NASCLA Accredited Commercial General ContractorFinishesEasy
A contractor is preparing to apply a finish coat of paint to a newly installed galvanized metal door frame. Which type of primer is most appropriate to ensure proper adhesion and corrosion resistance?
- AShellac-based primer
- BZinc-rich epoxy primer
- CLatex acrylic primer
- DOil-based alkyd primer
Show answer & explanationAnswer & explanation
Correct answer: B. Zinc-rich epoxy primer
Galvanized metal requires a specialized primer to prevent adhesion issues and corrosion. A zinc-rich epoxy primer chemically reacts with the galvanized surface, providing excellent adhesion and sacrificial corrosion protection.
Why the other options are wrong
- A. Shellac-based primers are primarily used for stain blocking and sealing, not for galvanized metal adhesion.
- C. Latex acrylic primers may not provide sufficient adhesion or corrosion resistance on galvanized surfaces.
- D. Oil-based alkyd primers can react poorly with galvanized metal, leading to adhesion failure and blistering.
Zinc-Rich Epoxy Primer
A specialized primer containing a high concentration of zinc dust, used for priming galvanized steel and other ferrous metals.
- Provides excellent adhesion to galvanized surfaces.
- Offers sacrificial cathodic protection against corrosion.
- Prevents paint delamination and blistering on galvanized metal.
Memory trick: Zinc-rich primers ZIP up galvanized metal for a perfect finish.