Technical data

C
CASE HARDENING — The formation of a hardened top
surface with a soft underbody. Proper relative humidity
conditions within the drying room will assist in eliminating
this condition.
CATALYST — A substance which changes the rate of a
chemical reaction without itself undergoing permanent
change in its composition.
CHALKING — Deterioration of an organic coating upon
exposure that results in a powdery, chalky residue on a
painted surface.
CHECKING — Slight breaks in the film which do not
penetrate to the underlying surface. It occurs when lacquer
coats are applied too heavily or without sufficient time
allowed for drying between coats.
COBWEBBING — Filaments of paint which appear as
cobwebs instead of fine droplets.
COLLOID — A very finely divided (but not molecular)
dispersion of a solid in a liquid. Colloidal dispersions do not
settle and the particles are too small to be observed by
ordinary microscope.
CONSISTENCY — Consistency is another word for vis-
cosity of a wet material. The term may also be applied to the
resistance to deformation of a cured film.
CONVERTER — A substance which causes a resin to
polymerize or cure. Polyamides and amines are two ex-
amples of epoxy converters.
COVERAGE — The surface area which can be coated with
a given volume of coating applied at a given film thickness.
Coverage is usually expressed in square feet per gallon at
one mil dry film thickness. Coverage is not related to hiding
power.
CRACKING — Cracking occurs when the various compo-
nents of a lacquer are not blended or mixed properly, or
when coatings not compatible with one another are used
together.
CRATERING — A defect in a coating resulting in craters
or fish eyes. Most often caused by the presence of grease,
oil, silicone polishes or other similar contaminants on the
surface.
CRAWLING — The reverse of crazing, that is, a more
flexible coating is applied over a hard or brittle film.
CRAZING — When lacquer films expand and contract, a
series of fine hair line cracks (crazing) results. Crazing
frequently occurs when a very heavily pigmented surface
coat is applied over a more flexible undercoating. The
elastic coating of lower filler content will expand and
contract more easily than the heavily pigmented coating.
CRYSTAL LACQUERS — A decorative finish which is
achieved by re-cyrstallization of dissolved lacquer bases. It
occurs after the thinners have evaporated. Pearl essence or
mother of pearl finishes may be produced in this fashion.
CRYSTALLINE FINISH — A crystalline like, decorative
finish is accomplished by using certain gas checking oils
which on drying produce the pattern.
CURDLING — Curdling usually occurs when a high
evaporative but weak solvency thinner is used with a
lacquer or enamel. Control of solvency and evaporation rate
will prevent curdling.
D
DECAL — A plastic film with an adhesive on one side that
adheres to glass, wood, metal, etc, that transfers decorative
pictures or designs printed on the specially prepared film to
the surface.
DILUENT — A thinner blended with an organic coating
mixture to increase its volume and/or reduce its viscosity.
DISPERSION — An intimate mixture of finely divided
solid particles in a liquid substance. Paints are dispersions of
pigments in a vehicle.
DOUBLE COAT — A double application of paint. This
does not mean two consecutive passes of the spray gun. One
coat is applied by a double or cross pass of the gun followed
by a second similar application after the first coat has set up.
DRIER — A catalytic material which when added to a
drying oil or drying oil modified coating accelerates the rate
of drying. A substance which speeds the reaction of a binder
with oxygen. Naphthenates of cobalt and manganese are
common driers.
DRYING OIL — An oil which readily absorbs oxygen
from the air to form a durable film.
TO 1-1-8
Glossary 2