Unsteady powder feed seen as a flickering or puffing stream in the plume and felt as uneven thickness and banded porosity in the coating. Causes include damp or clumping powder, a worn metering disc, low carrier gas, long or kinked hoses and a feeder hopper running low. Pulsing at a steady rhythm often matches the feeder disc rotation.
Plume is pulsing on a two-second beat, that's the feeder wheel, swap the disc before the next part.
Also heard as
- surging
- puffing
- powder pulsing
Related terms
Powder feeder
The hopper and metering unit that delivers a steady, measured flow of powder to the spray gun.
Carrier gas
The gas stream, usually argon, that carries powder from the feeder through the hose into the spray jet.
Plume
The visible jet of hot gas and glowing particles streaming from the spray gun toward the part.
Striping
Visible bands or ridges across a coating caused by uneven overlap between passes.