Joint and trim profiles

Y Section Aluminium Extrusion

A Y section is an aluminium extrusion with a single stem and two arms spreading from it, like the letter Y. The stem locates in a joint, groove or slot while the arms cover or grip the edges on either side, which makes it a neat way to join panels, frame glass, house LED strip or cover expansion gaps. Metline supplies standard and custom Y profiles in 6063, 6060, 6061 and 6005A, finished and cut to length, worldwide.

By Metline Technical Team · Updated 17 October 2026

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Extruded aluminium Y section joint profiles

Shape: Stem + two arms
Alloys: 6063 · 6061 · 6005A
Gap sizes: About 5 – 30 mm
Finishes: Anodised, powder, brushed

Overview

What is a Y section extrusion?

The value of a Y section is that it does two jobs at once: the stem positions the profile and holds it in place, and the arms present a finished face that hides a gap or retains a component on either side.

The most common form is a joint cover strip. The stem is pushed or bonded into the gap between two wall, ceiling or floor panels, and the angled arms lie over the panel edges, hiding cut edges and absorbing small differences in panel position. Such strips are sold by the gap they fill, for example 7, 9.5, 20 or 26 mm.

Other Y sections include glazing profiles whose arms grip a glass edge or gasket, LED Y channels that hold an LED strip at an angle in a corner and spread its heat, bathroom panel joints that seal wet-wall panels meeting at a corner, and structural Y shapes used in solar frames, assembly lines and heat-sink assemblies.

Most Y sections are small, thin-walled and seen, so they are extruded in 6063 or 6060 for a clean surface and even anodising. Load-bearing Y shapes are made in 6061 or 6005A.

Product types

Common Y section types

Decorative joint strip

Covers the gap between panels in walls, ceilings and shop fittings. Chosen by gap width and arm length.

Y trim for panels

A slim profile to finish panel edges and joints, often in matching anodised or powder colour.

Glass framing Y profile

Grips a glass edge with a gasket for partitions, balustrade infills and cabinets.

LED Y channel

Holds LED strip at an angle in corners and coves; the aluminium body acts as a heat sink. Used with a diffuser cover.

Wet-wall panel joint

Seals bathroom or shower panels where they meet, keeping water out of the joint.

Custom Y profile

Your own dimensions and features, such as screw ports or barbs, extruded from a new die.

Gap filled (stem width)	Typical application
About 5 – 7 mm	Thin wall panels, shop fittings, furniture
About 9 – 10 mm	Standard board and panel joints, partitions
About 18 – 20 mm	Thicker boards, expansion joints in linings
About 25 – 30 mm	Wide joints, cladding and ceiling systems

Material

Alloys, tempers and properties

Alloy and temper	Standard and size band	Tensile strength, min.	Yield strength (0.2 %), min.	Elongation, min.
6060-T5	EN 755-2, wall ≤ 5 mm	160 MPa	120 MPa	8 %
6063-T5	ASTM B221, ≤ 12.5 mm	150 MPa (22 ksi)	110 MPa (16 ksi)	7 – 8 %
6063-T6	ASTM B221 / EN 755-2	205 – 215 MPa (30 ksi)	170 MPa (25 ksi)	8 %
6061-T6 / T6511	ASTM B221 / B308	260 MPa (38 ksi)	240 MPa (35 ksi)	8 %
6005A-T6	EN 755-2, open profile ≤ 5 mm	270 MPa	225 MPa	8 %

Specified minimums for extruded profiles; thicker walls fall into different bands. Typical values run 10 – 20 % higher (6061-T6 typically 310 MPa tensile, 276 MPa yield). Design to the minimums and the actual figures on the mill certificate.

