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'''Painting metal''' is a different discipline from painting wood or drywall: bare metal gives paint nothing porous to grip, and ferrous metals actively fight the finish by rusting underneath it. Success depends almost entirely on surface prep and primer selection.

== Know Your Metal ==

{| class="wikitable" style="width: 100%;"
|-
! Metal !! Key Problem !! Primer
|-
| '''Steel / iron (ferrous)''' || Rust || Rust-inhibiting metal primer; rust converter on pitted areas
|-
| '''Galvanized steel''' || Zinc coating rejects most paints || Clean with degreaser; galvanized-compatible (acrylic) primer — never oil primer on fresh galvanizing
|-
| '''Aluminum''' || Oxide layer, poor adhesion || Self-etching primer or acrylic bonding primer
|-
| '''Copper / brass''' || Patina, usually decorative || Often left unpainted; degrease + bonding primer if painting
|-
| '''Previously painted metal''' || Old failing paint, chalking || Sound paint: scuff and topcoat; failing paint: remove, spot-prime bare metal
|}

== Preparation ==

Prep is 80% of a metal paint job:

# '''Remove loose rust and failing paint.''' Wire brush, [[Sanding|sand]] (80–120 grit working to 180–220), or use a drill-mounted wire wheel. Heavy rust may need a rust converter, which chemically transforms residue into a paintable surface.
# '''Feather sound paint edges''' so old and new surfaces blend.
# '''Degrease completely.''' Metal collects oils — from manufacturing, handling, and weather protection. Wipe with denatured alcohol or a dedicated degreaser; rinse and dry. Skipping this is the top cause of peeling on metal.
# '''Scuff glossy surfaces''' with 220 grit or a fine abrasive pad so primer can key in.
# '''Prime immediately.''' Bare steel begins flash-rusting within hours in humid air. Prime the same day you finish prep.

== Choosing Paint ==

* '''Oil-based/alkyd enamel''' — the traditional choice for steel: hard, moisture-resistant film; slower dry, see [[Oil-Based Paint]]
* '''Acrylic (water-based) enamel''' — flexible, non-yellowing, fast recoat; modern DTM ("direct-to-metal") acrylics are excellent for most residential metal — see [[Latex Paint]]
* '''[[Spray Paint]]''' — ideal for railings, furniture, and intricate shapes; many aerosols combine rust-inhibiting primer and enamel
* '''Sheen''' — gloss and semi-gloss shed water and wipe clean, which suits metal; see [[Paint Finishes]]

== Application ==

# Apply '''rust-inhibiting primer''' (brush, roll, or spray) to all bare metal; two coats on outdoor items. Respect the primer's topcoat window.
# '''Thin coats.''' Metal is non-porous, so paint sits on top and sags easily on vertical or curved surfaces. Two to three thin coats beat one heavy coat.
# Use a quality [[Paint Brushes|brush]] for profiles, a foam [[Paint Rollers|roller]] for flat panels (lay off to avoid stipple and [[Brush Marks|brush marks]]), or [[Spray Paint|spray]] for complex shapes like wrought iron.
# '''Watch the weather outdoors.''' Metal surface temperature matters more than air temperature — paint applied to sun-heated metal blisters, and cold metal below the dew point condenses moisture under your paint. Aim for a dry, mild, overcast day. See [[Exterior Painting]].
# Allow '''long cure times''' before hard use — enamel on metal can take weeks to reach full hardness.

== Common Projects ==

* '''Railings and wrought iron''' — wire-brush rust, converter on pitting, rust-inhibiting primer, two coats gloss enamel; aerosol works well on ornate sections
* '''Steel entry doors''' — degrease, scuff, DTM acrylic or alkyd enamel; follow the panel sequence in [[Painting Doors]]
* '''Metal outdoor furniture''' — [[Spray Paint]] with primer-in-one rust formulas gives the smoothest result on tubular frames
* '''Radiators''' — use heat-rated paint; paint cold radiators and let cure fully before heating
* '''Gutters and downspouts''' — degrease (new galvanized gutters may need months of weathering or a vinegar wash), acrylic primer, exterior acrylic topcoat

== Common Mistakes ==

* '''Painting over rust''' — the rust keeps spreading and lifts the new paint within a season; remove or convert it first
* '''Skipping degreasing''' — invisible oil films are the most common cause of wholesale peeling on metal
* '''No primer on bare metal''' — topcoat alone cannot bond to slick metal or stop corrosion
* '''Oil-based primer on fresh galvanized steel''' — the alkyd reacts with zinc (saponification) and peels off in sheets; use acrylic
* '''Heavy coats''' — runs and sags are worse on non-porous metal than any other surface
* '''Painting hot or damp metal''' — blistering and adhesion failure

== Safety ==

* Wear '''gloves and eye protection''' when wire-brushing or grinding rust
* Use a '''respirator''' when spraying or sanding — metal primers and old coatings can contain harsh solvents and toxins
* '''Old painted metal may contain [[Lead Paint|lead]]''' — industrial and pre-1978 residential metalwork frequently does; test before sanding or grinding
* Ventilate solvent-based products well; see [[Painting Safety]]

== Frequently Asked Questions ==

=== Can you paint directly over rust? ===
No — paint over loose rust fails quickly as corrosion continues underneath. Remove loose rust mechanically, then either take the surface to sound metal or apply a rust converter that neutralizes remaining residue, followed by rust-inhibiting primer. "Direct-over-rust" paints still require removing loose, flaking rust first.

=== What primer should I use on metal? ===
Match the primer to the metal: rust-inhibiting primer for steel and iron, self-etching or acrylic bonding primer for aluminum, and an acrylic (never oil-based) primer for galvanized surfaces. On previously painted metal in sound condition, a scuff [[Sanding|sand]] plus bonding primer is enough.

=== Do I need special paint for metal? ===
You need an enamel rated for metal — either alkyd or a modern direct-to-metal (DTM) acrylic — rather than ordinary wall paint, which stays too soft and holds moisture against the surface. For outdoor metal, exterior-rated enamel with a rust-inhibiting primer underneath is essential.

=== Why is my paint peeling off metal? ===
Almost always one of three prep failures: grease or oil left on the surface, no primer (or the wrong primer for that metal), or painting over glossy old paint without scuffing. Galvanized metal painted with oil-based products also peels due to a chemical reaction with the zinc coating.

=== Is spray paint or brush better for metal? ===
Spray gives the smoothest, most even film on intricate or curved metal (railings, furniture, hardware) with no [[Brush Marks|brush marks]]. Brushing works fine on large flat or simple surfaces and builds a thicker film per coat. Many pros prime with a brush for film build, then spray the topcoat for appearance. See [[Spray Paint]] for technique.

[[Category:Exterior Painting]]
[[Category:Painting Techniques]]
[[Category:DIY Painting]]
[[Category:Surface Preparation]]

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