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A is for Aluminium! The Complete Guide to Aluminium – from GA

Here at Gooding Aluminium we know our acute angles from our perforated sheet, we thought it would be really helpful to our customers, to give a concise definition of all things aluminium.  So please read our GA Glossary of Terms and let us know what you think!  Have we missed anything?  If so, do tell us by leaving your comments below!

Anolight Cladding Panels


Read: The Gooding Guide to Aluminium


Acute angle: A two-sided section with equal or unequal legs joining at less than 90° to each other.

Ageing: The hardening process which either takes place naturally at room temperature over a period of time, or by heating for a much shorter period at a relatively low temperature (known as artificial ageing).

Annealing: A thermal treatment for softening aluminium.

Anodising: The electrolytic process which thickens the natural oxide film on the surface of aluminium. The finish results in enhanced durability, weather resistance and appearance.

Anodised natural finish: A matt silver finish (without the addition of coloured pigments).

Anodised silver finish: A different description of the above finish.

Architectural quality: A grade suitable for the anodising process.



Base thickness: The thickness of a tread grip plate not including the lozenge height.

Blank: A sheared to size piece of metal.

Billet: The short slug of aluminium used in the extrusion process.

Box section: A square section with a square hollow centre.

Buffing: A mechanical finishing operation carried out with fine abrasives to produce a lustrous effect.

Busbar: A metal / grade with excellent electrical conductivity properties.

Burr: The thin ridge or area of roughness left by a metal shearing operation.

Butt strap: Used to join two end pieces of metal together.


C or U section: A three sided channel with legs or upstands at 90° to baseline.

Carrier bar: Usually a section of aluminium angle or aluminium flat bar rear fitted to and joining together a number of horizontal profiles eg louvre blades.

Chair section: A small ‘h’ shaped profile.

Chamfer: An angled edge.

Chemical brightening: A treatment to improve surface reflectance.

Chequer pattern: Describes a sheet / plate with an upraised lozenge pattern on one side, resulting in a non-slip surface.

Chromating: Chemical conversion process which acts as a surface pre-treatment for improved corrosion resistance and paint adherence.

Clean: The mechanical removal of an upraised weld-bead.

Coil anodising: Coiled material is unrolled and passed through the anodising plant in one operation, achieving close control of surface shade and finish.

Cold working: Altering the metal shape or dimensions at atmospheric temperature.

Corner protectors: Normally a 90° right-angle section fixed to exposed wall corners for added protection

Corrosion: The combination of metal with corrosive agents and the subsequent wasting away of the metal.

Corrugated: Profiled sheet formed to numerous ribbed and curved designs.

Crazing: The surface condition arising from forming pre-anodised material.

Crimp: To fold and pinch two pieces of metal together in making corners.


Deburr: The removal of sharp or irregular edges.

Dead lengths: Exact lengths within established tolerances.

Die: A round steel plate containing a cut out of the required profile shape, which the aluminium is forced through.

Die line: A longitudinal depression or protrusion formed on the surface of extruded sections. Die lines are visible to a degree on all aluminium extrusions and are caused by a wearing of the die bearing.

Dimensions: The measurements of any aluminium item are always taken to be the overall or outside dimensions unless otherwise stated.

Dowel: Solid round bar or pin cut to the required length.

Ductility: The property of metal which allows it to be deformed cold without fracture.

Duralumin or Dural: Generic terms used to describe medium strength aluminium alloy.

Durbar: A trade name for aluminium treadplate.


Edge: The side of an item

Edge – sheared:  The edge produced by the cold shearing of metal between two moving blades or between one moving blade and fixed edge.

Edgewise bow: The bow in sheet or strip which often occurs, to a lesser or greater degree, after shearing, usually measured in terms of offset from a straight edge.

Electrolytic polishing: Polishing effected by immersing the object to be polished in a suitable tank while an electric current is passed between the object and a cathode. The object to be processed is the anode and is polished by loss of its surface atoms.

End: The edge of the longest dimension.

Etching: The production of a matt finish by chemical (acid or alkali) treatment.

Expanded: Incised sheet material which is stretched into diamond or elongated shapes.

Ex-stock: From aluminium stock with immediate availability.

Extrusion – direct process: At high pressure an aluminium billet is pushed through a die with an aperture of the required shape (the majority of sections are extruded this way).

Extrusion – indirect process: At high pressure an aluminium billet is pulled through a die with an aperture,  of the required shape (miniature and intricate items are produced by this method).


Fabrication: The process of manufacturing to detailed requirement.

Face: The front surface of an item.

Finger plate: Usually a rectangular piece of flat sheet, screwed or bonded around the handle area of a door.

Fishplate: A flat piece of metal butt-joining one Iength to another.

Fishtail: A flat piece of metal splayed and slit at one end to facilitate keying into brickwork / concrete, etc.

Flange: Projecting upstand/s or leg/s on a section of profile.

