Particles below the bottom of a powder's specified cut. Fines overheat or vaporize in the jet, stick to nozzles, injectors and barrels and break loose as spits, and they make powder clump and flow unevenly. Specs usually cap the fraction under the lower size, and powders that have been recycled, crushed in a feeder or stored damp tend to gain fines.
This lot is loaded with fines, it's coating the injector every ten minutes, send a sample out for sizing.
Also heard as
- undersize
Related terms
Cut
Shop word for a powder's particle size range, such as minus 45 plus 15 micrometers.
Spitting
A gun shedding blobs of molten buildup into the coating, leaving lumps known as spits.
Feedstock
The raw coating material fed into a thermal spray gun, as powder, wire, rod, cord or liquid suspension.
Agglomerated and sintered
Describes powder made by spray drying fine particles into balls, then sintering them to give them strength.
Same word, different worlds
The smallest particles in a powder, roughly under 10 microns, which fluidize, charge and recycle poorly.
Refractories & Furnace LiningsSmallest particle fraction of a refractory mix, which fills the gaps between coarse grains and forms the bond.
Paper Optics & TestingFiber fragments and small particles that pass a fine screen and have an outsized effect on sheet optics.
Asphalt PavingThe dust-sized part of the aggregate passing the No. 200 sieve, which stiffens the binder into a mastic.