Aluminium doors and windows are assembled by fabricators from extruded profiles, usually 6063 or 6060 in the T5 or T6 temper, with wall thicknesses of roughly 1.2 to 3 mm and an anodised, powder-coated or PVDF finish. This guide covers the main profile families, alloy and temper choices, finish classes, tolerances and packing, so that fabricators and project buyers can specify the aluminium correctly. Metline supplies the profiles and accessories; the windows and doors themselves are made by the fabricator or system company.
A window or door frame is a set of extruded aluminium sections cut, machined and joined at the corners, with glass, gaskets, hardware and, in insulated systems, polyamide thermal barriers. The profile shape does most of the engineering work: it carries wind load, holds the glazing, drains water and locates the seals.
Aluminium displaced steel and wood in most commercial glazing because extrusion can put complex functional geometry into a single section: screw ports, gasket grooves, glazing beads, drainage chambers and hardware channels are all formed in one pass through the die. The metal does not rot, rust or swell, takes durable decorative finishes, and is fully recyclable at the end of the building's life.
Compared with uPVC, aluminium frames are far stiffer, so sightlines can be slimmer and openings larger; the trade-off is thermal conductivity, which is why insulated (thermal-break) profiles now dominate in cold and temperate climates. For a broader introduction see our separate window profile guide and door profile guide; this page focuses on the full range of profile families and how to specify them.
Inner and outer aluminium sections joined by glass-fibre-reinforced polyamide strips (typically PA66 GF25) that are inserted and rolled in. Frame U-values fall sharply; used for casement, tilt-and-turn, lift-and-slide and entrance doors in insulated buildings.
Single-piece sections for warm climates, interior partitions, shopfronts and secondary glazing, where thermal performance is not required and cost and slim lines matter.
Frames with tracks and interlocks, sashes and rollers channels. Heavy lift-and-slide doors use deeper, thicker sections to carry large glass panels.
Outer frame, sash and mullion sections with gasket grooves and Euro-groove hardware channels for hinges and multipoint locks.
Mullions, transoms and pressure plates for stick or unitised facades; see the curtain wall profile page.
Blade and frame sections for ventilation louvres, sun shading and screens, often aerofoil or Z-shaped and hollow for stiffness.
Roll-formed or extruded slats, guide rails and end bars. Extruded slats are stronger and used for security shutters.
Glazing beads, corner cleats, flyscreen frames, sills, couplers and trims supplied with the main system.
Standard profiles finished with sublimated woodgrain or combined with timber in aluminium-clad wood systems.
6063 and its European sibling 6060 extrude at high speed through complex hollow dies and give the smooth surface needed for decorative finishes. 6005 and 6082 are used for heavier structural members where higher strength is required.
| Alloy and temper | Min. tensile strength | Min. yield strength | Typical use |
|---|---|---|---|
| 6063-T5 | 150 MPa | 110 MPa | Standard frames, sashes, beads and trims |
| 6063-T6 | 205 MPa | 170 MPa | Larger doors, mullions and wind-loaded members |
| 6060-T5 / T6 | Slightly below 6063 at the same temper | European system profiles; excellent anodising finish | |
| 6005-T5 / 6005A-T6 | Higher than 6063-T6 | Heavy mullions, sliding door frames, structural sections | |
| 6082-T6 | Highest of the group | Structural supports and brackets rather than visible frames |
6063 minimums from ASTM B221 (thickness up to 12.5 mm). European profiles are specified under EN 755-2, whose minimums vary by thickness band; the certificate shows the values met by the lot.
Hardness is the quickest check on site or at goods-in. Webster hardness readings of about 8 – 12 HW are typical for correctly aged 6063-T5; markedly lower readings point to under-ageing and soft profiles that may deflect or let screws strip.
Wall thickness is set by structural need, by the screw ports and by local rules. Thin walls save metal and cost but reduce stiffness and screw holding, and they show distortion after finishing.
| Profile type | Common wall thickness | What drives it |
|---|---|---|
| Interior partitions and light frames | 0.8 – 1.2 mm | Appearance and handling only |
| External window frames and sashes | 1.2 – 2.0 mm | Wind load, screw retention, hardware fixing |
| External doors and sliding door frames | 1.8 – 3.0 mm | Door weight, hinge loads, abuse resistance |
| Curtain wall mullions | 2.0 – 3.5 mm and more | Span and wind pressure |
| Louvre blades | 1.0 – 2.0 mm | Span between supports and wind |
| Finish | Typical thickness | Quality standard | Notes |
|---|---|---|---|
| Anodising | 15 – 25 µm for exterior use (classes 15, 20, 25) | EN ISO 7599, Qualanod | Natural silver, bronze, champagne and black; metallic look; class 20 or 25 for coastal and industrial sites |
| Polyester powder coating | 60 – 120 µm, 60 µm minimum on significant surfaces | Qualicoat class 1/2/3, AAMA 2603/2604/2605 | Any RAL colour; super-durable (class 2) and class 3 powders for long colour life |
| PVDF (fluorocarbon) coating | About 30 – 60 µm in two or three coats | AAMA 2605, Qualicoat class 3 | Best colour and gloss retention for high-rise and coastal projects |
| Electrophoretic coating | 10 – 25 µm over anodising | Supplier specification | Clear or tinted lacquer over anodising for extra protection and gloss |
| Woodgrain sublimation | Over a powder base coat | Qualideco, supplier specification | Printed wood effect for traditional or residential designs |
| Mill finish | None | — | For profiles finished after fabrication or hidden internal sections |
Specify the finish class, not just a colour. A powder coating to Qualicoat class 1 on a seafront building will chalk and fade years before a class 2 or PVDF system, and anodising thinner than 15 µm is not suitable for exterior use. Agree colour and gloss on approved samples, and request the finish certificate with each delivery.
Finished profiles are easily scratched, so packing matters as much as the extrusion. Typical arrangements are:
Ask for the protective film to be suitable for the outdoor exposure time on site, since some films leave residue if left in sunlight for months.
6063 is the standard alloy worldwide, with 6060 widely used in Europe. Both extrude complex hollow shapes with a smooth surface for anodising or coating. 6005 or 6082 is chosen for heavy structural members.
T5 profiles are cooled at the press and artificially aged; T6 profiles are fully solution treated before ageing and are stronger. 6063-T5 has a minimum yield of 110 MPa and 6063-T6 about 170 MPa under ASTM B221.
External window frames and sashes typically have walls of about 1.2 – 2.0 mm, and external doors 1.8 – 3.0 mm. The right thickness depends on wind load, opening size, hardware and any minimum set by local building rules.
An aluminium profile split into inner and outer parts joined by glass-fibre-reinforced polyamide strips. The polyamide interrupts heat flow through the frame, cutting its U-value and preventing condensation on the inside face.
Anodising gives a hard, metallic finish that does not peel, best in natural and bronze tones. Powder coating offers any colour and good durability; for coastal or high-rise projects choose Qualicoat class 2 powders or PVDF.
No. Metline supplies the aluminium: extruded profiles to your drawings or system, thermal-break profiles, sheet and accessories, finished and cut to length if needed. The windows and doors are fabricated by your own workshop or system partner.
Send your section drawings or system details, finish and quantities. We will reply with alloy, temper, finish options and delivery.
