For the Steel Fabricator and Construction Trades Hot Dip Galvanizing is the standard zinc coating to protect against rust. One alternative, when a finer surface finish is required is Electroplating.

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.

In the last post about galvanized vent hole plugs, we covered the difference between aluminum and zinc vent hole plugs and the circumstances in which each one is best suited.

All vent hole plugs are designed for the same purpose, to seal the vent and drainage holes made in a steel component during the galvanization process. While their functionality is simple, the choice of whether to use aluminum or zinc vent hole plugs can be more complicated.

Maskote Zinc Stop-Off is the best solution we have found for keeping Hot Dip Galvanizing Zinc off areas of steel where it is un-wanted. Figure 1 shows tests that were performed in  our factory. The Zinc Stop-Off was applied, the steel sent out for galvanizing, and when returned wire brushed to remove any residue or caked on zinc.

Vent Hole Plugs in Drilled and Punched Drain Holes vs. Plasma Cut Holes

Stops Zinc from adhering to selected areas of steel during the Hot Dip Galvanizing process.

Galvanized Vent Hole Plugs, whether Aluminum or Zinc, will seal themselves very tightly with normal installation. The slight taper in the body allows the plug to be driven into the hole like a wedge. Each successive hammer strike drives the plug in slightly further and makes it a little tighter. As well, both Aluminum and Zinc Vent Hole plugs are relatively soft, malleable metals. While being driven in, they conform to the minor irregularities of the hole. In this way with normal installation, the plug is sufficiently tight to remain in place for the life of the fabricated steel.