Plating vs. galvanizing.....have I go this right?

Letter 19032

Plating vs. galvanizing.....have I got this right?

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SO galvanizing is not the same as electroplating? It seems that galvanizing combines the, say, steel of a nail with the zinc (resulting in several distinct layers and an outer coating of pure zinc) while electroplating just puts a much thinner coating onto the steel, which can be fairly easily scraped off - right?

Hmm.,

Paul Barnes
- Bensalem, PA., USA

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Wrong- properly zinc plated nails can not have the zinc easily scraped off.

James Watts
- Navarre, Florida

First of two simultaneous responses -- +++

Galvanising, as I understand it, is the coating of a metal with zinc by immersing the article in a bath of molten zinc. Electroplating is the deposition of metal by the pasage of an electric current. Both methods can suffer from adhesion problems if the substrates are not prepared correctly. Remember - in the Bible, cleanliness is next to Godliness, but in metal finishing, cleanliness IS godliness!

However, just to throw a spanner in the works, in Germany, electroplating is known as galvanotechnik and many pieces of electrical equipment are known as galvano...whatevers. Why do we complicate things for ourselves?!

Trevor Crichton
R&D practical scientist - UK

Second of two simultaneous responses -- +++

Galvanizing is a hot-dip process wherein the item is dipped into molten zinc. Electroplating is a process where the part is put into an aqueous ionizing solution and electricity is used to move the metal from an anode to the part being plated.

Most electroplaters do not give too much credence to that multi-layer varying-alloy theory advanced by the galvanizers, but will admit that galvanizing is usually thicker and therefore more corrosion resistant.

Personally I wouldn't worry about the nails; I haven't seen a roof done with those lumpy galvanized roofing nails since roofers started using automatic nail guns many years ago. I've had two roofs done in the last few years and all I worry about are that the flashing and edges were done carefully enough that they won't leak.

Ted Mooney, P.E.
finishing.com
Brick, New Jersey

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Galvanizing comes in two forms, one is hot dip which is as it sounds dipping the part in molten zinc. The other is electro galvanized which is a plating process. The hot dip is used when higher film builds are required.

Ronald Zeeman
- Brampton, ON, Canada

Dear Reader, please --

Answer or follow-up on this subject (in non-commercial fashion).