What Does Sweep Blast Cleaning Mean?
Sweep blast cleaning is an abrasive blast cleaning method used to remove loose material and roughen the surface of a substrate prior to the application of a paint or coating. This technique is primarily used for the preparation of galvanized surfaces before the addition of a second protective coating layer. Sweep blast cleaning is so-called because the abrasive blasting is done using a fast pass, or light sweeping method.
Sweep blast cleaning is also known as abrasive brush-off blast cleaning.
Corrosionpedia Explains Sweep Blast Cleaning
The purpose of sweep blast cleaning is to deform, not remove galvanized metal. The light sweeping action serves simply to increase adhesion of the topcoat intended to go over the galvanized surface. Sweep blast cleaning should therefore be aggressive enough to clean and profile the surface while being gentle enough to prevent excessive removal of the zinc coating.
This method is especially crucial for fabricators in duplex coating systems. The sweep blast cleaning process is acknowledged by several standards, including the ASTM D6386 and the ASTM D7803, as an acceptable surface preparation method for hot-dip galvanized surfaces.