Specifying Aluminum Profile Finishes: More Than a Colour Number

A colour number is a starting point, not a complete finish specification for aluminum window and door profiles. Identify the finishing process, the intended appearance and the evidence required for the project. Keep those requirements connected to the actual profile references so the supplier knows which surfaces and components they apply to.

Start with the finishing process

Anodizing and powder coating should not be treated as two names for the same finish. The Aluminum Anodizers Council describes anodizing as an electrochemical process that develops an oxide finish from the aluminum surface. Architectural powder coating involves applying a powder coating and curing it, with substrate preparation and process control forming part of the quality system described by QUALICOAT UK & Ireland.

Record which process is proposed before discussing colour. Do not assume that a colour name used for one process defines an equivalent appearance in another. This guide does not rank one process as universally better or set a coating thickness or durability class for every project.

Describe appearance beyond the colour reference

Use the agreed colour reference, but also clarify the intended gloss and texture. If the description says bronze, silver or matt black, ask what physical reference will govern the discussion. The Aluminum Anodizers Council notes that alloy, temper, gloss, surface structure and colouring process can affect anodized appearance.

A rendered image or a phone photograph is useful for discussing a design direction, but should not be treated as an agreed physical colour reference. Define the comparison sample and review conditions with the supplier. Keep an identifiable record of the agreed reference, rather than relying on a screenshot whose display conditions are unknown.

Identify the components and visible surfaces

A window enquiry may include frames, sashes, trims and other visible parts. List which components should receive the specified finish and whether any intentionally differ. For aluminum profile extrusions, connect the finish description to the relevant drawing or item reference.

For example, an enquiry that requests a dark external frame and a lighter internal appearance should ask the supplier to confirm the proposed construction and available finishing arrangement. Do not assume that every aluminium profile system offers the same options.

Tell the supplier about the project conditions

Describe whether the components are intended for interior or exterior use and share relevant exposure information from the project team. Where a project specification names a standard, edition or performance requirement, provide that requirement instead of asking only for a generic premium finish.

Request a configuration-specific proposal from the aluminum profiles manufacturer or supplier. Do not infer suitability for a coastal or otherwise demanding environment from colour, appearance or a marketing adjective. Required performance and supporting evidence should be agreed for the actual project.

Separate appearance approval from performance evidence

An attractive sample is not proof of every coating property. QUALICOAT's explanation of architectural powder coating includes preparation, application controls and testing; appearance is only part of the discussion. Ask which reports, product references or approvals support the proposal and what their scope is.

If certification or a quality label is claimed, verify the relevant organisation, product or process scope. This article does not claim that CIMU or any proposed finish holds a particular label. Do not copy a generic logo into a project approval record as a substitute for verification.

Keep the finish schedule attached to the order

Use one controlled schedule to connect the finish decisions to the order. A practical record includes the following:

• Profile, system or component reference.
• Finishing process.
• Colour reference and physical comparison sample.
• Gloss and texture description.
• Applicable surfaces and any intended differences.
• Project exposure and specified performance requirements.
• Supporting evidence requested and received.
• Drawing or schedule revision and unresolved questions.

If a finish changes during procurement, update the relevant item references and obtain confirmation of the revised proposal. This applies to aluminum extrusions used for doors as well as windows. Do not let an earlier finish note remain attached to a later drawing without checking whether it still applies.

A concise enquiry you can adapt

Please confirm the proposed finishing process for the listed profile references, including colour, gloss, texture and the physical comparison sample. Identify the surfaces covered, the project requirements addressed and the supporting evidence available. Please state any options or limitations that differ from the attached finish schedule.

For a CIMU project discussion, send the finish schedule together with the relevant drawings and exposure requirements. Confirm availability and evidence for the proposed configuration; this guide does not promise a particular finish, certification, warranty or service life.

Sources

Aluminum Anodizers Council: What is Anodizing? https://members.anodizing.org/general/custom.asp?page=what-is-anodizing

Aluminum Anodizers Council: Anodic Coating Specifications. https://members.anodizing.org/page/anodic-coating-specifications

QUALICOAT UK & Ireland: What is Behind this Detailed Specification for Architectural Powder Coating? https://qualicoatuki.org/news/what-is-behind-this-detailed-specification

The checklist is a suggested procurement workflow, not a substitute for a project coating specification. Companion images are AI-generated illustrations, not actual CIMU product photographs or colour-accurate finish references.