We manufacture hand tools and sometimes need to strip zinc diecasted parts that have been epoxy powder coated. Normally, it is a small quantity (500-1,000 parts). Our painter, an outside contractor, has not been able to come up with a method that does a good job. He normally uses a bake-off oven to strip steel parts and racks, but the zinc parts cannot tolerate the 700F heat required to remove the coating. Any suggestions would be appreciated. J.K.
Several stripping methods come to mind. Your contractor can use either hot or cold chemical strippers that are capable of removing the powder coating. These strippers must be handled cautiously to ensure their safe application and must be disposed of properly and in accordance with local EPA rules.
Molten salt baths are easier to use and are much quicker than chemical strippers. They will remove the powder coating completely without residue. However, the cost for this equipment is higher than even bake-off ovens.
Lastly, your contractor can use a grit blast system to remove the powder coating. There are many types of grits that can remove the powder coating without affecting the zinc substrate.