Alloy	Si	Fe	Cu	Mn	Mg	Cr	Zn	Ti
6060	0.30 – 0.6	0.10 – 0.30	0.10	0.10	0.35 – 0.6	0.05	0.15	0.10
6063	0.20 – 0.6	0.35	0.10	0.10	0.45 – 0.9	0.10	0.10	0.10
6061	0.40 – 0.8	0.7	0.15 – 0.40	0.15	0.8 – 1.2	0.04 – 0.35	0.25	0.15
6005A	0.50 – 0.9	0.35	0.30	0.50	0.40 – 0.7	0.30	0.20	0.10

Single values are maximums. Others 0.05 % each, 0.15 % total; aluminium is the remainder. Limits follow the Aluminum Association registrations and EN 573-3.

For trims and joint strips, 6063-T5 is ample: the profile is not structural and its surface matters more than strength. For LED channels, the high thermal conductivity of 6063 (about 200 W/m·K) helps keep LEDs cool and extends their life. Where a Y shape carries load, as in a solar frame or machine part, choose 6061-T6 or 6005A-T6.

Surface finishes

Finishes and colours

Mill finish: economical; for hidden or painted-over joints
Clear or satin anodised: hard-wearing metallic finish for visible trims and LED channels
Colour anodised: light bronze, black, gold and champagne to match window and furniture hardware
Powder coated: any RAL colour, ideal for matching painted panels
Brushed: satin texture for a premium interior look
Wood grain: timber-look finish for interior panelling

Anodic film thickness and powder coating class should suit exposure: indoor trims commonly use 10 – 15 µm anodising, while exterior parts call for 20 µm or more or an architectural powder system.

Processing & installation

Processing and installing Y profiles

Measure the gapMeasure the actual joint width along its length; choose a stem that fits snugly or has barbs that grip.
CutCut profiles to length with a fine carbide blade; mitre at corners for a continuous trim line.
FixPress-fit barbed stems, bond plain stems with a suitable adhesive or sealant, or screw through the stem where designed.
SealIn wet areas, run a bead of silicone along the arms or use a profile with integral sealing lips.
FinishRemove protective film after the surrounding work is complete.

Cutting to length, drilling, punching, mitring and bending can be done before delivery so profiles arrive ready to install.

Applications

Where Y section aluminium is used

Interiors: wall-panel, ceiling and furniture joints; edge trims
Bathrooms: waterproof joints between wall panels
Windows, doors and curtain walls: glazing and joint profiles
Lighting: corner and cove LED channels
Solar: frame and mounting profiles
Industry: assembly-line guides and heat-sink assemblies

Standards & quality

Standards, tolerances and packing

Y sections are supplied to ASTM B221 or EN 755-2, with tolerances to EN 12020-2 for precision 6060/6063 profiles, EN 755-9 or ANSI H35.2. The stem width is the critical fit dimension and is gauged during production. Each delivery comes with an EN 10204 3.1 mill test certificate; RoHS or REACH declarations are available on request.

Finished profiles are film-protected, wrapped in foam or paper, bundled or boxed and palletised or crated for export.

Sources

References and standards

ASTM B221 – Extruded bars, rods, wire, profiles and tubes (aluminium and its alloys)
EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
EN 12020-2 – Extruded precision profiles in alloys EN AW-6060 and EN AW-6063: tolerances
ISO 7599 – Anodizing of aluminium and its alloys

FAQ

Y section aluminium (aluminum) profiles: FAQs

What is a Y section aluminium profile used for?

Mainly to cover and seal joints between panels, to frame glass, to hold LED strip in corners and as trims in furniture and interiors. Structural Y shapes are also used in solar frames and machinery.

How do I choose the right Y strip size?

Measure the gap the stem must fill and choose a profile made for that width, for example 7, 9.5, 20 or 26 mm. Check that the arms are long enough to cover the panel edges.

Which alloy is best for Y profiles?

6063-T5 for trims, joint strips and LED channels because of its surface and anodising quality; 6061-T6 or 6005A-T6 where the profile carries load.

Are Y profiles suitable for bathrooms?

Yes. Anodised or powder-coated aluminium resists moisture well. Use a profile with sealing lips or add silicone along the arms to keep water out of the joint.

Can you make a custom Y section?

Yes. Send a drawing with dimensions and tolerances; a new die is made and samples can be approved before production.