Zinc Plated vs Galvanized

[duncan_ellison]

I can locally find ZINC plated high test chain at a reasonable price. Shure looks nice and shiny.

Can anyone tell me if / why I should NOT use this in preference to galvanised chaion of the same spec ?

Duncan

[craigsmith]

Zinc plated is much thinner and more vulnerable to chipping than HDG, in addition to faster wear. HDG forms several iron-zinc alloy layers under the pure zinc which are very hard and durable. It's a false economy to use anything other than HDG for anchor chain, galvanizing doesn't last as long as would be ideal as it is.

[zoombats]

Yeah, a thing called rust!

[perchance]

Zinc is a sacrificial metal. The thicker it is the longer it will last.

[GordMay]

Originally Posted by craigsmith

... It's a false economy to use anything other than HDG for anchor chain, galvanizing doesn't last as long as would be ideal as it is.

HDG = Hot Dip Galvanized

[bruce smith]

Those zinc molecules actually get IN there a little bit when the HOT part happens!

[duncan_ellison]

Just trying to understand ..... I thought Galvanizing and Zinc was the same material (I do understand that the process of getting in on the chain is different) - so it boils down to the thickness - plating is a lot thineer - right ?

Duncan

[bruce smith]

I think,
In galvanizing, the piece is put in a tank of molten zink until the steel core reaches the same temp as the zinc. The steel molecules move apart a bit and the zinc molecules get in, a little bit. Galv weakens steel a little, especially thin metal.
Plating is a process of zapping it with 'lectricity to attach zinc.

The galvanizing is far superior to plating, cept for something like a "tin" roof, which is too thin to be galvanized.
Also something to consider ,as it concerns the life of chain, modern "hardened " /hi test chain rusts faster ,the galvanizing wears out quicker. Similar to a chisle rusting easier than a screwdriver, cuz the steel is hardened.

[NotQuiteLost]

With HDG, the zinc actually becomes a part of the outer shell of the chain iron. You can't knock it off (give it a try with a hammer), but with the plated stuff often times it's fairly easy to chip pieces of it off, and one weak link is all it takes for a big problem.

[GordMay]

There are three common ways to apply zinc: electroplating, mechanical plating, and hot-dip galvanizing.

Electroplating is the least expensive operation for thin coatings, mechanical plating/galvanizing is the most economical for coatings of medium thickness, and hot-dip galvanizing is the most economical for thick coatings (which give the best corrosion protection).

See ➥ http://www.hdgasa.org.za/infoSheet/sheet1.pdf

[bstreep]

Originally Posted by bruce smith

The galvanizing is far superior to plating, cept for something like a "tin" roof, which is too thin to be galvanized.

A "tin roof" is actually a hot-dipped galvanized roof. Used to be in the steel business, and we made "roofing tin". In the case of light gauge roofing the zinc is a large part of the total weight of the panel.

For chain... I'd want Hot Dipped. Both the electroplating and hot dipped methods, if done correctly AND if stored correctly, produce a chip-free end product. If you have zinc chipping off, you stored your chain in a locker with no drain and/or no circulation.

Contrary to popular belief, you can NOT store galvanized roofing outdoors - the first rain will ruin it. A galvanic reaction starts up as soon as it gets wet.