- Training & Events
|Glossary of Terms|
Tape Adhesion –Test used to check for adhesion of a coating to a surface. (ASTM Test D3359)
TDS – Total desolved solids, a measurement of the solids content of water in parts per million (ppm).
Technical Data Sheet – (TDS) – A document provided by a supplier that details the properties and expected performance of a material. Also known as Product Data Sheet.
Telegraphing – Phenomenon that occurs when a surface defect on an uncoated part is visible in the cured powder after the coating is applied.
TGIC – Triglycidyl Isocyanurate, a common crosslinker for carboxyl polyester resins.
Theoretical Coverage – The capacity of a given mass of a specific powder to coat, in a cured state, an area of substrate at a determined film thickness.
Thermocouple – A pair of dissimilar metal wires that generate an electric force at the point of connection which varies in proportion to temperature.
Thermoplastic – A powder coating which will repeatedly melt when subjected to heat and solidify when cooled. Typical examples are vinyls (PVC), nylons, and polyolefins.
Thermosetting – Powder coating chemistry that undergoes an irreversible chemical change during thermal cure. Examples are: epoxy, polyurethane, acrylic.
Threshold Limit Value (TLV) – The concentration of a compound that a worker can be exposed to day-to-day without experiencing any adverse effects. TLV’s are established by the ACGIH.
Throughput – The production output of a system at a given line speed using a predetermined part density or hang pattern.
Time Weighted Average (TWA) – The legal limit of exposure of a chemical measured as average exposure over an eight hour period of time. TWA’s are established by OSHA and are used to define Permissible Exposure Levels (PEL).
TLV – See Threshold Limit Value.
Tooth – Profile. Mechanical anchorage. Surface roughness.
Totes – Large containers for shipping bulk powder coatings.
Toxic – Poisonous.
Toxicity – Degree of poisonousness or harmfulness.
Transfer Efficiency – The ratio of the powder deposited compared to the amount directed at the part to be coated.
Transformer, Pneumatic – Device used for regu lation of pressure in, and removal of moisture from, an air supply line.
Tribocharging – A method to impart electrostatic charge on a powder coating by the friction or contact of the powder with a material of dissimilar dielectric constant.
Triglycidyl Isocyanurate (TGIC) – A tri- functional epoxide compound that is commonly used as a crosslinker for carboxyl polyester resins.
Triggering – Intermittent squeezing and releasing of a spray gun trigger, or turning them on and off intermittently for some systems.
Turbulent Flow – Air currents within a spray booth that may be strong enough to negatively affect the application of powder. Good transfer efficiency is dependent on laminar air flow.
TWA – See Time Weighted Average.
Two–stage Compressors – Compressors in which compression from initial to final pressure is completed in two distinct steps or stages.
Ultraviolet Radiation – Light energy having a wave length of about 0.4 to 80 milimicrons. Such energy can break certain chemical bonds and contribute to the fading and wearing away of coatings.
Underatomized – Not enough atomizing air in ratio to supply air, resulting in a spray pattern that surges and is not fine enough for good charging efficiency.
Undercured – A coating that has not had enough exposure to the combination of heat and time to completely cure.
Upper Explosive Limit – Concentration of solvent vapor or coating powder particles in air above which the mixture will not explode if ignited.
Urethane – The product of the reaction between a hydroxyl functional compound and an isocyanate. Hydroxyl polyester resins cured with blocked isocyanate curing agents are commonly referred to as urethane or polyurethane powder coatings.
UV Flame Detection System – A device that senses the UV light emission cause by an ignition source. In powder coating application systems these devices are used to shut down the spray process when a spark is detected.
UV Flame Detection System – A device that senses UV light in a powder booth and shut the equipment off when it detects a spark.
Valve, Check – Direction control valve that allows air to pass in only one direction.
Valve, Flow Control – Valve whose primary func tion is to control flow rate.
Valve, Shut–off – Valve that operates fully open or fully closed.
Valve, Throttling – Valve used to regulate the pressure/flow of solutions in the washer.
Velometer – Device to measure the speed of air in feet per minute.
Venturi – A constricted throat in a powder pump that uses compressed air to lift and transport powder from the feed hopper to the application equipment device, from the bulk feeder to the feed hopper, from the cartridge module to the feed hopper, etc.
Vertical Zoning – Triggering only the guns needed to coat a given part length to reduce overspray when a conveyor is loaded with parts of various lengths. Multiple photo–eye inputs can be used to control which guns are used on any given part.
Vestibule – Small entrance hall to pretreatment washer, powder booth, or oven.
Vibratory Box Feeder – A device allowing the powder to be pumped directly from the box container utilizing vibration to keep powder moving.
Vibratory Sieve – See Sieve, Vibratory.
Vinyl – A popular name for thermoplastic polyvinylchloride (PVC) materials.
Vinyl Coating – A coating in which the major portion of the binder is a vinyl resin.
Vinyl Copolymer – Resins produced by copoly– merizing vinyl monomers such as vinyl acetate and vinyl chloride.
Vinyl Resin – Synthetic resins made from vinyl compounds.
Virgin Powder – Unsprayed powder as opposed to sprayed or reclaimed powder.
VOC – See Volatile Organic Compound.
Volatile Content – The quantity, expressed as a weight percent of the powder, which is lost under specified conditions of temperature and time.
Volatile Organic Compound (VOC) – Hydrocarbon chemicals that can evaporate into the atmosphere and are recognized by the US EPA as contributors to photochemical smog. VOC’s are commonly emitted from solventborne paints.
Voltage Tester – Instrument used to measure voltage output at the corona tip of an electrostatic powder spray gun.
Voltmeter – Instrument used to measure poten- tial differences in volts.
Volume Resistivity – Resistance in ohms per unit of volume. The property of a material that deter mines its resistance to the flow of an electrical current.
Volumetric Efficiency – The ratio of the actual capacity of the compressor to displacement, expressed in percent.
Waggler – See Oscillator.
Washer Drain Zone – The space in between spray zones within the washer tunnel.
Washer Process Zone – The spray treatment zone within the washer tunnel.
Washer Vestibule – The portion of the washer tunnel at the entrance and exit.
Water Spotting – Whitish blemishes on a pretreated part where minerals in the water have left a deposit on the surface.
Weathering Resistance – Also Weatherability. The ability of a surface to withstand the outdoor elements without degradation.
Weld Splatter – Beads of metal left adjoining a weld.
W.C. – A measurement of pressure in inches of water column. The pressure to be measured is introduced into one end of a u–shaped tube filled with colored water and the measurement is deter mined by how far up a tube the water is pushed.
White Blast – Blast cleaning to white metal surface.
Wrap – A characteristic of powder coatings in electrostatic application to seek out and adhere to areas of the substrate not in direct line of sight of the delivery system end point.