Zamac rot

I've heard some other modelers discussing Zamac (what the frames are usually made of) rot.  It is also known as Zinc Pest: https://en.wikipedia.org/wiki/Zinc_pest

I don't think there is anything that can be done, aside from not using the material in the first place.

Zamac/mazak rot

I believe it's models made within a certain period.  

You should check all your models as it can crack the bodies when the chassis expands and rots.  Therefore you can replace the chassis and don't lose the whole model.

White Metal Problems

Hi,

This has been reported for quite a few years. The problem starts with the creation of white metal, pot metal, zamac, or whatever you want to call it way back when. Besides zinc being common to most of these, the rest of the "alloy" has been described as "whatever the manufacturer happened to have on hand!" In other words there are lots of variations on what the actual compositions were. Nonetheless, over time it is said that some of this crystalizes internally, in time, and there is a "natural" warping of the material which induces cracking and eventually breakage. I do not believe there is any preventative nor cure. I once thought that painted models seemed to have a better chance of survival, but I too have some terrible examples with major deterioration of well painted loco frames.

I read an article on the web of a gentleman transferred to India who had an old Rivarossi loco of great sentimental value (his Dad's if I remember correctly)  whose white metal cylinders had badly warped, cracked and broke into pieces. He made a rubber mold of the undeteriorated half, ground up the white metal parts into a powder, mixed it with epoxy, and recreated the loco cylinders with literally the original material! It was an amazing and interesting story.

Sorry for this report. Nonetheless... have fun! 

Zamac rot

A lot of the older O scale parts had this problem, I've heard it was from lead contaminated zinc in the alloy....DaveB

Manufacturers rediscovering zinc pest

Over the years, I'd noticed zinc pest mostly in older models, generally predating about 1970. (Original) Aristocraft die cast models were some of the worst for this. It became less of an issue from the mid-1970s on, though still appeared from time to time, but nowhere near as often as it used to.

MDC/Roundhouse seemed to have figured out how to minimize this through the 1980s and 1990s, but I've had a couple of the more recent-ish Athearn-era Roundhouse brand gondolas develop severe problems from the frames distorting due to this. They swell to the point of sagging to nearly touching the rails. At that point, pretty much all one can do is find an older kit and use its frame as a replacement.

One thing that can contribute to zinc pest is incautiously re-using metal scrap. This is one of the obvious ways that the current batch of manufacturers is likely to be rediscovering zinc pest.

The manufacturer to blame

I blame the manufacturer/importer.  This is a know problem from years ago.  There are solutions that help, but like everything else quality control is essential.

Frankly, I would pay extra if they used brass - of course you still need QC.

Paul

Alloys

Geoff hit it right on the head. It's whatever the factory can throw into the pot to stretch the material. Why make a hundred items when you can make two? Remember the melamine in the Chinese chocolate thing? Zinc alloy is a great example of this and will vary from run to run.

I know two separate people who manufacture overseas and both have to have someone keep an eye on what goes into their product. Unfortunately unions are driving more and more manufacturing away.

Casting Rot

Have been able to at least slow the process down,by wire brushing the area,then repainting it

Walters Mainline had the "Rot" from the factory in China, Lots of P-32BWH's and -8 40B's were victims

of "Casting Rot" . There are some modelers that have built a new underframe from brass and

salvaged the drive and bodyshell off the remains of the old frame.

Sink Pest

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

Rich

Patriotic set from Micro-Trains

This is a copy of a email sent to Micro this week

A week ago I brought this set from a VERY reputable SELLER via ebay (Australia) He is the Australian secretary of the local NMRA.
The set was sealed and unopened. So  old but new was expected.
It arrived to me a few days later and I was horrified.... the engine was a LifeLike made in China and was suffering from ( I found out later)  It is called Zinc pest (from German Zinkpest), also known as zinc rot and mazak rot, is a destructive, intercrystalline corrosion process of zinc alloys containing lead impurities,
 ......amazing stuff, the plastic next to the metal seemed affected too.
I appreciate this is 20 odd years old and maybe much older.
I raise this occurrence for your scientific file and in the hope you may send me a new engine, why you sold Lifelike engines as yours is beyond me..But I don't know USA laws..
Keep well and safe regards Kenn

Just curious to ask if anybody else had this problem. Fascinating to see metal breaking up

Zinc rot

I recently found two of my N scale Intermountain F3 A loco's had extreme zinc rot, one having burst the loco shell and the other deformed to the extent I can't even remove the shell from the frame.

Kudo's to Intermountain; after contacting them, they offered to replace frames and shells gratis.

Steve

Bowser as well!

I have an old Bowser Pennsy 2-10-0 that I bought in kit form back in 1975 direct from Bowser mail order. Same horrible zinc disintegration. Started in the water pump casting and progressed to the cylinders and frame. I always thought that Bowser were one of the better quality manufacturers of the day - not any more.

My first experience with Zinkpest

I had never even heard of this issue until yesterday.  I received an old (new old stock) Walthers Trainline FB-1 from a reputable dealer whom I have dealt with before.  It looked great and I didn't even notice the cracking in the frame.  I put in on the track and within a few seconds one of the drive train dog bones fell out.  I was a bit surprised, but I have put DCC decoders in many Walthers Trainline loco's so I figured it would be no problem to fix this one.

I flipped it over and noticed the cracking, but just figured it was a paint issue.  I tried to pry the tabs away to get the shell off but it wouldn't budge.  I also took off the couplers and coupler pockets in case there was something there.  Still no luck.

I got online and found a post describing the issue I was having, the cracking, the bulge in the end of the shell (picture #3), and difficulty in removing the shell.  That's when I knew I was in trouble.

I ran the blade of an X-acto knife along the inside edges hoping to separate whatever was holding it.  Nothing.

