Just a few more zinc pest photos.....commonplace these days

This has happened in the past, MTH has always made good when these things happen. Zinc Alloys in the Far East are not always as pure as they should be.

Scott Smith

JINIS:: what catalog/year is your P5? I have one and it has never been out of the box from 2008, set 20-5636. Also who did you contact at MTH for the replacement shell?I will open mine this weekend to inspect. Scott can you answer any of the above questions?

Ouch- that is too bad - but this is the downside of building models out of low cost metals, rather than brass or plastic

Just opened mine up and I have the same issue. Same Cab Number. My question would be where else are we going to see this issue. I have more than a few items never opened due to lack of space which will not be an issue in the new house.

I have 20-5582-1 #4748 from the 2006 catalog, no evidence of any issues forming so far.  Sounds like I dodged this bullet.

To the guys who have this issue.   Any chance your trains may be in a basement?

I would send an e-mail to their customer service listed on their website. Kirsten took care of my issues a few years back. Her husband recently took a job in Texas, so she is no longer at MTH.

Scott Smith

What a beautiful model.  I have the streamlined version - I will go look at it.  Nice photos - sorry you have bad castings.

Hate to bust any bubbles, but locomotive shells aren't the only victims of poor quality control in the Far East casting facilities; my Lionel I-12 cabeese had several truck castings disintegrate in the past.

Even more disturbing are several MTH plastic diesel shells that seem to become brittle with time-attaching posts that attach the shell to the frame disintegrate and need unscheduled post repairs.

Marty: Mine have been in a finished, insulated and environmentally controlled(heated and cooled with a dehumidifier) basement for years still currently are. I have never had any issues like this in the past.

That’s a shame to see this. A new shell is one thing but who will dismount and remount all the added details and lights? May be a difficult job. Hopefully MTH will take care of everything. 

Is that bad metal or bad paint job?  You can get a look like that if the surface wasn't properly cleaned and prepared before painted.  Either way it's good to hear MTH making it right.

It's impurities in the zinc alloy.  It can certainly be worsened by being in a moist environment, but the source of the problem is the impurities.  I posted some detailed info on how this happens from a metallurgical sense in the other thread.  Good info.

We have a P5 4741, not from a set.  No major issues so far.

Unfortunatly, if an engine has zinc pest there isn’t anything that can be done to stop it.  Perhaps proper storage can slow the process, but the real factor is the impurities in the mix.     

bob3 posted:

Ouch- that is too bad - but this is the downside of building models out of low cost metals, rather than brass or plastic

 

There is nothing wrong with zinc. It is used all over the world for thousands of things, some critical, that have nothing to do with models. That the impurities (commonly lead, as I understand) are real and damaging is undeniable, but what do you think those hundreds of thousands (millions?) of Post-War Lionel steamer shells were made from? Not brass and not plastic, and a more stable bunch of zinc castings I can't imagine.

Lionel had the problem with some Pre-War zinc castings (notably in some of the scale 700E pieces), but the problem was solved so long as the production was domestic; American Flyer also suffered from it (and badly warping plastics) both Pre- and Pot-War, I believe.

I don't care for zinc because I modify things, and I find it an annoying metal to work. But that's my problem. The pest problem has affected me also, so far not in the crumbling locomotive sense, but I imagine that a few of those on my shelves are quietly self-destructing. I have few locos in the box.

Also, while I have numerous MTH locos, partly because I run TMCC and not DCS, I may not have the MTH inventory that some do. I sense a bit more of it with that brand (not an MTH bash).

All brands have been affected, as we all know. And none of this helps the guy with the crumbling loco, as above. It's just a terrible sight to see a nice loco - I love it - do that.
   

This is what happens when there is no true/actual Quality ASSURANCE.  Quality Control is no substitute.  Two different animals.

That really sucks. 

On a prototype sidebar: prior to retirement, it's been reported that P5's had cracking main driver frames.  Pennsy would paint them heavily with black paint to "fill" the cracks to hide them from FRA inspectors.  So, in the twilight of their careers, they always seemed to have freshly painted underframes and severely weathered bodies.

Unfortunately, the P5 zinc pest thing is more like art imitating life.

Fred

You can find anything on Wikipedia….

Click here: to read their information.

Zinc Pest or Zinc Rot

Number one cause: While impurities of the alloy are the primary cause of the problem, environmental conditions such as high humidity may accelerate the process.

Gary

PRRronbh posted:

This is what happens when there is no true/actual Quality ASSURANCE.  Quality Control is no substitute.  Two different animals.

Not of they do thier jobs. Assurance is just a preventative offshoot of failures of QC. I.e. identified management of Q.C. labor. The fault can actually like elsewhere; it identifies where an ax may fall if labor is the continual issue.

I got hit with the Rot with my K-Line HW passenger sets. BUT.....K-Line was still with us and they said if I\d swap out the trucks myself they'd send replacements. They did not want them sent in...but that was fine....took me a few weeks to get them all done.

Zinc rot is a problem in Chinese model manufacturing primarily because the central production facilities rely so heavily on subcontractors for parts production.

In China, some of these subcontractors are described as garage operations, meaning they are small shops or one-man operations. Unfortunately, too many of them practice poor quality control, especially when it comes to casting zinc parts properly.

Usually, the bad parts are couplers, truck sideframes or freight car frames. Locomotive shells aren’t usually victimized. But, as is the case in this thread, not always.

The problem is that train production is considered a low-volume endeavor in China, so the use of subcontractors is inevitable. Since there is no way to inspect a part for improper zinc processing immediately after it has been cast, the problem really can’t be fixed by quality control inspections at the factory. The subcontractors have to take responsibility beforehand.

Fortunately, as D500 alluded to above, the problem is very uncommon. And I think it is laughable to call zinc a cheap metal, especially given how properly casted zinc products have outlasted most forms of alternative metals.

As for plastic, manufacturers turned to its use in the postwar era because it was cheaper to use for castings. Drop your 15-pound locomotive to the concrete floor from four feet high and tell me how superior it is.

Three pairs of Weaver metal archbars ( which l had new in the box), crumbled when l wanted to wheel a kit bashed caboose recently, one after the other. Was any of this diecasting done in Korea, before the move to China, l guess after being priced out?

Scott: I have sent three emails to MTH thru the web site and have yet to get a response. Kristen was the lady that helped me last time and it a shame she is gone. Does anyone have any contact information at MTH on this issue. Eric from another Zinc Pest thread with the same P5a was having the issue and MTH reached out to him directly to resolve his issue and I was hoping that I could get the same service.

Just spoke to MTH and very nice gentleman name Nathen. I sent him the photos of my P5a Zinc Pest issue and he will forward to a service tech and get back with me and what MTH will do and what is expected from me. Time will tell.

Lead has been added to zinc forever on galvanizing lines, purposely.  It enhances spangle formation during solidification of the zinc. Most companies phased out lead and replaced it with antimony because of intergranular corrosion on products that sit too long before processing.