| Molds: Glossary of Terms |
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AcceleratorAn additive that reduces the gel and curing time of thermosetting plastics such as polyester gel coat and resin. Also called promoter or activator. -------------------------------------------------------------------------------------- AcetoneIn an FRP context, acetone is primarily useful as a cleaning solvent for removal of uncured resin from applicator equipment and clothing. VERY FLAMMABLE LIQUID. -------------------------------------------------------------------------------------- ActivatorSee Accelerator. -------------------------------------------------------------------------------------- AdditiveSubstance added to the resin mix to impart special performance qualities, such as ultraviolet absorbers, flame retarding materials (antimony trioxide, chlorinated waxes). -------------------------------------------------------------------------------------- Air DryTo cure at room temperature with the addition of catalyst but without the assistance of heat and pressure. -------------------------------------------------------------------------------------- AlligatoringWrinkling of the gel coat film resembling alligator hide. -------------------------------------------------------------------------------------- BackpourThe second pour or casting of cast polymer matrix into the female mold that creates the proper wall thickness of the product. -------------------------------------------------------------------------------------- Barcol HardnessA determination of hardness of a polyester using a Barcol Impressor. -------------------------------------------------------------------------------------- Cast PolymerA generic term referring to cast man-made material created by combining catalyzed polyester resin with inorganic fillers and color pigments. -------------------------------------------------------------------------------------- Catalyst InjectionUsed with spray equipment to catalyze the polyester at the spray gun, therefore eliminating the need to clean the system within the gel time of the polyester. Internal mix guns do require a solvent for cleaning the gun head. Injector: Atomizing air atomizes the catalyst at the injector unit itself. Pot: Catalyst is supplied to the spray gun, then air is introduced to atomize the catalyst. -------------------------------------------------------------------------------------- Catalyst (Peroxide)In FRP terms, a substance added to the resin or gel coat in controlled quantities to make it cure more rapidly. Usually it oxidizes an accelerator, creating free radicals, which in turn cures the resin or gel coat. -------------------------------------------------------------------------------------- CavityThe space between matched molds (pressure molds) in which the laminate is formed. Also a term for a female molds. -------------------------------------------------------------------------------------- CentipoiseMeasurement of viscosity as compared to water (1 centipoise). -------------------------------------------------------------------------------------- CobaltUsed as the accelerator for Methyl Ethyl Ketone Peroxide catalyzed polyesters. -------------------------------------------------------------------------------------- CrazingCracking of the resin due to internal stress. -------------------------------------------------------------------------------------- Cross-LinkingThe process of bridging two polymer chains, which converts a thermoplastic to a thermoset. -------------------------------------------------------------------------------------- CureThe polymerization of the transforming from the liquid to the solid state with maximum physical properties, including hardness. -------------------------------------------------------------------------------------- Cure TimeThe time required for the liquid resin to reach a polymerized state after the catalyst has been added. -------------------------------------------------------------------------------------- Cut-OutThe hole left in a flat deck or vanity top created by casting around a plug. The cut-out is used to accommodate either an undermount or drop-in bowl or bathtub. -------------------------------------------------------------------------------------- DelaminationThe separation of a laminate into layers owing to the failure of adhesion of the binder or failure of cohesion of the filler. -------------------------------------------------------------------------------------- DensityWeight per unit of volume, usually expressed as pounds per cubic foot. -------------------------------------------------------------------------------------- Dimensions(As measured from a position facing the front, leading edge of the product) -------------------------------------------------------------------------------------- Drop-In BowlAlso referred to as a self-rimming lavatory. The Drop-In Bowl fits through a cut-out in the vanity top. It has a lip or flange that rests on the vanity top holding it in place. -------------------------------------------------------------------------------------- Exothermic ReactionInternally developed heat accompanying a chemical reaction. -------------------------------------------------------------------------------------- Faucet Landing AreaThe area on the backside of the bowl that accommodates the faucet fixtures. -------------------------------------------------------------------------------------- FillersRelatively inert organic or inorganic materials which