Zamak Attack

[Showme]

  The latest news in the saga of the zinc pest issue. You might want to check your Walthers Evans Coil Steel Cars. I was sorting my freight fleet over the weekend and noticed this car had a bit of curve to it. New in the box, I took it out to find this. I have several dozen of these cars and fortunately, this is the only one to do this.

Bob

[jagged ben]

Wow, that ended up curvier than the lady on the Coca Cola ad underneath.

[brokemoto]

OUCH!

I am glad that I do not model that era.  I do,however, have to worry about IM F-units' getting zirmac rot.  I check mine frequently.  Nothing has shown up Y-E-T.  I did sell most of mine several years past, prior to my being aware of the problem.........sorry that this happened to Original Poster.. 

[Showme]

  I do not have any of the F units but I do have 17 of the Tunnel Motor units. Thanks to the post about the IM frame problem, I checked them all and one was coming apart. Also, thanks to that post I caught it in time to remove the shell before it exploded with the frame. Keeping a close eye on the rest of them.
  That Coca Cola sign was on one of my buildings but I used the wrong kind of glue and it eventually fell off. I'll get around to glueing her back on one of these days.

Bob

[randgust]

You'd think by this time this would be ancient history.    It certainly was endemic on the old Rivarossi (Atlas) stuff.   I had an original Atlas FM C liner that blew apart right at the motor, glued it up with styrene and goo, operational POS anyway so no great loss.
But I also had a nice Rivarossi 4-6-2 that was in a 'return' box that was brand new with frame swelling, I milled out the axle slots slightly as those were binding, and it ran quite well, for a while, finally split off everything in front of the cylinder saddle.  I chopped it up to make my D16 in a new frame.

That was 50 years ago, and we're still seeing this today in relatively new production.   Hard to believe that they still, for economic or other reasons, manage to cook this stuff up with enough impurities to still blow up like this.   It's like the plague - once you figure out it's from the fleas, no excuses to not know what to do.

[John]

It's not just trains .. most metal things from China like gazebos and other similar items are made from inferior metals ..

[peteski]

It's not just trains .. most metal things from China like gazebos and other similar items are made from inferior metals ..

That's my thought exactly.  Poor metal quality control. Not sure why someone dinged you a down-vote for that statement. 

[John]

Not sure why someone dinged you a down-vote for that statement. 

Ehhh .. it's not important to me ..  we can disagree.   You can search the forum and find examples of the metal used in the atlas C55 frogs and points ..

[spookshow]

That's my thought exactly.  Poor metal quality control. Not sure why someone dinged you a down-vote for that statement. 

I'm sure the Chinese have plenty of AI bots cruising around the web looking for things to disagree with. Or maybe it's just somebody at Intermountain 

-Mark

[John]

https://en.wikipedia.org/wiki/Zinc_pest

From Wikipedia, the free encyclopedia

Zinc pest (from German Zinkpest "zinc plague"), also known as zinc rot and zamak rot, is a destructive, intercrystalline corrosion process of zinc alloys containing lead impurities.[1] While impurities of the alloy are the primary cause of the problem, environmental conditions such as high humidity (greater than 65%) may accelerate the process.[2][3]

It was first discovered to be a problem in 1923,[1] and primarily affects die-cast zinc articles that were manufactured during the 1920s through 1950s. The New Jersey Zinc Company developed zamak alloys in 1929 using 99.99% pure zinc metal to avoid the problem, and articles made after 1960 are usually considered free of the risk of zinc pest since the use of purer materials and more controlled manufacturing conditions make zinc pest degradation unlikely.[2]

[Showme]

I guess the Chinamen don't know that because the Walthers cars are quite a ways post 1960.

Rivarossi didn't know it either because just like randgust, I have had a LOT of the early Atlas stuff crumble.

Bob

[wm3798]

I've had several Rivarossi steamers come across my workbench that had swelling and crumbling, but also a remarkable number of them that are just fine.
The good news is there are lots of parts donors as a result.

It is odd that this very well known issues is still rearing its ugly head nowadays.

Lee

[peteski]

I've had several Rivarossi steamers come across my workbench that had swelling and crumbling, but also a remarkable number of them that are just fine.
The good news is there are lots of parts donors as a result.

It is odd that this very well known issues is still rearing its ugly head nowadays.

Lee

I think the longevity of the pest-prone alloy depends on the storage conditions.  If the item was in a dry environment and not exposed to extreme temperature, it will not probably not rot for a long time.  If it is then exposed to more humid and war environment, it will start rotting away.  Kind of like a time bomb.  And of course the more modern examples must be made from a contaminated alloy due to use of sub-par raw materials.

[ntex]

My examples have always been stored in their original boxes when zinc rot was discovered. Are there any examples where the object was out of the packaging when zinc rot was found?

[Doug G.]

Although the environment can play a role in the problem, its effects are miniscule compared to that of basic metal formula. None of my old Atlas/Rivarossi locos that developed it were ever stored in a damp environment.

Doug