Thickness Requirements for Zinc Rich Epoxy Primer

Zinc rich epoxy primer has become the most commonly used anti-corrosion and anti-rust primer for steel equipment and facilities. However, many customers still have questions about how thick the zinc rich epoxy primer should be brushed or how many times it should spray. Ruisen is here to answer the question "How thick should the zinc rich epoxy primer be?" according to the coating engineering experience at home and abroad as well as the relevant standards.

What are the factors that affect the thickness of the zinc rich epoxy primer?
The thickness of the zinc rich epoxy primer should be determined comprehensively in accordance with the service life of the anti-corrosion coating, the surface treatment of the steel, and the corrosion factors. According to the coating regulations in ISO12944-2007, the steel coated with zinc rich epoxy primer should have a surface treatment to reach the standard of Sa2.5 or St3 and the roughness of 50μm. (Grinding is required to increase roughness.)

When the zinc rich epoxy primer is used as an anticorrosive primer, the recommended dry film thickness is 60μm, which is most convenient for airless spraying. Brushing is generally only used for small area spraying. When air spraying is used, it can be sprayed twice.

The zinc rich epoxy primer is used as a shop primer. It is only used for temporary anti-corrosion coating of workpieces. If there is a need for welding, the recommended dry film thickness is 25 μm, which is applied by air spraying.

According to the practical engineering experience, the domestic zinc rich epoxy primer is generally low in zinc powder content, and the surface treatment requirements are not up to standard. It is recommended to increase the dry film thickness to 70-80 μm, especially for outdoor long-term steel structure corrosion protection and decoration engineering.