The natural aluminum surface straight from the press — clean, uncoated, and ready for structural or concealed applications.
Mill finish is the natural aluminum surface produced directly by the extrusion or casting process — no coating, no treatment, no additional processing beyond what the die and press produce. The surface has a smooth, slightly matte-metallic appearance with the characteristic longitudinal marks left by the extrusion die.
Because no coating is applied, mill finish is the lowest-cost finish option and the fastest to supply. It is the ideal specification for profiles and components that will be installed in concealed or structural positions, that will receive a subsequent coating at the fabrication stage, or that are used in interior applications where moderate corrosion resistance is sufficient.
Mill finish is also the starting point for all of CANEX's subsequent surface treatment processes — anodizing, powder coating, wood effect, grinding, barrel finishing, and shot blasting all begin from mill finish stock. Understanding the mill finish baseline is essential for specifying the right subsequent treatment for your application.
Mill Finish — Natural Aluminum
Mill finish parameters vary slightly with alloy composition and die condition, but the following specifications represent CANEX standard output from our extrusion and casting lines.
| Surface Condition | Uncoated, natural aluminum |
| Roughness (Ra) | Approximately 0.4–1.6 μm (varies by alloy and die condition) |
| Appearance | Smooth metallic, slightly matte with die marks |
| Corrosion Resistance | Moderate — suitable for interior or protected applications |
| Cost | Lowest cost finish option — no additional process cost |
| Compatible Alloys | All CANEX extrusion and casting alloys |
| Best For | Structural, concealed, subsequently coated applications |
| Not Recommended For | Exposed coastal environments, food contact, high-corrosion areas |
Mill finish is not a compromise — it is the optimal specification for a range of applications where coating adds cost without adding value. Here are the three primary use cases.
Cost-Sensitive Projects
When project budget is the primary constraint and the profile is structural or concealed, mill finish delivers the required performance at the lowest possible unit cost. No coating line, no cure oven, no consumables — the savings are direct and significant.
Will Be Powder Coated or Painted
Many fabricators apply their own coating at the project stage. In this case, mill finish is the correct base specification — it allows the fabricator to apply their chosen color, brand, or system without paying for a CANEX coating that will be painted over.
Hidden Structural Applications
Profiles used inside walls, behind cladding, in concrete, or in concealed structural positions never see the light of day. For these applications, mill finish provides adequate corrosion protection at zero additional cost.
Mill finish is the starting point for every subsequent surface treatment available at CANEX. All five finishing processes below accept mill finish stock as their input material.
Powder Coating
Mill finish profiles go through our 9-stage chrome-free pretreatment line before powder application. QUALICOAT Seaside certified.
Wood Effect
Mill finish is powder coated first (base coat), then receives film sublimation transfer of wood grain or stone pattern.
Grinding & Polishing
Mill finish is ground to remove die marks and achieve mirror-bright or brushed finishes as low as Ra 0.1–0.2 μm.
Barrel Finishing
Small mill finish components are tumbled with abrasive media for uniform deburring and satin surface — Ra ~1.6 μm.
Shot Blasting
Mill finish profiles are shot blasted for improved coating adhesion or industrial-matte appearance — Ra ~3.2 μm.
All Alloys Compatible
Mill finish is available on all CANEX extrusion alloys (6060–6101, 1050) and all casting alloys (A356, A380).
Mill finish aluminum is specified across a wide range of structural, industrial, and supply-chain applications where the raw aluminum surface is sufficient or where subsequent coating is planned.
Structural Framing
Hidden Construction Elements
Industrial Profiles
Pre-Anodize Stock
OEM Base Material
Fabricator-Coated Profiles
Interior Furniture Frames
Transit & Transport Structures
Get a quote for your specific requirements. Our engineering team responds within 48 hours.