Mazak 'rot' ... arrghhh!

[Jenny Emily]

Dinky Toys and Hornby Dublo used to suffer terribly from this. In particular, the Hornby Dublo items made prior to the second world war were especially prone. I have had in my possession a southern brake van that had had three of the four wheels crumble to dust. Strangely, the fourth wheel and the chassis were fine, showing that variation can exist simply between different batches.

 

Apparently this came to a head post second world war when Hornby Dublo discovered that items that had been in store through the war had crumbled in their boxes (I believe post 1940 they were unable to sell items, even those made and in the warehouse, because of restrictions in place). The problem was traced to poor quality control in the melting of the alloys and in some cases it was the binding wire from the sacks holding the raw ingots that were tossed into the mix, adding impurities. Once this issue was sorted, I haven't seen much evidence of further occurrences in Hornby Dublo's production run except for one through station that had a bloom appear on the surface, though even this didn't result in failure of the casting.

 

It stands to reason that a failure to adequately ensure a lack of contamination in the alloy mix and the mazak rot will turn back up just as it did in the 1930s. Perhaps workers in the factory in China are doing exactly what Binns road employees had done 80 years before, and tossed the binding wires from the sacks of alloy ingots into the melting pot.

[STRAT'71]

"Mazakgate" strikes again !!!!!

 

At least Hornby Customer Services do the decent think and attempt to repair of replace models or offer a voucher in lieu. Excellent service I think, considering some of these products are 10yrs old or more and well out of the guarantee period.  

When I recently queried this with Hornby concerning my Evening Star, I found them less than helpful.

[TheSignalEngineer]

Made since 1960, and before production moved to China, perhaps.

Regards

Trix Westerns were prone to chassis disintegration, but I never saw it on other Trix models. On Hornby Dublo I have stuff from post-war to the end of production and have not had any failures yet.

[TheSignalEngineer]

Can I just check something? You're suggesting that these parts are deliberately being manufactured to such a poor standard that it is inevitable that they will fail?

Why do you think that cars used to start falling apart after 3 years before coated steel was used for the panels?

[phil-b259]

The wikipedia article also states that "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."   So that's ok then as anything after 1960 wont need the sarsons... oh, wait...

 

Note the word usually in the article.

 

While it is true that as manufacturing standards have improved over the decades the chances of a model suffering 'zinc pest' have reduced, that does not mean its gone away completely. 

[APOLLO]

Trix Westerns were prone to chassis disintegration, but I never saw it on other Trix models. On Hornby Dublo I have stuff from post-war to the end of production and have not had any failures yet.

 

Just checked my blue Trix Western - all OK. Bought her around 1974, gave her a run to stretch her legs. Oh for all modern stuff to be so reliable after 40 years !!

 

Brit15

[BR60103]

There is a quote in one collecting book (it's in the library, and they're closed for the night) that, roughly, a pennyworth of lead will contaminate a ton of alloy.

 

Part of the problem may be re-use of crucibles (or whatever they are) for different alloys which can't be flushed effectively between batches.

[Fat Controller]

There is a quote in one collecting book (it's in the library, and they're closed for the night) that, roughly, a pennyworth of lead will contaminate a ton of alloy.

 

Part of the problem may be re-use of crucibles (or whatever they are) for different alloys which can't be flushed effectively between batches.

The lead is present in association with the zinc in the ore, I believe; Avonmouth Smelter used to separate the lead from the majority of the zinc it produced, leaving a residue which was effectively lead contaminated with zinc. This dross used, until the plant closed, to be sent by rail to a plant in the Netherlands. It could be that the Chinese haven't got the capability to separate the two as completely, or that they simply don't care. I don't think that the binding wires themselves would have contaminated the Binns Road Mazac, as the melting point of the steel would have been too high; it might have been the lead seal that had been put on the twisted wires to show if the contents had been tampered with, however.

[The Johnster]

A bit worrying.  I assume that this material is used to save costs, both on the raw materials side and that it is easier/cheaper to work or mould.  From reading the above and factoring in my almost complete lack of knowledge when it comes to matters chemical or metallurgical, quality control seems to be problem, and perhaps the Chinese are on the same learning curve as Hornby was in the late 30s.  I can see the point from the manufacturers side; an easily worked material which is heavy and improves the tractive effort but is cheaper than steel, doesn't rust, and doesn't affect the magnet in the motor.  Perfect, in fact, if the material and perhaps it's manufacturing process can be managed to a constant and adequate standard.

 

The way industry works in China is that a large company will often contract out processes such as this to smaller ones, and it may be that at the bottom end of the scale chassis blocks are being produced in village forges and agricultural workshops to be sent to a factory for assembly, a factory which will have dozens of sources of the product.  The people producing them will probably have no idea what they are for, or care for that matter.  It is particularly difficult in this scenario to implement a reliable quality control and some batches will be better than others.  The company here (Hornby, Bachmann, etc) is responsible for selling the item and that it is fit for purpose, but it is, to be fair to them, it's pretty much out of their hands except to change suppliers, which will likely all be prone to the same issues anyway.

