaning. Check the tip, inlet strainer and applicable pump and gun filters.
- Confirm the coating’s recommended orifice and the sprayer’s supported tip size. A worn opening can demand more flow than the pump supplies.
- Inspect the suction supply for air leaks, low paint level or restricted feed.
- Check whether hose length, bore and material temperature have changed the pressure loss.
A smaller approved orifice may reduce demand, but it must remain suitable for the coating. A larger tip is not a general fix for pressure fluctuation. Do not remove required filtration or thin beyond the coating instructions.
If the test fan is good but the wall is striped
Keep the gun perpendicular to the surface and maintain a consistent distance and speed. Overlap uniformly and avoid wrist arcs. Work in a sequence that maintains the specified wet edge. Check lighting and surface texture as well as the coating’s back-rolling requirements.
Mechanical versus electronic pressure control
Control design can affect operation, but an electronic controller does not guarantee a flawless finish. Actual pressure stability depends on the individual machine, tip, material and pump condition. Diagnose the measured behaviour instead of using a universal pressure-drop range.
Compare the electric airless sprayer range only after establishing your material and output requirements.
