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Powder coating

Powder coating electrostatically applies polyester or epoxy powder, cured at ~200C. Covers AS 3715 durability classes, coastal limits, and duplex systems.

By Chalkline. Last updated 11 June 2026. Verified 11 June 2026.

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Powder coating is a dry finishing process: charged powder particles are electrostatically attracted to the grounded workpiece, then oven-cured at roughly 180-200 degrees Celsius for 10-20 minutes, cross-linking the resin into a hard film (verified 2026-06-11, machine4aluminium.com). No solvent is used. Typical film thickness is 60-80 microns on architectural aluminium.

Polyester vs epoxy

Polyester is the standard exterior formulation: UV-stable, resists chalking and colour fade. Interpon’s 600/D1000/D2000 series and Dulux Duralloy are polyester-based (verified 2026-06-11, Interpon AU).

Epoxy resists chemicals and bonds well to metal, but chalks under UV. It suits interior work: plant rooms, shelving, internal steelwork. Epoxy primer plus polyester topcoat is used for demanding exterior or industrial applications.

AS 3715 and durability classes

AS 3715:2025 governs powder coatings on architectural aluminium. The 2025 revision aligns durability classes with AS 4312 corrosivity zones (C2-C5), replacing blanket distance rules with a microclimate framework covering humidity, pollution, and orientation (verified 2026-06-11, AGWA). Class 2-9 buildings need L2 or higher; C4/C5 sites require at least 2 g/m2 surface preparation before coating.

AS 4506 covers powder coating on steel and its pre-treatment requirements for galvanised steel.

Coastal warranty limits

Warranty distance limits vary by product tier. Dulux Duralloy requires >100 m from the high tide line; Electro/Charisma require >10 m; Fluoroset may be specified closer to harbours (verified 2026-06-11, Dulux Alumi Shield). Warranties require an accredited coater; salt water must be cleaned immediately.

Duplex system (powder over galv)

Powder coating over hot-dip galvanised steel forms a duplex system for severe environments: zinc sacrifices first, powder coat slows zinc consumption. AS 4506 requires chemical pre-treatment of the zinc surface before coating for all exterior and coastal applications (verified 2026-06-11, E-static). See galvanising and steel beams.

Also known as: Powder coat, thermoset powder coating.

Category: Finishes / Metal coating.

See also

Last updated: 2026-06-11. Verified: 2026-06-11. Quarterly review for currency.

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