Fence glossary · Materials
Powder coat
A dry finish applied as electrostatically charged powder and then oven-cured, so it fuses into a continuous shell bonded to the metal rather than sitting on it as a film. It is the standard finish on aluminum and ornamental fence, and the reason those systems never need repainting.
The process is what makes the difference. The extrusion is cleaned and chemically pretreated, then sprayed with a charged polyester powder that clings to the grounded metal and wraps around edges and inside corners that a brush or a spray gun would miss. It goes through a cure oven, the powder flows out and cross-links, and what comes off the line is a single uniform shell with no runs, no thin spots and no solvent evaporating out of it later.
Compared with wet paint on metal, the practical outcomes are that the film is thicker and more even, the colour does not chalk or flake, and there is nothing to repaint on a maintenance schedule. Washing it is the whole routine. Darker colours run hotter in direct sun than white or bronze, which is worth knowing on a long south-facing run but is not a durability problem in this climate.
The one thing to respect is that the shell is only continuous while it is intact. A field-cut picket, a drilled hole for a hinge or a deep scrape from a mower exposes bare aluminum at that point. Aluminum does not rust, so this is cosmetic rather than structural, but cut ends get capped or touched up as a matter of course. On steel components the same break in the coating is a genuine corrosion start, which is why hardware on a coated system should be coated or stainless rather than plain.
