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Paint Peeling problems on Prepainted Galvanized Steel Sheets

2003

We have been facing problems of paint peeling on Prepainted Galvanized Steel sheets on our project. The problem has started occurring after we have profiled (rolled formed) the sheets and then supplied them to the site. The peeling is starting to appear 3-4 months after the material has been stored on site or installed. In some cases, the paint is peeling with the guard film on the prepainted galvanized steel sheet. We would like to know the following: Why would this problem have occurred? Any solution for fixing this problem?

The specification of the material was:

Thickness: 0.50
Galvanization: 275 gsm
Paint coating: SMP

Thank you.

Apoorva Shrivastava
- New Delhi, India

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2003

We are processing the galvanised sheets through various pre-treatment processes. Such as degreasing, phosphating, primer coating base coating and top coating or finish coating. Among these, base coat have the role to hold top coat as well as primer coat and primer coat have the role to adhere sheet metal as well as the base coat. The selection of the paint as well as coating thickness of the paint has to be optimised for avoiding paint peel off.

Tapan Kumar Rout
- Jamshedpur, India

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2004

We Having Powder coating Plant with Seven tank Process (e.g., KOD- Degreasing- Water rinse - Activation - Phosphating - RO Water Rinse - DM Water Rinse). We are doing Paint on Galvanised Zinc Coated Sheet Z-12. Please tell me if Phosphating is necessary on Zinc Coated Sheet? Any other Process available ?

Rohit Patel
- Kadi, Gujarat, India