are added to plastics resins or gel coats for special flow characteristics, to extend volume, and lower the cost of the article being produced. -------------------------------------------------------------------------------------- Finished Edge/EndThe edge or end of a piece of cast polymer that is gelcoated and has been cast in contact with the mold surface to achieve a smooth, glossy finished surface. -------------------------------------------------------------------------------------- Flash PointThe lowest temperature at which a substance gives off enough vapors to form a flammable or ignitable mixture with air near the surface of the substance being tested. -------------------------------------------------------------------------------------- Flexural StrengthDetermination of the load required to cause failure by flexing. -------------------------------------------------------------------------------------- Fumed Silica (Aerosil, Cabosil)A very low weight thickening agent used in polyesters to increase thixotropic qualities. -------------------------------------------------------------------------------------- GelA partial cure stage of plastics resins in a viscous, jelly-like state where the liquid material starts to transform into a solid. -------------------------------------------------------------------------------------- Gel coatThe protective, transparent surface layer of polyester resin which is applied to the mold. The gel coat becomes the sanitary, glossy surface of the cast polymer product. -------------------------------------------------------------------------------------- Gel TimeThe length of time that a catalyzed polyester remains workable--- starts to solidify. -------------------------------------------------------------------------------------- GelationThe formation of a gel. -------------------------------------------------------------------------------------- Hot PotCatalyst is mixed with the gel coat or resin in the material container prior to spraying, as opposed to internal or external gun mixing. -------------------------------------------------------------------------------------- HumidityMoisture content of the air. -------------------------------------------------------------------------------------- InhibitorA substance designed to slow down or prevent a chemical reaction. -------------------------------------------------------------------------------------- Integral BowlA bowl that is cast as one piece with the vanity top. -------------------------------------------------------------------------------------- IsoAbbreviated terminology for isophthalic acid type resins and gel coats. -------------------------------------------------------------------------------------- Location of BowlAs determined from the location of the integral bowl(s) in the finished product as seen from a position facing the front of the vanity top.Right bowl: A bowl located on the right side of the vanity, the dimensions of which are given as the distance from the center of the drain to the right end of the vanity top. Left bowl: A bowl located on the left side of the vanity, the dimensions of which are given as the distance between the center of the drain to the left end of the vanity top. Double bowl: A vanity top with two bowls in which the dimensions are given as the distance between the center of the drain of each bowl. No bowl: A vanity top mold without a bowl. -------------------------------------------------------------------------------------- MassThe quantity of matter contained in a specified body. In reference to polyesters, mass is measured in mils or inches thickness of a film or casting. -------------------------------------------------------------------------------------- Master (Plug)The permanent tool used to build molds for the manufacture of cast polymer parts. -------------------------------------------------------------------------------------- Matrix (Batch, Mix)The combined mixture of resin, catalyst, and filler materials. -------------------------------------------------------------------------------------- MEK Peroxide (MEKP)Abbreviation for Methy Ethyl Ketone Peroxide, a strong oxidizing agent (free radical source) commonly used as the catalyst for polyester in the FRP industry. -------------------------------------------------------------------------------------- MEK SolventAbbreviation for Methyl Ethyl Ketone, a colorless fammable liquid commonly used in gun clean up procedures. -------------------------------------------------------------------------------------- MilThe unit used in measuring film thickness and the diameter of glass fiber strands, wire, etc. (one mil = .001”) -------------------------------------------------------------------------------------- MonomerA relatively simple compound capable of polymerization with itself or with a compatible resin. It is also used to dilute polyester. -------------------------------------------------------------------------------------- Net Wt of Mold
