Analysis of the Problem of Peeling off of Epoxy Zinc-rich Primer on the Surface of Steel Plate

Recently, a customer inquired about the paint peeling off after finishing the paint on the surface of the steel plate and asked if it was due to welding problems. When we received this question, we immediately thought of the two aspects of substrate treatment and paint selection. As expected, after asking about it, it was indeed a problem with the paint selection.

1. Paint selection

The customer's primer is epoxy zinc-rich primer, which can eliminate the problem of welding, because the weldability of epoxy zinc-rich primer is still good. If the substrate is made of stainless steel, the problem arises because the surface of the stainless steel is very smooth. In terms of the adhesion of the epoxy zinc-rich primer, the epoxy zinc rich primer cannot be used, and it is easy to fall off.

For galvanized pipes, stainless steel, aluminum alloys and other metals with smooth surfaces and poor adhesion, when choosing paint, do not use commonly used paints. Generally, epoxy zinc yellow primer or epoxy zinc phosphate primer is used, phosphating primer can also be used for galvanized pipe. Therefore, if it is not the problem of substrate handling, the peeling off after finishing the paint is usually a problem in the choice of paint.

2. Substrate processing

Epoxy zinc-rich primer peels off on the surface of the steel plate. In addition to the above-mentioned problem of incorrect paint selection, for ordinary steel steel plates, the paint film peeling off is the problem of improper substrate handling. Everyone should understand that the presence of moisture, oil stains, and rust on the surface of ordinary steel plates will reduce the adhesion of the paint and cause the problem of paint film peeling.

In summary, the peeling off of the epoxy zinc-rich primer is generally due to two aspects: the wrong choice of paint or the inadequate treatment of the substrate. Therefore, before buying paint, determine what paint should be used, and clean the steel plate floor before construction, and polish the rust to SA2.5. If you have any other questions, you can consult us. Tianjin Jinhai Special Coatings & Decoration Co., Ltd. will provide you with relevant information and construction guidance for zinc-rich primer.