Don’t use oil or alkyd paint on galvanized metal: Sherwin-Williams says the zinc reacts with the alkyd binder and the paint peels, and Benjamin Moore says not to use alkyd paints or oil-based primers on it at all. Use a primer whose maker names galvanized, such as Rust-Oleum Stops Rust Aluminum Primer, Zinsser BONDZ or Sherwin-Williams All Surface Enamel Latex Primer.
Why paint peels off galvanized
Sherwin-Williams’ galvanized guide: “Alkyd or oil paints that are applied to galvanized metal will adhere initially but quickly fail. The zinc of the galvanizing will chemically react with the paint’s alkyd binder, creating a ‘soapy’ film (known as saponification) on the galvanized metal, causing the coating to peel.” It adds that new galvanized metal is usually coated with oil or a passivator, and paint over that “will peel quickly.”
Benjamin Moore’s galvanized guide says galvanized metal has a zinc coating to prevent rust, and: “Do not use any alkyd-based paints or oil-based primers on galvanized metal.” Sherwin-Williams says “Most acrylic coatings will adhere directly to cleaned galvanized metal.”
Primers whose makers name galvanized
| Primer | Galvanized line | Base | Topcoat or recoat |
|---|---|---|---|
| Rust-Oleum Stops Rust Universal Bonding Primer (quart) | “interior/exterior surfaces such as galvanized steel, non-ferrous metals” | Water-based acrylic | Topcoat after 1 hour; best topcoated within 7 days |
| Rust-Oleum Stops Rust Universal Bonding Primer (aerosol) | Data sheet: “galvanized steel, wrought iron railings”; see the label conflict below | Solvent-based (acetone and other ketones) | Second coat or topcoat any time; two hours before two-part epoxies |
| Rust-Oleum Stops Rust Aluminum Primer | “a specially formulated base coat for aluminum or galvanized metal” | Water-based acrylic | Recoat after 1 to 3 hours; brush-on topcoat in 1 to 2 hours, aerosol in 16 to 24 hours |
| Rust-Oleum Professional Aluminum Primer | Also “a specially formulated base coat for aluminum or galvanized metal” | Water-based acrylic | Topcoat after 2 to 4 hours |
| Zinsser BONDZ | “galvanized steel” | Acrylic | Data sheet: topcoat in 3 hours; page: recoat in 1 hour |
| Zinsser Bulls Eye 1-2-3 (brush) | “galvanized metal”; label: “Primes galvanized metal” | Water-base | Topcoat in 1 hour |
| Zinsser ALLPRIME | “Excellent for galvanized and other metals” | Not stated here | Recoat in 1 hour |
| Zinsser SmartPrime | “Use SmartPrime to prime uncoated ferrous metals, galvanized metal, aluminum” | Water-base | Recoat after an hour |
| Sherwin-Williams All Surface Enamel Latex Primer | “iron, steel, aluminum, and galvanizing”; Sherwin-Williams’ galvanized guide suggests it for exterior galvanized | Acrylic | Touch 1 hour; recoat 4 hours |
| Sherwin-Williams Multi-Purpose Latex Primer | “Galvanized Metal” | Latex | Recoat at 1 hour |
| Benjamin Moore HP1100 Acrylic Metal Primer | “ferrous metal, galvanized metal, aluminum, other non-ferrous metals” | Acrylic, water reducible | Recoat 2 hours |
| Benjamin Moore HP1750 Waterborne Bonding Primer | “galvanized metal and stainless steel” | Waterborne | Recoat at 2 hours |
| Benjamin Moore INSL-X Stix | “galvanized metals” | Acrylic urethane | Recoat 3 to 4 hours |
From each primer’s data sheet, label or page. Benjamin Moore’s galvanized guide also names its Ultra Spec HP Acrylic Metal Primer for unpainted galvanized; we didn’t read that primer’s data sheet.
Label conflict, Rust-Oleum Universal Bonding Primer aerosol: its page and both data sheets list galvanized steel, and so does the English panel of the 2016 aerosol label. A Rust-Oleum data sheet for the 12 ounce spray (ATO-95, revised 2017) also says it “may be used on interior or exterior surfaces to include galvanized steel.” The Spanish panel of that 2016 label says not to apply it “en metal galvanizado” (on galvanized metal). We’d read the can you buy, and if it still says both, pick another primer from the table for galvanized.
Products whose makers say not on galvanized
- Rust-Oleum Painter’s Touch 2X (primer and colors) and Universal spray paint: “Do not apply to galvanized steel.” Universal’s label front says “ANY SURFACE,” but its own directions say not on galvanized metal.
- Rust-Oleum Stops Rust Clean Metal and Rusty Metal Primers, and Stops Rust Protective Enamel: not for galvanized steel or metal, their data sheets say. So do the data sheets for Rust Reformer and Automotive Self Etching Primer.
- Zinsser Bulls Eye 1-2-3 aerosol and Cover Stain aerosol: each names “non-galvanized metal.” The brush version of Bulls Eye 1-2-3 does name galvanized, so check which one you have.
- Benjamin Moore HP1320 Universal Metal Primer: “Not recommended for non-ferrous metals such as galvanized, aluminum.”
- Rust-Oleum Cold Galvanizing Compound is for touching up damaged galvanized steel, and its data sheet says “Do not topcoat with an alkyd finish. If a topcoat is desired, use a latex coating.”
Prep: new or weathered
New galvanized: Sherwin-Williams says the oil or passivator must be completely removed. A water-soluble cleaner removes oily residue but not passivator; it suggests testing a cleaned spot with copper sulfate solution, and if the spot doesn’t turn black, the passivator is still there and must come off by SSPC-SP7. Benjamin Moore says to wipe new galvanized with white vinegar, then degrease with Corotech Oil & Grease Emulsifier and rinse with fresh water.
Weathered galvanized has a white powdery residue, Benjamin Moore says, and needs a thorough degreasing. Sherwin-Williams says a weathered galvanized surface can develop white rust, which must be removed, with a wire brush, a stiff brush or an abrasive pad.
Solvents: Sherwin-Williams says “Most hydrocarbon solvents, including mineral spirits, leave a thin layer of residue that leads to adhesion failure,” and to use a water-based cleaner instead. Zinsser’s Bulls Eye 1-2-3 label says “Clean new galvanized metal with solvent cleaner.” Those are two makers; we’d follow the cleaning line of the primer you use.
Sanding: Benjamin Moore says “Do not sand galvanized metal, as the sanding process can damage the metal surface.” Sherwin-Williams’ All Surface primer data sheet says to “Remove all corrosion with sandpaper, wire brush, other abrading method” and prime the same day. We’d remove only white rust and corrosion, with the wire brush, stiff brush or abrasive pad Sherwin-Williams’ guide names, and not sand sound zinc.
Already painted: Benjamin Moore says there is no need to prime previously painted galvanized metal. Sherwin-Williams warns that painting new, oily or passivated galvanized in cold or very humid weather can make the paint wrinkle and lose adhesion.
EPA says that if your home was built before 1978, it is more likely to have lead-based paint. If you sand or scrape old paint yourself, EPA says to use its lead-safe work practices, and not to attempt to remove lead-based paint yourself. See epa.gov/lead.