# Anodising vs Powder Coating: Choosing an Aluminium Finish

> Anodising grows a hard oxide layer out of the aluminium itself by electrolysis; powder coating sprays a polymer onto the surface and bakes it on. One is part of the metal, the other sits on top of it — which is why they age in completely different ways.

## Why it matters on a project

Finish is usually treated as an appearance decision and priced as a rate. It is
actually a durability decision that determines how the building looks in ten
years, and it is close to impossible to correct once the facade is installed —
recoating aluminium in situ never matches factory quality.

## How they compare

| | Anodising | Powder coating |
| --- | --- | --- |
| Nature of finish | Oxide layer grown from the metal | Polymer film applied on top |
| Can it peel? | No — it is part of the substrate | Yes, if pre-treatment was poor |
| Colour range | Limited: silver, bronze, champagne, black | Effectively any RAL shade |
| Colour consistency | Batch variation is real and visible | Excellent, consistent between batches |
| Abrasion resistance | Very high | Moderate |
| UV / chalking | Does not chalk | Depends entirely on resin grade |
| Coastal performance | Strong | Strong with PVDF, weak with polyester |
| Typical relative cost | Higher | Lower to comparable at PVDF grade |
| Repair on site | Very difficult | Touch-up possible, rarely invisible |

## Common mistakes

- **Accepting "powder coated" without naming the resin.** Standard polyester and
  PVDF to AAMA 2605 are different products with very different lifespans. The
  specification must name the grade, not the process.
- **Not batching anodised profiles.** Anodised colour varies between production
  runs. Profiles for one elevation should come from one batch, and that has to be
  planned before ordering.
- **Ignoring pre-treatment on powder coating.** Adhesion is entirely dependent on
  chromate or chrome-free pre-treatment. Coating over poorly prepared aluminium
  fails at the edges within a few years.
- **Choosing on rate alone.** The cheaper finish that fades in five years costs
  vastly more than the difference, because correcting it means access equipment
  across a live building.
- **Forgetting the fixings.** Stainless fasteners against a coated surface, and
  dissimilar metals in contact, cause staining and galvanic problems that are
  blamed on the finish.

## Where Hagerstone uses it

Both finishes run through our facade scope across curtain wall, doors and
windows, cladding and architectural elements. Through **Viva Composite Panel**
we work with ACP, solid aluminium, honeycomb, louvre and rainscreen products in
500+ shades with fire-retardant grades and **PVDF coatings** — the coating class
worth specifying where colour has to hold outdoors.

## Standards referenced

Anodic coating thickness and quality classes follow **IS 1868**. High-performance
organic coatings — the PVDF class — are specified to **AAMA 2605**, which is the
grade to name when weathering and colour retention matter.

## Frequently asked questions

### Which lasts longer in Indian conditions?

Anodising generally wins on abrasion and on coastal or heavily polluted sites, because the finish is integral to the metal and cannot peel. A high-grade PVDF powder coat to AAMA 2605 is not far behind and holds colour extremely well. The finish that actually fails soonest is a cheap polyester powder coat, which chalks and fades within a few years of direct Indian sun.

### Why is anodised colour so limited?

Anodised colour comes from dye absorbed into the porous oxide layer or from the metal itself, so the palette is essentially natural silver, bronzes, champagne, black. Powder coating can match effectively any RAL shade. If the architect has specified a brand colour, powder coating is usually the only route.

### Can anodised and powder-coated aluminium be mixed on one elevation?

Technically yes, and it is best avoided. The two finishes reflect light differently and age differently, so an initially acceptable match diverges over years. Where both are unavoidable, separate them by element — for example all glazing framing in one finish, all louvres in the other — rather than mixing them in the same visual plane.

## Sources

- [IS 1868](https://standards.bis.gov.in/website/published-standards/department-wise) — Anodic coatings on aluminium
- [AAMA 2605](https://fgiaonline.org/) — High-performance organic coatings

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Source: https://hagerstone.com/glossary/anodising-vs-powder-coating