The post mentioned holding the fuel tank while prying.  I got a firm hold on the fuel tank and began prying one side, making very little progress.  I turned the loco over and began prying the other side and that's when the fuel tank disintegrated.

That's where I stopped.  I now have a $55 worthless piece of scrap pot metal.

I used to think Walthers was one of the top manufacturers of HO trains (I have 29 other Walthers loco's with no issues - that I'm aware of yet), but this experience has caused me to rethink my position.

What amazes me is that the Zinkpest issue has been known since 1923 and was theoretically eliminated in the 1960's by using higher quality materials.  What this tells me is that the model railroad manufacturers are still using sub-standard materials and passing known junk to their customers.  IMHO, *any* manufacturer that produces trains suffering from Zinkpest is a sub-prime manufacturer.

Yesterday I lost all respect for the model railroad manufacturers.  A simple problem to fix, but they choose not to fix it in order to save a few cents profit at the expense of their customers.  A truly classic case of built-in obsolescence.

"Yesterday I lost all respect

"Yesterday I lost all respect for the model railroad manufacturers. A simple problem to fix, but they choose not to fix it in order to save a few cents profit at the expense of their customers"
 

  The manufacturers don't really have control over what the producers put in the zinc pot. If you have 29 engines with no problems and 1 bad one that doesn't sound like Walthers is trying to use bad zinc to save money, sounds more like a bad batch that they didn't know about til years later? ......DaveB

Contact Walthers

Did you report this to Walthers' customer support?  Most manufacturers will replace the defective unit under warranty if you still have the receipt from the vendor.  I've never had a problem with Walthers that they did not quickly resolve.  Also, it's probably not Walthers' practices at fault here.  It's most likely the Chinese factory sneaking in sub standard metal, hoping that by the time issues show up they will be in the clear. 

. . .

Best of luck with Walthers.

They do not offer a Life Time Warranty  like say Bachmann does.  The warranty is 1 year and items produced before 2006 are not accepted for RA

This Zinc Pest does not pop up in the first year or two.

But you have little to loose by trying to see how they stand behind the product they manufacture.  This is a clear manufacturing defect that renders the engine totally useless in time.

Marc

Hold your horses

Whoa there, hold your horses. Bad batches happen to the best of manufacturers. Your conclusion is only valid if every loco of the same age and type as yours has the same issue.

Let’s take this a step at a time before we start making huge wide sweeping proclamations, okay?

Next step is to contact Walthers and see if they’ve got a replacement. Offer to pay for the replacement and shipping (should just be a few dollars). If they’re smart, they’ll decline the payment, but even if they don’t, you should have a new frame for just a few dollars.

. . .

Guess people will start pulling the engines of the shelf and examining them closely. These are all 2005 / 2006 from browsing the web.researching more on this, there are still people that think this was all resolved in the 60s. More and more videos of Zinc Rot on You tube. with frames just falling apart.  What I find hilarious is people going to great pains to fix  then  but cant address the zinc rot itself, so what is the point.

....

Zinc pest happens to all manufacturers some of the time because Zamac is dependent upon the variables at the point of alloy production and you will not know which runs have zinc pest and which are free.  Even runs within the same year, some are fine, others suffer.

This page has the best description and cause: temperature fluctuations.

Zinc pest - The Brighton Toy and Model Index (brightontoymuseum.co.uk)

I am rather happy I have kept my trains in climate controlled storage, but that means due to winter activity where my unit was not heated may mean I may have significant zinc pest in my collection as time goes on.  We will see.

Wonder how extensive this issue is

Over the last 18 months I have been selling off most of my HO items from various manufacturers & various release years.  Items from the late 80’s to 2013.  Fortunately none showed any sign of this issue.  
When I was fixing & selling, I would see the problem.  It was particularly prevalent in certain models of a specific manufacturer.  The Bachmann GP40’s of a particular frame design comes to mind.  This was one of their first attempts at all wheel drive.  Pre Spectrum.  The bottom metal frame was notorious for this rot.  Later models from them did not suffer from that problem.  There were a few other specific models that it was so prevalent that I put it on my list to avoid.  
I wonder if this is a outcome of lack of corporate memory.  The desire to reduce costs a driving the alloy mixtures & the factories where they are making this items don’t have the details on what to avoid.  I certainly hope it is limited in scope.  

Quality problems come in waves

Hi,

as disgusting as the problem itself is, it is even more disgusting how this and similar quality problems come in waves.

The issue came up in the 1960ies and was solved then. It may have re-appeared in the 1980ies and was solved. Now, obviously it has re-emerged on production runs from the 2000s...

Same thing in other places... Issues that were solved twenty years ago suddenly re-appear...

Actually, recently I had a discussion with a younger colleague. He told me about the latest trend. I just kept thinking about how we looked at that same trend (different name, though) about twenty years ago. Made me feel old.

I think it is very annoying that we have to repeat the exact same problems that were solved twenty years ago... ust another indication that "Human 2.0" has not been invented yet.

Good luck in repairing the locos!

I need to check into some of

I need to check into some of my storage boxes, as storage temps are uncontrolled in this part of the world.

Alloys

Scary Thoughts

I had thought this problem had been solved years ago. I was SURPRISED to hear of such problems in this more modern era, ....and affecting a number of manufacturers.

The frames are the backbone of our model engines, and if these go bad we are left with a worthless piece of trash. Many of us realize that a lot (most) of these importers do NOT import an inventory of parts for their model trains, thus we are likely to never get a replacement part even if the sellers were willing to honor a warranty.

This could definitely have me second guessing the purchase of any second hand locomotives. WOW

  "this is what to expect

It's not just a communist problem, when I was modeling in O scale many of the old US manufactured models had this problem. It's a contamination of the alloy problem.....DaveB