During the preparation process, every steel is carefully inspected to make sure the surface is fully prepared for a quality finish. Below is a list of some materials the cleaning chemicals used prior to galvanizing cannot remove or have a great deal of difficulty removing:
• Heavy/thick deposits of wax or grease
• Weld slag and other welding flux residues
• Crayon markers/oil-based paints
• Epoxies, vinyls, and asphalt
• Heavy or extremely adherent mill scale
• Heavy lacquer
• Weld splatter and anti-splatter
• Sand and other impurities on castings
These materials should be removed from the metal prior to it being delivered to the galvanizing plant. SSPC and NACE have a variety of commonly used standards for abrasive blast cleaning, hand cleaning, and power tool cleaning, effective at removing these materials. Abrasive blasting is usually necessary on castings to remove sand and other impurities from the casting process. Alternatively, different products can be used on the steel or iron which are compatible with the hot-dip galvanizing process to reduce the need for blasting or hand/power tool cleaning. For example, using uncoated electrodes avoids the problem of depositing flux on the metal during welding, and galvanizing-safe markers are available that dissolve in the cleaning baths used in the galvanizing process. Different types (specifications) of pipe can be ordered that are free of mill coatings such as varnishes, lacquers, or oils.
Seattle Galvanizing will contact you to get approval to go ahead with the blasting service.
Our blasting service is only available to our hot-dip galvanizing customers.