Aluminum is a popular metal used in a variety of applications from construction to consumer goods due to its lightweight, corrosion resistant, and durable properties. Aluminum can be produced in different colors through anodizing, powder coating, or painting processes to suit various aesthetic, functional, or identification needs. Understanding aluminum color codes can help specify the right finish for a particular aluminum product or application.
The most common aluminum color finishes include clear, black, and silver. Silver aluminum refers to aluminum with a shiny, metallic silver-gray appearance in its natural uncoated state. However, there are specific color codes used to designate different shades and types of silver aluminum finishes.
Color Code Systems for Aluminum
Several color code systems exist for classifying aluminum finishes. Some of the most common are:
- RAL Color Codes – RAL is a color matching system used globally for standardizing colors across different materials and surfaces. RAL 9006 is the code for White Aluminum, RAL 9007 for Gray Aluminum, and RAL 9006 for Silver Metallic Aluminum.
- Pantone Matching System (PMS) – PMS is a proprietary color space with over 1,100 solid colors used in printing and design. PMS 877 is closest to silver aluminum.
- Federal Standard 595C – This system is used to standardize paint colors for military and government applications. FS 17178 is the code for aluminum paint finishes.
- ASTM B209 – The Aluminum Association’s aluminum alloy and temper designation system includes code suffixes to denote finish types. -0 is unused mill finish, -1 is clear anodized, -2 is aluminum with a painted black finish.
- NSF 51 – Used for materials in food handling. NSF 51-0XXX denotes various aluminum finishes from mill to clear anodized.
Knowing the relevant color code system for an application helps accurately specify aluminum finishes. Most aluminum suppliers can provide color chips or samples to match to standard color codes.
Silver Aluminum Color Codes
Within these color coding systems, there are specific codes that correspond closest to a silver aluminum finish:
RAL Color Codes for Silver Aluminum
- RAL 9006 – White Aluminum
- RAL 9007 – Grey Aluminum
- RAL 9006 – Silver Metallic Aluminum
RAL 9007 denotes a medium neutral gray shade while RAL 9006 is slightly cooler toned. RAL 9006 has a high gloss metallic finish.
PMS Colors for Silver Aluminum
- PMS 877 – Silver
The PMS metallic silver color 877 is a match for mill finished aluminum.
Federal Standard 595C for Silver Aluminum
- FS 17178 – Aluminum paint
This government specification covers aluminum paint finishes from a dull sheen to high gloss.
ASTM B209 Codes for Silver Aluminum
- -0 – Unused mill finish aluminum
The -0 suffix denotes bare mill finish aluminum with no further coating or finishing. This has a shiny silver-gray appearance.
NSF 51 Codes for Silver Aluminum
- NSF 51-0XXX – Various mill finish to clear anodized aluminum
Codes starting with 51-0 specify uncoated aluminum with a silver luster. Higher numbered codes are clear anodized.
Silver Aluminum Color Properties
Why does bare aluminum have a silver metallic appearance? The intrinsic properties of aluminum metal cause it to reflect light with a pale gray luster.
Aluminum’s Light Reflectance
Polished aluminum has a reflectance of around 90% across the visible light spectrum. This high reflectivity makes it appear like a reflective silver mirror.
Aluminum’s Crystal Structure
Aluminum has a crystalline face-centered cubic structure which interacts with light waves to produce its metallic sheen.
Aluminum’s Natural Oxidation
A thin transparent oxide layer forms on aluminum’s surface when exposed to air. This allows much of the underlying aluminum’s reflectance to show through while muting some of the shine.
Difference Between Mill Finish and Anodized Aluminum
What is the difference between mill finish and anodized silver aluminum?
Mill Finish
Mill finish aluminum refers to the initial untreated surface condition of aluminum coming directly from the rolling mill. It has a bright, shiny, silvery appearance, like a mirror.
Anodized
Anodizing treats the aluminum surface to create a controlled oxide layer that is thicker than the natural oxide layer. A clear anodized finish has a hazy, duller silver look compared to mill finish. It offers better corrosion and wear resistance.
Though both have a silver color, mill finish is high gloss while clear anodized is low gloss. Different aluminum codes specify whether the surface is mill, anodized, or otherwise coated.
Using Silver Aluminum Color Codes
Specifying the correct aluminum finish color code is important for:
Ordering and Manufacturing
Color codes eliminate confusion by providing an exact standard reference for the type and color of aluminum required.
Quality Control
Color codes can be verified to ensure the right aluminum finish is supplied. Visual color comparisons and instrumental testing can match samples to color standards.
Design and Architecture
Architects and designers use color codes in drawings, renderings, and material schedules to communicate the aesthetic appearance of aluminum components.
Regulations and Compliance
Some industries have governing specifications that mandate certain aluminum finishes to meet safety, durability, or performance requirements.
Conclusion
Silver aluminum refers to the lustrous metallic gray appearance of mill finished or clear anodized aluminum. Widely used color coding systems each provide specific codes to accurately denote aluminum surfaces with a silver look. Understanding the distinctions between code options allows proper aluminum selection for a given application. When in doubt, request aluminum color samples to visualize how a particular code will look when specifying a silver aluminum finish.
