Particle
Smallest possible part.
Particle Size
The average diameter / size of particles supplied as a powder coating, following the grinding process.
Pass
The motion of a spray gun in one direction only.
Passivation
Conversion of a metal surface to a less reactive state. A process to reduce corrosion rate of metal surfaces.
pH Value
Measurement of acidity or alkalinity. pH 7 is neutral, Values greater than 7 are alkali less than 7 acid.
Phosphate
To form a thin film of inert phosphate on the metal surface. Process to reduce the rate of corrosion.
Pigment
Particles in a powder coating formulation that provides the colour, corrosion resistance and other properties.
Pinholes
Formation of small holes through to the substrate. The appearance of fine pimply defects in a cured film.
Pinpoint Diffuser
Powder gun tip, which yields a concentrated pattern.
Plastic
One of many high polymeric substances, including both natural and synthetic rubber. At some stage in its manufacture or refinement every plastic is capable of flowing under heat and pressure to form its final shape.
Plastisol
Film former containing resin and plasticiser with no solvents that forms a tough resistant thermoplastic coating.
Polyester
A resin or powder containing the grouping R-COOC-R. The powder having excellent resistance to UV light.
Polyethylene
Resin with the formulation CH2CH2 used in thick film thermoplastic powder coatings.
Polymers
Poly = many: mer = units, Polymers are very large molecules built up by the combination of many smaller molecules, often having many thousand molecules.
Polymerisation
Chemical reaction in which smaller molecules combine to form a high molecular weight polymer.
Polypropylene
One of many polyolefin thermoplastics. Usually in exterior quality thermoplastic powder coating.
PVC
Polyvinyl Chloride. Synthetic resin used in both liquid and thermoplastic powder systems.
Porosity
Degree of integrity or continuity. A porous material will allow liquid or air to pass through.
Post Cure
Heating of an object after application of the powder coating.
Post Heat
Heating of an object after application of the powder coating.
Pourability
The ability of a dry powder to flow uniformly or to be continuously poured from container at a steady flow.
Powder Booth
An enclosure used for containment of powder coatings during the spray application.
Powder Particle
The smallest single piece that results after grinding powder chip.
Powder Segregation
Stratification. Separation of powder particles (due to size) during the spray operation and recovery system. Due mainly to the forces of gravity, speed and electrostatic deposition. Resulting effect can be changes in gloss or changes in the degree of "orange Peel".
Preheat
Heating the component before the application of the powder coating.
Pressure
Force per unit area relative to atmospheric pressure. Usually expressed in psi (pounds per square inch).
Pressure Drop
Loss in pressure usually due to length or diameter of piping or hose. Can be caused by blocked filters.
Pressure Gauge
A gauge to determine the delivered pressure of a gas or fluid.
Pre-treatment
The preparation of a part (component / substrate) prior to the coating to improve adhesion and corrosion resistance.
Primer
A type of coating applied to the substrate surface to improve adhesion of a subsequent topcoat. To improve corrosion resistance, hiding power, surface smoothness.
Profile Depth
Average distance between the top and bottom of valleys on a surface.
PSD
Particle Size Distribution. The range of particle sizes in the manufactured powder coating.
Purging
Cleaning one colour or powder formulation from all areas that come in contact with the powder coating before introducing a new powder.