Powder coat vs anodise vs zinc plate vs raw: choosing a finish

Same part, four finishes

A finish does two jobs at once — it decides how the part looks and how long it survives. The four we reach for most pull those levers differently. Start from where the part lives and the choice usually makes itself.

Belt and braces for outdoor steel: zinc first, powder over it (a duplex system). Corrosion life beyond either alone.

Powder coat — colour and toughness

Electrostatic powder, baked hard in an oven, on steel or aluminium. It’s the go-to when you want a specific colour and a tough, even film — any RAL, matt to gloss, texture optional. Protection is a barrier, so it’s only as good as the pretreatment under it: get that right and it lasts years outdoors.

Anodise — for aluminium only

Anodising grows a hard oxide layer into the aluminium rather than coating on top, so it can’t chip or peel and keeps the metallic look. It’s thin, technical and dimensionally stable — right for heatsinks, trim, and architectural aluminium. Colour range is limited next to powder, and it does nothing for steel.

Zinc, galvanising and raw

For bare steel that must not rust, zinc is the answer — plating for indoor fasteners, hot-dip galvanising for structural steel that lives outside. It’s sacrificial: the zinc corrodes so the steel doesn’t. Raw or passivated finishes leave the metal’s natural face — fine for stainless and aluminium indoors, a rust clock for bare steel.