Please list the causes of problems with the adhesion of coatings to zinc and galvanized steel substrates.:
1. The new zinc surfaces are smooth, oily or greasy, or even dirty. With insufficient cleaning and too little roughness, problems with adhesion to the substrate are often encountered.
2. Na starych powierzchniach cynkowych osadzają się produkty korozji. If they are not thoroughly removed, Coatings that are applied later come off due to insufficient adhesion.
3. Gdy na podłoże cynkowe nakłada się lakiery alkidowe, zinc with the oil components of the coating materials creates zinc soaps. They reduce the adhesion of subsequent coatings. Because alkyd varnishes contain oily substances, the coatings of these varnishes crumble over time.

How should the zinc substrate be prepared for the coating??

For the preparation of the zinc substrate prior to coating application, washing with a surfactant ammonia bath using a synthetic corundum nonwoven has proved to be appropriate.. Do 10 l of water should be added approx. 0,5 l 25% aqueous ammonia solution (the 1,25 10% aqueous ammonia solution). Two caps of the surfactant should be poured into this bath. As a result of grinding, on wet non-woven fabric made of synthetic material, with the addition of said bath, foam forms, which should remain on the prepared surface for approx. 10 min. At the end, rinse the cleaned surface with plenty of clean water. Under no circumstances should steel fibers be used for grinding.