Self Destructing MTH Torpedo

Thom, Sorry to see what has happened to your trains. There have been many posts on here about MTH's die-cast problems so I'm sure people will be able to provide you with plenty of similar stories.

More Zinc rot!

Try contacting MTH. They are not likely to honor the warranty, but hopefully there have been productions runs of similar tenders, and they can sale you a new shell. Is the frame and trucks ok?

They helped me out a while back when the trucks on one of my Premier 70ft Madison Mail cars crumbled in my hands.

Hope this helped.

Richard

Thanks for the note. To say it is a disappointment is an understatement. Dad really enjoyed his trains, he invested a lot and he took great care of them. I have a never-run Millennium gold plated Hudson that is showing signs of disintegrating as well. It is frustrating because the postwar Lionel my son and I enjoy just keep going and going.

 I've been out of the O gauge scene for the last decade or so and I'm not trying to fuel the MTH VS. Lionel debate. I'm just looking for some answers and see if anyone else is having this problem and if there is anything I can do to prevent it. I am surprised in this day and age (and considering the cost of some of these models) that the metallurgy is suffering from quality issues.

Thom Cholowski

Saskatoon,Saskatchewan

Canada

I agree with Richard - call MTH and see what they can do. They are certainly aware of the problem. They had a number of issues with zinc castings made around the same time as your RK tender. The usual causes are impurities in the alloy and/or incorrect temperature for the pour. 

Apart from that, keep your eye on eBay. All kinds of oddball and one of a kind parts show up there on a totally unpredictable basis. 

Tom,

Yes, It is sad to know that many of the expensive modern trans we have been buying for the past 20 years will never have the longevity of our" over engineered" post war trains made by Lionel. To borrow a title from the Moody Blues, our post war trains will be passed on" To Our Children's Children's Children" and possibly beyond.

Richard  

Hello Richard

 Thanks for the note. To prove your point succinctly -

Here is my (then 2 1/2 year old) son enjoying some post war Lionel.

https://www.youtube.com/watch?v=DKEbafzKVxc

and our (his?) Conventional Classics 726 passenger set.

https://www.youtube.com/watch?v=_eGPnc92nbo

Thom Cholowski

Saskatoon,Saskatchewan

Canada

Thom,

My small collection was packed up for a few years, and so far I've had zinc pest problems with one MTH and one Lionel engine.  In both cases the products were well out of warranty, and both companies were very helpful in providing replacement parts.  Contact them.

But I have to admit it was an eye opener, and I've reconsidered how much money I'm willing to spend on trains.  Can't see myself spending thousands of dollars on die-cast that goes bad in 5-10 years.

Alan

Thom:

I had the exact same problem with that same tender.  MTH replaced the shell for free. It happened several years after I bought it so it was definitely out-of-warranty.

Bill

Is the 'zinc pest' only a problem with modern die cast? I thought this had been a problem for many, many years going way back with some items?

I was, then it seemed like we beat it, but now corner cutting, cheaper materials, and general sloppiness appear to have brought it back on the scene.  At least that's what the research (cursory...) I did seems to indicate...

Way back, I believe.

I'm not a real pre or post war historian, but I think it might have been old Dorfan trains where there are a limited number of surviving examples due to a problem similar to this.

-Dave

I've dubbed the zinc pest malady Dorfan's Disease; Flyer 3/16ths O gauge models from right before WW 2 are susceptible to this as well.

Yeah, zinc pest goes back to the dawn of time. 

The metal alloy in question is ZAMAC, which is an acronym for Zinc, Aluminum, Magnesium And Copper. In the USA, ZAMAC is commonly known as Pot Metal. Originally developed in Germany during the 1920s, ZAMAC met a demand for a material that could enable the production of intricate precision castings. For example, automotive engine carburetors were becoming very complex and cast iron, the popular carburetor material before ZAMAC, could not be cast into complex shapes with precision, so ZAMAC became the new material of choice. ZAMAC enabled toy trains to be cast with superb detail such as on the Lionel 400E Hudson.

The original alloys of ZAMAC were chemically unstable which caused the so called Zinc Pest of swelling and exfoliation of the parts made from it. Refinement of the ZAMAC alloy composition and processing of the alloy evolved throughout the 1930s and 1940s into the superior ZAMAC in use today. Unfortunately, some train manufacturers such as Dorfan and Lionel were victims of early ZAMAC.

The issue with current die cast ZAMAC toy trains in my opinion is explainable by discrepant alloy processing and or die casting. Start-up production in a plant lacking die casting experience with ZAMAC is also a likely culprit. These causal factors may explain why the Zinc Pest is not prevalent in the general market place, but it has occurred sporadically as in the toy train cases discussed on this forum. 

Pot luck with pot metal!

Please note that very few cast zinc items have been affected by, or ever will be affected

by, this issue, regardless of age, era, seller or country of manufacture. An item cannot

"catch it", and storage conditions cannot cause it, though I have read that storage

under cold (or was it hot?) humid conditions can speed up its appearance if the metal

is -already- contaminated. I'm not sure that I believe this, but I cannot say definitively that it is not true. It seems unlikely that a mere damp basement can cause a molecular

reaction in a cast, non-ferrous metal. But, I don't know.

Zinc casting is an old process and is used all over the world to make all sorts of things that live far more demanding lives than our model trains.

Sure, cast brass or cast bronze would be "better" (you can solder to it, for one thing!)

where casting is called for. Problem is, the cost is far greater than the cost of zinc/zamac,

and your models would weigh even more. That $2000 loco might well become a $4000

loco, half again as heavy, or some such.

Ditto for me, I will be contacting MTH to see what they can do...Thanks!

Jeff Davis

The problem seems to stem from quality control at the raw material source in most cases. The time period mentioned had zinc pest issues outside the model railroad industry, and also  appeared in other die-cast hobby areas. A scan of home machine-shop forums shows some discussions.

I understand that alloy selection, melt quality and temperature control, along with lead impurities are the main culprits. Once the model is made, the die is cast. ("Thinks" : So that's where that phrase came from...) I would hope the manufacturers would make some attempt at exorcising this ghost from the old days.

The tender shells for the torpedo is available under warranty from MTH. You have to contact them and get a return authorization for the shell, or what is left of it, send it to them and they should send you a replacement. This is a known problem, I have gotten several for customers. 

Harry Henning recently returned one of these for a new shell from MTH, they know about this issue.  It should be a free replacement.

Hello Everyone

 Thanks for all your info. I will contact MTH about the problem shells and let you know what happens.

Thanks again,

Thom Cholowski

Saskatoon,Saskatchewan

Canada

When I was in HO scale this was a real problem with old Varney, Penn Line and Mantua locos from the '40s and '50s. Old die cast zamac trucks used to be very susceptible. Has not bee an issue in the newer HO equipment from the mid '70s on, that I am aware of. Have heard of it happening in O and S gauge Flyer as well.

Zinc pest ultimately put Dorfan out of business. It's a shame, because they tried to replace every bad casting and went bankrupt in the attempt. Their trains were beautiful and they actually wanted people to take them apart, look at the way they worked and understand them--but lead contamination got to most of what they made.