Pinholing
A defect caused by small holes in the dry paint film allowing the underlying colour to show through or the passage of water. (see Cratering).
Pitting
Shallow depressions, holes caused by the corrosion of steel or preparation by chipping hammers or mechanical chisels used to remove mill scale. Also Pock Marking.
Polychromatic
A coating which has a metallic appearance, produced by applying paints or lacquers containing polished particles of metals such as aluminum, bronze or copper.
Polyester Resin
Used in a wide range of conventional air-drying products is oil free and used in glass fibre structural components such as boat building.
Polymer
The product of polymerisation: large molecules, (see Homopolymer and copolymer) used in the manufacture of plastic products.
Polyurethane Resin:
Synthetic resins which are often used in two pack products with a poly-isocyanate used as the curing agent – or modified with alkyd resins to produce a hard wearing finish.
Polyvinyl Acetate (P.V.A.)
Synthetic resin commonly used as the binder in the manufacture of emulsion paints.