The approximate weight of the mold prior to packaging for shipment. The weights of the same mold may vary slightly due to the weight differences of the wood substructure. -------------------------------------------------------------------------------------- OrthoAbbreviation for orthophtalic acid type resins and gel coats. -------------------------------------------------------------------------------------- Parting AgentSee Mold Release. -------------------------------------------------------------------------------------- PatternThe initial model for making fiberglass molds. -------------------------------------------------------------------------------------- PeroxidesCategory of compounds containing an unstable O-O Group: Oxygen to Oxygen atoms. -------------------------------------------------------------------------------------- PigmentThe ingredient used in gel coats to impart color. -------------------------------------------------------------------------------------- PlugSee Master. Both terms used to imply the same meaning. -------------------------------------------------------------------------------------- Polyester (Unsaturated)A resin formed by the reaction between dibasic acids and dihydroxy alcohols, one of which must be unsaturated (typically maleic anhydride) to permit cross-linking. -------------------------------------------------------------------------------------- PolymerA large chemical chain composed of many identical groups, such as polystyrene. -------------------------------------------------------------------------------------- PolymerizationThe chemical reaction of cross-linking the molecules in the resin (see also Cure). -------------------------------------------------------------------------------------- Polyvinyl Alcohol (PVA)A liquid water soluble release agent for polyester. -------------------------------------------------------------------------------------- PorositySmall air bubbles in the gel coat film, too numerous to count. Generally smaller in size than pinholes. -------------------------------------------------------------------------------------- Post-CureExposure of the cured resin to higher temperatures than during curing, necessary in certain resins to attain complete cure and ultimate mechanical properties. -------------------------------------------------------------------------------------- Pot LifeSee Gel Time. -------------------------------------------------------------------------------------- PromoterSee Accelerator. -------------------------------------------------------------------------------------- Release AgentSee Mold Release. -------------------------------------------------------------------------------------- ResinAny of a class of solid or semisolid organic products of natural or synthetic origin, generally of high molecular weight having no definite melting point. Used in reinforced products to surround and hold fibers. Most resins are polymers. -------------------------------------------------------------------------------------- RTM (Resin Transfer Molding)Intermediate process of using matched molds (similar to match metal die) at low pressure and heat. -------------------------------------------------------------------------------------- Shelf LifeThe length of time an uncatalyzed polyester remains workable while stored in a tightly sealed container. -------------------------------------------------------------------------------------- Skin CoatThe first layer of laminate next to the gel coat. Generally only 1/16” thick to afford good roll-out and to reduce heat. -------------------------------------------------------------------------------------- Specific GravityThe ratio of the weight of any volume of a substance to the weight of an equal volume of some substance taken as a standard unit, usually water for solids and liquids, and air or hydrogen for gasses. -------------------------------------------------------------------------------------- Styrene MonomerAn unsaturated hydrocarbon, used in plastics. In polyester, it is a co-reactant diluent. -------------------------------------------------------------------------------------- Surfacing AgentA material that allows the surface of polyesters to cure. It limits adhesion of another coat of resin if the first is thoroughly cured. It may be removed by sanding or by rubbing with steel wool. -------------------------------------------------------------------------------------- ThermosetsMaterials that will undergo or have undergone a chemical reaction by the action of heat, catalyst, ultra-violet light, etc., leading to a relatively infusible state. Typical materials are aminos (melamine and urea), most polyesters, alkyds, epoxies, and phenolics. They are not reformable. -------------------------------------------------------------------------------------- ThixotropicA term describing materials more jelly-like at rest than when stirred or agitated. Agitation (shear) reduces the gel and increases the flow characteristics. -------------------------------------------------------------------------------------- Tooling Gel Coat/Laminating ResinSpecial polyesters designed to give ultimate strengths and cure values for mold making. -------------------------------------------------------------------------------------- UndercutNegative or reverse draft on the mold. Split molds are necessary to shape pieces that are undercut. -------------------------------------------------------------------------------------- Undermount BowlA separate bowl which is attached to the underside of the countertop. -------------------------------------------------------------------------------------- ViscosityThe internal resistance to flow of a fluid; thickness. -------------------------------------------------------------------------------------- Wet OutThe speed with which a reinforcing material can be completely saturated with resin. This rate is usually determined visually and measured in elapsed time. -------------------------------------------------------------------------------------- |