- Reconstituted WoodReconstituted Wood:Wood, in forms ranging from logs to coarse residues, which is first reduced to small fragments and then put back together again by special manufacturing processes into panel products of relatively large sizes and various thicknesses such as particleboard, medium density fiberboard and hardboard.
- Relative HumidityRelative Humidity:Ratio of the amount of water vapor present in the air to that which the air would hold at saturation at the same temperature.
- Resin SpotsResin Spots:Hard pieces of dark or black foreign material in face layer that are composed of glue and wood dust.
- RidgesRidges:Running parallel to the sanding direction, these thin, line-like streaks are slightly higher than the surrounding surface of the sanded board.
- Rough SandRough Sand:Area of a sanded panel that was not sanded with the finish sanding heads. The surface will appear and feel rough.
- RPMRPM:Revolutions per minute. The turning speed of a motor or cutting tool.
- Sander Belt Run OffSander Belt Run Off:A corner or edge of a panel that did not get sanded. This area is thicker than the rest of the panel and sometimes has a black marking on the unsanded area.
- Sander HesitationSander Hesitation:Sander head marks that appear across the panel width. The marks are low, concave indentations with a radius of the sander head, caused when the panel stopped under a sander head. At times, there will be primary sanding marks on the other side.
- Sander SkipSander Skip:Area of a sanded panel that was not sanded when surrounding areas were. These areas are usually low indentations in the panel.
- Sand-throughSand-through:A condition where the face layer has been sanded off, exposing the core. These areas may appear to be darker and larger particles will be exposed.
- Saturated PapersSaturated Papers:Decorative surface papers generally weighing between 60 and 130 grams per square meter. These papers are saturated with melamine or polyester resins and partially cured at the point of manufacture. Final curing is done at the time of hot press lamination. (See LPL)
- ScrewholdingScrewholding:A measure of the force required to withdraw a screw directly from the face or edge of a board stated in pounds (lbs).
- SizeSize:An additive introduced to the furnish for particleboard prior to forming, primarily to improve water resistance.
- SpringbackSpringback:Tendency of a pressed particleboard panel to return to its original uncompressed state.
- SquarenessSquareness:Right angles at the corners or equal diagonals from corner to corner.
- Starved GluelinesStarved Gluelines:A condition caused by an insufficient adhesive spread to adhere two materials together, as in a laminated panel construction.
- StepStep:Difference in height between panels when butted together due to thickness variations in panels normally of the same thickness.
- StreaksStreaks:Line-like streaks that appear the length of a panel parallel to the feed direction through the sander. These streaks are narrow, slightly higher than the sanded surface and are caused by metal in previous board stripping grit off the sanding belt.
- SubstrateSubstrate:A material that provides the surface on which an adhesive is spread for any purpose, such as laminating or coating.
- Surface DensitySurface Density:The weight of the extreme outer layer of face material, measured in pounds per cubic feet. Usually the layer with the highest density.
- SwellSwell:Thickness increase in a panel which can occur from excessive moisture pick up or wetting.
- Tensile StrengthTensile Strength:The greatest longitudinal stress a material can resist without tearing apart. Value in pounds per square inch (psi).
- ThermoplasticThermoplastic:Resins or adhesives that harden at room temperature and resoften upon exposure to heat.
- ThermosettingThermosetting:Resins or adhesives that cure at room temperature or in the hot press by chemical reaction to form rigid bonds that are not resoftened by exposure to heat.
- Thick and ThinThick and Thin:A thickness variation within a panel or between two panels.
- Unbalanced ConstructionUnbalanced Construction:When individual components or layers of a laminate do not respond equally to changes in moisture, thus causing warp.
- Uniform LoadUniform Load:A load distributed evenly across a shelf or panel.
- Urea Formaldehyde (UF)Urea Formaldehyde (UF):Interior thermosetting resin system (Type 1, ANSI A208.1) commonly used in the manufacture of particleboard.
- Vinyl FilmVinyl Film:Film made of polyvinyl chloride used for decorative surfacing and may be either clear or solid color. If it is clear, it is printed on the reverse side to protect the print. If it is a solid color, the printing is on the top.
- WarpWarp:When a board bends, twists or turns from a straight line due to unbalanced construction, excessive moisture pick up, wetting or other unfavorable exposures.
- Wet Bulb TemperatureWet Bulb Temperature:Temperature of the wet bulb thermometer in a relative humidity measurement. Compared with the dry bulb temperature to determine RH.