why the paint runs or sags down the wall when I spray
Runs and sags usually mean the wet coating cannot support the amount applied in that area. Too much material, slow gun movement, heavy overlap, inappropriate thinning or unsuitable application conditions can contribute.
Stop adding paint to the defect
Do not try to hide a fresh run with more spray. Follow the coating supplier’s method for correcting wet defects or allow the film to dry sufficiently for repair. Sanding or recoating too early can damage a larger area. Keep the gun safe and relieve pressure before changing the tip.
Check movement before changing equipment
- Move before triggering and release before stopping.
- Keep speed steady across the whole pass; avoid slowing near edges.
- Hold the gun square to the wall at the tip’s recommended distance.
- Keep overlap consistent. Corners can receive material from two directions and become overloaded.
Moving farther away is not a universal cure. Excessive distance can produce dry spray and overspray. Set a controlled working distance and adjust delivery to suit it.
we recommend you to practice with water before you spray the paint. more excercise, better the finishing.
Match tip flow to the surface
A smaller orifice generally delivers less material under comparable conditions, while a wider fan spreads delivery across a broader area. For example, changing 419 to 417 changes orifice size; changing 317 to 517 primarily changes nominal fan width within a conventional tip series. Neither change is automatically suitable: stay within the coating’s approved tip range and the pump’s capability.
A worn tip may apply more paint than expected. Check the tip, gasket and guard specification before replacing parts.
Check the coating and conditions
Verify thinning amount, mixing, product temperature, surface temperature and recoat interval. Excess reducer can alter sag resistance. A cold surface or application outside the permitted range can change drying behaviour. Do not mix in extra thickener or solvent without the manufacturer’s instruction.
Measure the film on a test area
Use the specified wet-film check and compare consumption against the expected coverage. Appearance alone does not show the film build. Several coats within the approved thickness and recoat limits are more controllable than one overloaded pass, but do not invent extra coats if the system requires a specific application.
After adjusting one factor, test again before returning to the wall. If the gun drips when released rather than during a pass, inspect the gun and needle by the approved service procedure; that is a different problem from sagging.
