Is this Zinc Pest?

[Larry C]

LOL Wow what a reply..and No Scott not at all....You thoughts are honorable. When I first started collecting these beauties..I was all into the history..then I became Steel addicted like a junkie..and only saw what was in front of me. No Please do not misunderstand my post Once in awhile..I always like to throw out that reminder to everyone. Its not the first time. You`re on top of your motivation . Best Larry

[avenger]

Ha....you gotta love the internet. It makes it so hard to interpret conversation sometimes.

It's an excellent reminder Larry, one I must have needed or I wouldn't have felt I had to reply in a 10 page thesis!

[StefanM]

For those that don't know what zinc pest is: Zinc pest corrosion

[Frogprince]

For those that don't know what zinc pest is: Zinc pest corrosion

I like the article that StefanM posted but would not pick on Zamak per se myself as the culprit (also known as Mazak in the UK and made in multiple alloy grades/combinations tailored for specific purposes), but instead impurities - especially lead. With the military buildup/war causing reductions in skilled zinc workers in Germany which as I seem to recall was a guild(?) with a limited membership (that got smaller). And in any case the end result being an alloy known as Kriegsmetall. Which had the problems described in the article having seen especially some late dagger parts and other items crumble to the touch. And IMO even the better quality zinc can sometimes have a problem where too much moisture is concerned - especially if the surface finish is compromised which is not uncommon for example with thinly plated parts. Best Regards, Fred

[Wagriff]

Zinc also has, of course, the most annoying habit of Eating gold and silver coatings over time. How many times have we seen a CCC, for example, with the question of "What grade?". The 1930's Zinc was a hard but brittle metal that had many many problems associated with it, but the war's pinch made it a necessity. It was Cheap and filled the need for quick inexpensive metal alloy. Many medals and awards simply did not Come in any other metal than Zinc. A shame, as they are getting harder and harder to find in pristine conditions as time passes. Someday....? Who can say what will be left for the future collectors?

[Danmark]

The key word in the article is "intercrystalline" - which basically means that what is seen on the outside is a result of what is happening inside at the grain boundaries of the zinc ( or mazak or zamak ) cast granules. Like inter-granular corrosion, it is the death knell for a cast product and is a ticking time bomb in all of these items as Wagriff has pointed out.

Dan

[Glenn66]

Well, nothing lasts forever so enjoy what you can while you can. Certainly these artifacts regardless of material will survive you and me by a long way.

[gerrit]

Scott,

we have discussed this matter by PM already, and as i stated before: it is not reverseable and cant be stopped.
The impurity's in the metal are there, mostly lead, even if its grained down till healthy material, sooner or later it will happen again, perhaps on another spot.
You can slow it down by store in into a very dry enviroment, but the process itself is unstopable.

This is a whats called a "Hidden defect" and sold under the terms of WAF forum, so i would send it back & ask for a refund.

Regards,
Ger

[Frogprince]

In a relatively dry indoors environment, and at this late date not seeing signs of corrosion, I’m not really losing much sleep myself with my period zinc based artifacts. But if corrosion has already started as the other members have stated - that’s IMO another matter (that also applies to steel especially if it’s an active red rust).

Only somewhat off topic, they are also the zinc hilted sabers (click to enlarge) that exhibit the obvious signs of corroding zinc periodically turning up in the hands of collectors. And I can name East and West Coast dealers who in the not too dim past have sold “Silver - SS” sabers to collectors for considerable sums that were not what they were supposed to be. Instead being late (post 1935/brass) sabers made with zinc hilts that are minus the original gold-gilt that they left the factory with (also aluminum - but that’s a different topic).

Said zinc hilted sabers also oftentimes getting a craft store “silver out of a bottle” bath that can acquire the black patina of silver or silver plating. Which works for a while, but then the white residue of corroding zinc bubbles up from underneath. Which in the example posted here it appears to have a lacquer or clear finish of some kind which was probably applied to try and keep the metal underneath from reacting to moisture in the air. Obviously it didn’t work - and presumably the purchasers took the dealer’s word at face value. Best Regards, Fred