Galvanization Explained: Hot-Dip vs. Electro-Galvanized Wire

Why the coating matters more than the steel

Almost every wire product in a fencing catalogue is built on the same base material: mild steel. What actually determines service life is the zinc coating applied over it, because zinc corrodes preferentially to steel — it sacrifices itself to protect the wire underneath, right up until the coating is exhausted.

There are two common ways to apply that coating, and they are not interchangeable specs.

Hot-dip galvanizing

Hot-dip draws the wire through a bath of molten zinc, forming a thick metallurgical bond between the zinc and the steel surface. The coating is uneven at a microscopic level but substantially thicker than electro-galvanizing produces, which translates directly into a longer service life in continuous outdoor exposure — the scenario almost every fencing product faces.

Electro-galvanizing

Electro-galvanizing deposits zinc through an electroplating process, producing a thinner, smoother, more uniform coating. It is well suited to indoor or lower-exposure applications and gives a cleaner finish, but the thinner coating means it wears through faster under sustained weather exposure than hot-dip.

What this means for a fencing spec

For anything installed outdoors and expected to stay in the ground for years — boundary fencing, field fence, chainlink, barbed wire — hot-dip is almost always the right call, and it is the default coating across most of the Medvaan range. Electro-galvanized wire has its place in lighter-duty or indoor applications where coating thickness matters less than finish and cost.

A quick way to sanity-check a supplier’s claim

Ask for the coating weight, not just the word "galvanized." Coating weight (measured in grams per square metre) is the actual number that determines how long the zinc layer will outlast weather exposure — "galvanized" alone tells you the process, not the thickness.