Coated aluminium
Aluminium with an anodic or organic finish on it. The finish is the thing at risk, not the metal — and marks from mistreating it may be permanent.
What not to do
Citric acid is unsafe on Coated aluminium
Unsafe
Do not do this. The risk is established, and it is described below.
Evidence
Supported
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That aggressive alkaline or acid cleaners must never be used on aluminium finishes, and that marks resulting from mistreatment may be permanent. (states this directly)
Acetic acid (vinegar) is unsafe on Coated aluminium
Unsafe
Do not do this. The risk is established, and it is described below.
Vinegar included. The prohibition is on acid cleaners as a class rather than on any particular acid.
Evidence
Supported
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That aggressive alkaline or acid cleaners must never be used on aluminium finishes, and that marks resulting from mistreatment may be permanent. (states this directly)
Sodium carbonate may damage Coated aluminium
Best avoided
The available guidance advises against this.
The alkaline half of the same prohibition. Soda crystals are the domestic form most likely to reach a garden table.
Evidence
Supported
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That aggressive alkaline cleaners must never be used on aluminium finishes, and that alkaline materials allowed to dry on the metal will quickly corrode anodic coatings. (states this directly)
Mild abrasion may damage Coated aluminium
Best avoided
The available guidance advises against this.
Evidence
Supported
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That excessive abrasive rubbing must not be used because it can produce an undesirable appearance or adversely affect the finish, and that strong solvents or abrasive cleaners can damage painted surfaces. (states this directly)
In detail
Most aluminium a domestic reader touches is coated: patio furniture frames, window frames, radiator covers, appliance trim. The finish is either an ANODIC coating grown into the surface or an ORGANIC one sprayed and cured onto it, which is what a powder-coated frame has. Either way the coating is the surface, and it fails differently from the bare metal underneath. The association guidance is direct about limits. Never use aggressive alkaline or acid cleaners on aluminium finishes. Named acids and fluorides are excluded on anodised surfaces. Strong solvents and abrasive cleaners damage painted surfaces, and excessive abrasive rubbing will alter the finish. Marks resulting from mistreatment MAY BE PERMANENT, which is the sentence that decides how cautiously to start. The method escalates from nothing: water at moderate pressure, then mild detergent, rinsed and dried. Its test for mild enough is good — a soap rated safe for bare hands should be safe for the coating. One condition is specific to outdoors and missing from almost all consumer advice: do not clean a hot, sun-heated surface. Reactions on hot metal run fast and unevenly, and the streaking may not be recoverable.
Properties
Sensitivity
- Acids
- Sensitive
- Alkalis
- Sensitive
- Heat
- Sensitive
- Abrasion
- Sensitive
- Porous
- Not applicable
“Not known” means nobody has established this, not that the material is unaffected.
What works
Detergent is safe on, in specific conditions, Coated aluminium
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- mild only — the association's test is a soap or detergent rated safe for bare hands
- water at moderate pressure first; detergent only if soil still adheres
- rinsed thoroughly with clean water and dried
- in the shade, never on a hot sun-heated surface
- test-clean a small area first, and identify the finish before choosing a method
Precautions
- Test on an inconspicuous area first
- Rinse thoroughly afterwards
- Do not apply to a hot surface
Evidence
Supported
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That cleaning starts by flushing with water at moderate pressure and escalates to mild detergent with sponging, that soaps ruled safe for bare hands should be safe for coated aluminium, that stronger detergents must be spot tested, that the surface is rinsed and dried, and that hot sun-heated surfaces must not be cleaned. (states this directly)
Sources for this page
Sources
AAMA 609 & 610-02: Cleaning and Maintenance Guide for Architecturally Finished Aluminum
American Architectural Manufacturers Association (AAMA), 2002 · Standards body
Relied on for: That the finishes covered are anodic and thermoplastic and thermosetting organic coatings, that aggressive alkaline or acid cleaners must never be used on them, that strong solvents and abrasives damage painted finishes, that marks from mistreatment may be permanent, that cleaning starts with water then mild detergent, and that hot sun-heated surfaces must not be cleaned. (states this directly)