Flashings: Normally factory-formed pressings to desired size and shape requirements for use as weatherproofing material on parapets, etc.

Form: An item produced by bending sheet material to the required shape, resulting in radiuses or curved corners.


Gap: The inside dimension between two parallel flanges.

Girth: The overall width of an item.

Grain flow: Elongation of the grain structure in the direction of working.


H section: Identical in shape to a capital ‘H’ but with varying distances between the outside flanges to accommodate different board or glass thicknesses.

Heat treatment: An operation or combination of operations involving the heating and cooling of the metal for the purpose of obtaining certain desirable mechanical properties


Ingot: The original form into which aluminium is cast for subsequent rolling or extruding.


Jay: Similar to an odd leg channel but with the baseline curving from the back leg to the front leg.


Kicking plate: Usually a rectangular piece of flat metal screwed or bonded to the full width of a door at floor level.


L shape: A two sided section with equal or unequal flanges joining at 90° to each other.

Leg: Protruding flange or rib of section.

Louvre vents:  a) One-piece formed louvre, each louvre pushed out by a press tool.
b) Profile blades attached to surround frame or rear carrier bars.


Mill: Sheet or extrusion plant.

Mill finish: Raw aluminium, as it comes from the mill. Surface can vary from a dull to semi-bright appearance.

Moulding: Trim profiles produced in a malleable condition, suitable for cold forming.


Notch: A ‘cut out’ or ‘cut back’ from one end or edge


Obtuse angle: A two-sided section with equal or unequal legs joining at more than 90° to each other.

Oddleg channel: Three sided aluminium section with one leg longer than the other but both joining the baseline at 90°.

Ovality: The departure of the cross section of a round tube or bar from a true circle.

Over pattern / over pattern thickness: Describes the overall thickness of an aluminium treadplate, including the lozenge height.


Part tool/die cost: Custom-made extrusions require a contribution towards tool / die production costs.

Patterned: A sheet product with a pattern, usually on one side, for decorative purposes.

Perforated: Perforated sheet material with punched holes.

Plate: Rolled product with a thickness of more than 4.7mm.

Pitting corrosion: Pitting corrosion is a localized condition on the metal surface, caused by reaction with atmospheric contaminants.

Polishing: The application by mechanical means of a grained or smooth surface.

Pop-rivetting: A mechanical means of joining from one side only, two pieces of metal.

Profile: The end / sectional view of an item.

Polythene / plastic film: A thin, peelable protective film, applied to sheet material before processing commences.


Quenching: Rapid cooling of metal by immersion in oil, water or another medium.


Radius: A corner or edge with a rounded face.

Random lengths: Varying overall profile length.

Rip-saw: The cutting process which reduces or removes flange dimensions.

Rivet: A short metal pin for fastening two pieces of metal together, having a head at one end with the other end being hammered flat after location.

Rolling: Sheets or sections passed through a series of rollers to produce the desired shape.


SAA (satin anodised aluminium): Natural anodised aluminium.

Sealing: A treatment applied subsequent to anodising reducing the surface porosity.

Shate: Rolled products with a thickness of more than 3.2mm but no greater than 4.7mm.

Sheet: A rolled product with a thickness up to and including 3.2mm.

Sizes: All standard product dimensions are subject to the appropriate international tolerance standards.

Slab: A semi-finished aluminium product, approximately rectangular in shape, from which flat rolled items such as sheets, plates, etc, are produced.

Slitting: Cutting a strip into a number of narrower strips by means of rotary cutters.

Slug: The piece of material removed by the punching / perforating process.

Strain hardening / work hardening: Modification of metal structure by working at room temperature, resulting in an increase in strength / hardness, with a reduction in ductility.

Solution heat-treatment: Heating at a prescribed temperature for a given period of time, followed by a rapid cooling or quenching.

Split-batten: A narrow offset or jay type profile used for ‘invisibly’ hanging wall panels and boards.

Straightening: Correction of shape distortion by mechanical means.

Strip: a) Sheet material sheared to narrow width.
b) An extruded aluminium flat bar.

Surface bloom: Aluminium surface discolouration, that can occur after prolonged exposure to moist air conditions or during heat treatment processes.


Table: The top plain surface.

Temper designation: The amount of work hardening or rolling an item has received.

Tolerance: The allowable deviation from a given dimension.

Top hat: A three sided channel section with extra flanges joining and facing outwards at 90° to each leg or upstand.

Tube: A circular section with a hollow centre.


Water bar: Flat strip or bar.

Wallboard section: Profiles designed to accept wall panels of varying thicknesses.

Water stains: Surface oxidization, usually caused when moisture is present between closely stacked metal surfaces.

Web: The central part of a section that joins two flanges together.

Weld bead: The narrow moulding resulting from the welding process.

Wrought product: Items produced from the extrusion and sheet production processes.


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