Which is a Better Process Electroplating or Galvanizing for CS Piping?

Electropolishing is applied to stainless steel piping for hygienic/dairy/pharmaceutical use; it won't do any good at all on bog-standard carbon steels, as these are not even suitable wetted materials for potable water.

Galvanised carbon steel is a considered choice for compressed air.

Consider using copper or plastics for potable water instead in the smaller diameters, or even cement-lined carbon steel for the larger diameters. If all else fails, thin-walled stainless can be an economic option for larger sizes, though electropolishing is rarely needed as the water has biological protection applied in the form of ppm-levels of chlorine, usually.

End-user specifications can dictate the choice, and where available, follow them.

GA, - do you think maybe he was looking for a comparison of two different galvanising techniques - hot dip or electroplated and just got the words wrong?

Greetings:

There is another option of applying zinc, that would be to use thermal spray technology. Hot dip galvanizing uses a process where after you activate the surface in chemical baths followed by dipping the part into molten zinc. It is very effective and has been used for years.

Another option is to use thermal spray technology to melt the zinc in a thermal spray gun, atomize it, and spray the part to be coated with the molten zinc. It is like spraying paint, but you are spraying molten zinc. The method of melting the zinc is either with combustion gases or electric arc. If you would like to know more about it, there is a short article at this link:

Thermal Spray Zinc, Alternative to Hot Dip Galvanizing

If you have more questions, there is a phone number at that site that you can call.

ThermaSprayGuy

Galvanizing forms an intermetallic zincate which gives very good adhesion of the coating to the substrate and allows thicker coatings and longer lasting protection than other methods.

If the coating is too thick, the strength of the coating eventually exceeds the strength of the bond and separation of the two is possible under some loads.

Some of the zincate usually remains and provides some protection.

Electroplating and spraying don't have the same bond and cannot be satisfactorily applied as thicker coatings.

Electroplating gives a smoother coating which doesn't hold "crud" as readily and can be less prone to growth of various molds. (These are not supposed to be able to grow on the zinc, but they do, especially in the tropics).

Hope these ramblings are of some help.