Reasons for the Cracking of Epoxy Zinc Rich Primer in the Weld

Reasons for the cracking of epoxy zinc-rich primer in the weld
Epoxy zinc-rich primer is a relatively common topcoat product with many main uses. The most common one is steel frame structure. The steel frame structure must be welded by electric welding, and there will be welding. If the paint is improperly used or there is any problem with the spraying, the welding, especially the weld part, is likely to crack the paint.
1. Incomplete metal surface treatment
Among the many industrially produced anticorrosive paints, except for the epoxy zinc yellow topcoat, which can easily solve the smooth surface of aluminum alloy profiles, galvanized steel pipes, etc., most other products are not suitable for use on walls with too smooth surface or Material. If the surface of the welding part is too smooth and the surface roughness is not suitable, the adhesion of the epoxy zinc-rich primer will be greatly reduced. Excessive non-smooth surface can also cause the paint layer to fall off. It is necessary to do a good job of metal surface treatment before the announcement of the project construction, remove the wall or material surface residual welding through, old shiny skin, rust, dust and other appendages, and must be polished to a suitable surface roughness. To ensure that the paint layer adheres firmly and does not fall off casually.
2. The spray paint layer is too thick
The paint layer of epoxy zinc-rich primer is not as thicker as possible. The standard of "suitability" must be grasped. It is neither suitable for too thick nor too thin. As far as the welding position is concerned, the thickness of the paint layer cannot be manipulated compared to other leveling positions. If the spray is too thick, it will be very easy to cause cracks. The key is that the thick paint layer will cause in-situ stress during the dry and dry process, destroy the adhesion of the paint layer, and cause the welding coating to crack.
3. Did not carry out the actual operation of dipping
Before spraying epoxy zinc-rich primer, the welding surface must be dip-coated, especially for fillet welds. Otherwise, after the epoxy zinc-rich primer is sprayed on the wall or material, it will cause backward tensile force during the whole process of drying.