< FINISHING SUMMARY
FINISHING KEYWORDS
ALLOY: A combination of two or more elements (copper/tin for example), to make a specific metallic material (bronze). Sometimes used as a generic word for the aluminium group of metals.
AMPS: (abbr.) Ampere (A) a SI unit of electrical current. TIG units suitable for welding cast copper alloy sections are usually capable of attaining at least 200 A, with 300 A+ preferred.
ANNEALING: Modification of a metallic structure through heat treatment, typically resulting in the softening of work hardened metals.
AUTOGRAPH BRONZE: A cast worked and finished by the artist themselves rather than foundry craftsmen.
BRAZING: Joining metals by flowing a flux protected filler into a heated joint by capillary action
BURNISHING TOOL: Metal ‘spoon like’ tool for polishing (esp. metal leaf).
CHASING: The fine finishing of cast surfaces.
CHASER FITTER: A specialist in the construction of large scale casts.
COLISONNÉ: Technique of applying enamel or coloured resin etc to areas of a work bordered by metal strips.
CONTRACTION: The tendency for metals (as well as other materials), to shrink upon cooling or curing etc. Where dimensions are critical, this effect may be allowed for by slightly increasing the size of a master pattern. The correct allowance can be calculated with the aid of a patternmaker’s contraction rule.
CREEP: The tendency for metals under lateral load to sag over time, sometimes causing unsupported structures to deform under their own weight (esp. lead and other soft metals).
DCEN: (abbr.) Direct Current Electrode Negative. The terminal connections for standard TIG and MMA welding using a DC current. Electrode attached to negative (-) terminal, return lead to (+) positive terminal.
DCEP: (abbr.) Direct Current Electrode Positive. The rarely used reversal of terminal connections as described for DCEN welding.
DRY JOINT: General term any joint which is either self fixing (ie panned over) or held in place by bolts, rivets, staples etc.
FETTLING: The removal of casting attachments, core and surface debris from casts.
FILLET: A strengthening design feature used in patternmaking and fabrication, esp. where planar surfaces intersect. Also types of ‘branch’ welded joint – the lap fillet and tee fillet.
FIRE GILDING:Traditional technique of applying gilding metals carried within a mercury amalgam, now disused due to highly toxic vapour discharge.
FLOW WELDING: Traditional technique of uniting cast sections by flooding a molten metal through a joint to fuse the parent metals together.
FUSION JOINT: Fully welded joint forming a homogeneous metal structure.
GUSSET: A strengthening design feature used in patternmaking and fabrication etc, to stiffen adjoining angular sections (see also WEB).
HAZ: (abbr.) Heat Affected Zone. The area of weld deposit and parent metal affected by heat input. Typical consequences can include annealing and distortion.
JIG: A temporary device for holding an workpiece in location, usually during welding, drilling or fixing.
KERF: Material lost in the width of a cut during oxy-gas, plasma and similar cutting processes.
LEAF (FOIL): Gold, silver, copper and other fine metal used for gilding and other effects.
MACHINE TOLERANCE: Excess metal deliberately added to cast surfaces for removal during finishing. Allows an accurate dimension to be machined after contraction.
MAGS: (abbr.) Metal Arc Gas Shielded. Electric welding process; a term which encompasses the MIG process.
MANDREL: Tapered, reverse screw thread mounted on a motor, to which various abrasive attachments are added for cleaning and polishing operations.
MATTING TOOLS: Hammer driven tooling similar in appearance to chisels, but with textured faces. Used during fine finishing for imparting a variety of surface effects to castings during chasing.
MIG: (abbr.) Metal Inert Gas. Electric welding process. Uses an inert gas shield and continuous feed spool mounted filler wire.
MMA: (abbr.) Manual Metal Arc. Electric welding process using flux-coated metal electrodes. Also known as STICK welding.
MORDANT: A solution with the ability to etch or corrode a metal. Specifically, dilute nitric acid (for copper alloys) & spirit of salts [dilute hydrochloric acid] (for carbon steels).
MSDS: (abbr) Material’s Safety Data Sheet, an item of literature supplied with products such as chemicals etc giving comprehensive health and safety information. Also related to risk assessment and other occupational health and safety data.
OXY-GAS: Gas fuelled welding and cutting process. Also known as O/A, Oxy-Acetylene and Oxy-Propane.
PATINATION: The natural or artificial colouring of metals through chemical exposure and oxidisation.
PATINA NOBILE: (It.) Patina Nobile. A naturally deposited patina esp.VERDI GRIS on copper and selected copper alloys.
ROUGE: Abrasive medium used in metal polishing process, also COMPOUND.
SIGHTING: Short stub of cast metal, left proud of the cast surface after a runner, riser or other spent casting attachment is cut off.
SOFT SOLDERING: Low temperature joining process using lead/tin solder wire and a flux.
SPATTER: Extraneous and unsightly globules of molten metal. Typically dispersed over the cast during welding operations (esp. MIG), adhering to affected surfaces and requiring later removal.
STICK WELDING: See MMA
TAGS: (abbr.) Tungsten Arc Gas Shieded. Electric welding process using a gas shielding and non-consumable tungsten electrode. A generic term, TAGS encompasses TIG, Argonarc, Helishield and Heliarc processes.
TEMPERING: Part of a heat treatment process to harden softened metal structures (esp. tooling).
TEMPLATE: A reference which sets out or provides a reference for the accurate location of items such as clearance holes, fixings, cut profiles etc.
TIG: (abbr.) Tungsten Inert Gas, also ‘Argonarc’, see TAGS.
VERDI GRIS: (Fr.) Literally: ‘green-grey’, the classic natural patination acquired by oxidised copper and many of it’s alloys. Usually develops over earlier deposited red and black oxide layers.
VOLT: (v) SI unit of electromotive force (EMF) UK/Australia domestic voltage 240v. UK industrial voltages: 415v (plant) & 110v (portable hand tools). The open circuit voltage (OCV) for arc initiation on industrial TIG & MMA welding sets is (fixed) at a value normally less than 70-80v. Voltage settings on MIG welding sets are adjustable to vary welding characteristics.
WELDING: Fusion joining of metals to form a homogeneous joint.
WORK HARDENING: Hardening of a metal’s crystalline structure. Often arising as a result of cold working/forming processes. Can result in surface defects, embrittlement and cracking. Normally reversible by annealing.
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