GLOSSARY
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H
HALF-SHEET SANDER
A power tool with a flat, rectangular
pad to which a half sheet of sandpaper is clamped. Half-sheet sanders
work well on large, flat surfaces.
HARDENER
Additive (cross-linking agent, resin,
or other modifier) used to promote or control the hardening or curing
reaction of a coating or resin system.
HAZARD
A danger that may result in personal
injury or death when a substance or object is used in a particular quantity
or manner or a procedure is done without regard for safe working practices.
Hazards present in painting operations include toxic substances, materials
that can ignite and/or explode, electrocution, falls, confined spaces,
hand- and power-operated equipment, lead paint removal, etc.
HAZARDOUS SUBSTANCE
A substance that, by reason of being
explosive, flammable, poisonous, corrosive, oxidizing, or otherwise
harmful, is likely to cause death or injury when misused.
HEAT AGING
The deterioration of a coating, wallcovering,
or other material as a result of exposure to elevated temperatures.
HEAT GUN
A tool used to blow very hot air onto
a painted surface to soften the paint film for easy removal with a scraper.
A heat gun should be used with care; it can be a fire hazard when used
improperly.
HEAT RESISTANCE
The ability of a coating to resist deterioration
when exposed continuously or periodically to high temperatures at or
below a given level, which depends on the binder type and other coating
ingredients.
HEAT STRIPPING
Use of a heat gun to soften existing
paint film for removal by scraping.
HEATER
A heater is used to control the viscosity
of coating materials for plural-component, airless, and sometimes air
spraying systems. Heaters can be placed in the supply container, in
the supply hose (in-line), or both.
HEAVY-CENTERED SPRAY PATTERN
An uneven spray pattern having more coating
in the centre and less at the edges.
HEPA FILTER
An air filter that removes 99.97 percent
of all particles larger than 0.3 micron.
HEPA VACUUM
High-efficiency particulate air-filtered
vacuum designed to remove lead- contaminated dust.
HIDING PIGMENT
Pigment with a high refractive index
to give a coating the most hiding power. Rutile titanium dioxide, anatase
titanium dioxide, zinc sulphide, and zinc oxide are materials with high
refractive indices.
HIDING POWER
The ability of a coat of paint, which
has been properly applied, to hide a surface or a previous coating on
that surface.
HIGH BUILD COATING
A coating designed to be applied thicker
(usually 5 mils or more) than most paint films and thinner (about 30
mils or less) than most trowel-applied coatings.
HIGH EFFICIENCY PARTICULATE AIR (HEPA) FILTER
An air filter that removes 99.97 percent
of all particles larger than 0.3 micron.
HIGH FLASH (HI-FLASH) NAPHTHA
A hydrocarbon solvent mixture composed
primarily of aromatic compounds and having a flash point above 113 degrees
F.
HIGH GLOSS
The sheen on dry finish that is full
gloss.
HIGH SOLIDS COATING
A coating with considerably higher none
volatile matter (NVM) than conventional.
HIGH VOLUME-LOW PRESSURE SPRAYING
HVLP spraying uses a high volume of air
delivered at a low pressure to atomise paint into a lower velocity stream
than conventional air spraying. The resulting "soft" spray
does not bounce off the substrate or blow by it as readily as conventional
air spray does.
HOLIDAY
A spot on a painted surface that was
missed and not covered by one or more coats of paint.
HOLIDAY DETECTOR
An instrument using electric current
(low voltage, high voltage or AC electrostatic) to detect nicks, scrapes,
pinholes, or weak spots in a protective coating film.
HOT MELT APPLICATION
The application of a coating that has
been heated to reduce its viscosity. Hot melts can be applied by mop
or swab, by brush, roller, or by flow coating.
HOT SPOT
A spot in plaster that results from improper
mixing. If paint is applied over a hot spot, a chemical reaction causes
"burning," which damages the paint film. Hot spots must be
coated with primer before painting.
HOT SPRAYING
The spray application of a coating that
has been heated to reduce its viscosity.
HUE
The name of a colour, such as red, blue,
or orange.
HUMP JOINT
Raised joint caused by excessive application
of joint compound by hand or machine.
HVLP SPRAYING
HVLP (high volume-low pressure) spraying
uses a high volume of air delivered at a low pressure to atomise paint
into a lower velocity stream than conventional air spraying.
HYDRAULIC SPRAYING
A coating application system that uses
hydraulic pressure instead of air to atomise the paint. Atomisation
is achieved by forcing the paint at high pressure (2,000 to 3,000 p.s.i.)
through a spray nozzle with a small orifice (opening).
HYDROBLASTING
Directing jets of pressurized water against
a surface to remove paint and debris. Water jetting is typically classified
as either high-pressure (10,000 to 25,000 p.s.i.) or ultra high-pressure
(25,000 p.s.i. or greater).
HYDROCARBON SOLVENT
Aliphatic, aromatic, or cyclic (cycloparaffinic,
naphthenic) solvent consisting only of carbon and hydrogen atoms. Sometimes
the term hydrocarbon is used loosely (but incorrectly) to refer to any
organic compound.
HYDROLYSIS
The process of curing by reacting with
water either directly applied or obtained as vapour from the atmosphere.
