Oftentimes a masking material is applied to steel prior to galvanization. The masking agent prevents galvanization from occurring on the steel surface to which it l is applied. This can be useful for several reasons. The Steel Supply Company most commonly sees masking materials used on threaded bolts. If a precise fit is required between the threading and its nut, the additional width that galvanization creates within the threads can cause an issue. While this is a common use case for masking material, there are a myriad of other applications.
Masking material includes both adhesive tapes, like duct tape, or chemical compounds, like Maskote Zinc Stop-off. There are several different products sold in each category, however, The Steel Supply Company generally recommends, and exclusively sells, Maskote Zinc Stop-off.
The reason The Steel Supply Company prefers Maskote Zinc Stop-off is because of its efficacy in use and price point. In a 2010 study, the AGA found that adhesive tapes failed to prevent galvanization in most circumstances and specifically when used in conjunction with threaded bolts, whereas chemical compounds, such as Maskote Zinc Stop-off were successful. An added benefit is has been also shown to be effective when given only an hour of curing time.
The key in using Maskote Zinc Stop-off is to be sure the steel surface is clean of any debris or fluids, even dried fluids. The best cleaning agent The Steel Supply Company has found is lacquer thinner. Once clean, the steel substrate allows for full adhesion of the Maskote Zinc Stop-off. This prohibits galvanization between the zinc coating and steel surface, while ensuring that the zinc will bond to non-covered areas.
The per ounce cost of Maskote Zinc Stop-off is much lower than other chemical comparatives. While other substances, like caulks, are much less expensive, they are not as easily applied, and other chemical solutions that function like Maskote can be as much as 50% more expensive.
If you have any questions about masking material, Maskote Zinc Stop-off, or how to best facilitate galvanization for your steel fabrication project, don't hesitate to reach out to one of The Steel Supply Company's representatives who can assist you.