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Six differences between cold galvanized coatings and epoxy zinc-rich primers

Cold galvanized coating and epoxy zinc-rich primer are products with excellent electrochemical anticorrosion performance. They have the characteristics of tough and wear-resistant coating film, strong adhesion ability, good mechanical properties and good anticorrosion performance. They are commonly used outdoor anticorrosion primer products. The difference between the two is mainly reflected in raw materials, dry film zinc powder content, construction points, painting cost, painting cost and so on.

1. Different ingredients

The cold galvanizing coating uses graphene conductive resin and ultra-fine zinc powder (1000 mesh) after special surface treatment as the main raw materials, while the epoxy zinc-rich primer uses epoxy resin and ultra-fine zinc powder (400-800 mesh) as the main raw materials.

 2. Dry film zinc powder content is different

Zinc-rich primer dry film zinc powder content up to 80%. Generally around 70%; The dry film zinc powder of cold galvanized coating can be 96% larger

3. Different construction points

Because the zinc powder content of cold galvanized is more than that of zinc-rich primer, it is necessary to do a closed coating or fog spray intermediate paint in the actual use process.

4. Costs vary

Epoxy zinc-rich primer is a kind of coating with high solid content, dry film thickness of 80μm, cold galvanized coating solid content is low, dry film thickness of 80μm, need two airless spraying.

5. Different application range

Cold galvanizing coating can be used for the repair of hot dip galvanizing and electric galvanizing layers, while epoxy zinc-rich paint is not recommended for coating repair work, suitable for steel substrates, and cannot be used in galvanized steel. When used for outdoor steel structure anti-corrosion coating, cold galvanized coating is mostly used for important and long-term steel structure facilities such as Bridges and towers. Epoxy zinc-rich primer is more widely used because of its lower cost.

6. Steel structure anticorrosion supporting

Epoxy zinc-rich primer matching scheme:
(1) Cost-effective supporting scheme:
Epoxy zinc-rich primer + epoxy iron intermediate paint + acrylic polyurethane topcoat (more than 10 years of service life)
(2) High-grade coating scheme:
Epoxy zinc-rich primer + epoxy iron intermediate paint + fluorocarbon top paint (more than 20 years of service life)

7. Cold galvanizing coating system:

(1) Cold galvanized paint + cold galvanized sealing agent (service life of more than 10 years)
(2) Surface treatment of cold galvanized paint + epoxy sealing primer + fluorocarbon top paint (service life of more than 20 years)

Surface treatment of both

1. Steel: Remove dust and oil from the surface of steel, especially sea salt in the coastal environment. For harsh environment or high anti-corrosion performance requirements using sand blasting rust, up to grade Sa2.5; For general atmospheric environment or can not take sandblasting treatment use power tools to remove rust.
2. Galvanized parts: Dust, oil, sea salt, grinding paper, etc. on the surface of galvanized parts must be removed to remove white rust, to reach St2 level, and for rusted places, power tools are used to remove rust, to reach St3 level.
3. Steel coated with shop primer: clean, dry and in good condition approved shop primer.

Post time: Sep-19-2023