 

Is there anything we can do?  Was pickling a joke, or does it help by dissolving impurities (for all I know it might)?  In the voice of Mrs Lovejoy from The Simpsons, won't somebody think of the children, or at least me in 5 years time with a crumbling loco fleet...

[Fat Controller]

A bit worrying.  I assume that this material is used to save costs, both on the raw materials side and that it is easier/cheaper to work or mould.  From reading the above and factoring in my almost complete lack of knowledge when it comes to matters chemical or metallurgical, quality control seems to be problem, and perhaps the Chinese are on the same learning curve as Hornby was in the late 30s.  I can see the point from the manufacturers side; an easily worked material which is heavy and improves the tractive effort but is cheaper than steel, doesn't rust, and doesn't affect the magnet in the motor.  Perfect, in fact, if the material and perhaps it's manufacturing process can be managed to a constant and adequate standard.

 

The way industry works in China is that a large company will often contract out processes such as this to smaller ones, and it may be that at the bottom end of the scale chassis blocks are being produced in village forges and agricultural workshops to be sent to a factory for assembly, a factory which will have dozens of sources of the product.  The people producing them will probably have no idea what they are for, or care for that matter.  It is particularly difficult in this scenario to implement a reliable quality control and some batches will be better than others.  The company here (Hornby, Bachmann, etc) is responsible for selling the item and that it is fit for purpose, but it is, to be fair to them, it's pretty much out of their hands except to change suppliers, which will likely all be prone to the same issues anyway.

 

Is there anything we can do?  Was pickling a joke, or does it help by dissolving impurities (for all I know it might)?  In the voice of Mrs Lovejoy from The Simpsons, won't somebody think of the children, or at least me in 5 years time with a crumbling loco fleet...

The way that the Chinese industry works is little different from manufacturing anywhere else. The manufacturer of a system, for example a boiler, will buy in components and sub-systems from myriad small suppliers, many of which will be little more than one-man bands. The difference is that quality control is probably much more rigidly applied here than in China.

As for pickling- don't!  Zinc is much more reactive than lead, so using dilute acid will only exacerbate the problem; my grandfather used to make his own flux, using a bar of zinc in a jar of hydrochloric acid. The reaction was quite interesting to watch, from some distance.

[34theletterbetweenB&D]

... I assume that this material is used to save costs, both on the raw materials side and that it is easier/cheaper to work or mould. ...

 Zinc alloys (Mazak, Zamak) in various formulations are used for small die castings for a whole 'basket' of properties. Doesn't erode the die material too fast, fills well and takes a good impression, easily machined, has sufficient weight, strength, stiffness, dimensional stability, corrosion resistance, readily accepts paints and platings, non-toxic; for a cost that results in a price acceptable to customers. It has a downside in its vulnerability to lead contamination. Show me an alloy that doesn't have any downside, and that'll be invulnar, principle components unobtainium, noncorrodium and fortisium, priced at the GDP of Switxerland per kilo!

[Mark Saunders]

Why do you think that cars used to start falling apart after 3 years before coated steel was used for the panels?

Was this not a cunning plan to have us all buying new cars at more regular intervals!

 

Remember when in the 1970's the first thing you did with a new car was have all the panels treated with wax oil to prevent corrosion!

 

Mark Saunders

[Horsetan]

.... in the 1970's the first thing you did with a new car was have all the panels treated with wax oil to prevent corrosion!

 

Ziebart

[bertiedog]

To clarify. no treatment works against the Zinc Rot, it is purely down to lead oxide occupy more space than pure lead in an "alloy" made of zinc which does not oxide as quickly as lead. Aluminium can cause the rot as well. which means the Chinese are using the alloy with addition metal in the melt. Hornby Mecanno had trouble with cigarette papers packs which where once lead or aluminium lined being thrown in the melt.

 

MAZAK (Also Zamak), is not just an alloy, it was a patented, copyrighted product that came from two Makers who knew about the purity issues from the 1930's or even earlier. It came as a product with a licence and lab standard purity certificates, and all designers know and knew this. It is melted in strict conditions and always in new crucibles, although waste can be remelted without problems.

 

If Rot occurs it is down to the maker of the Product, nobody else.

Conditions of storage do make a difference, warmth, damp etc will accelerate the oxides production.

When it occurs the maker must be told in no uncertain terms that it must be looked into, it is a major failure in the factory.

 

Stephen

[BrushVeteran]

 

Ziebart

Designed to seal in the moisture and make everything rot from the inside....................................dreadful stuff, steer well clear of it!    Duple and MCW used it on bus & coach 

bodies in the late seventies through the eighties and you ended up with lace curtains!  The quality of the steel may not have helped either.

 

Dinatrol is the stuff most people use now which is a penetrative wax based fluid which will stand the test of time.................but needs to be re-applied at periodic intervals.

 

Sorry for going OT but the word Ziebart is almost as bad as the big C word!

 

Unfortunately Mazak rot may not manifest itself for years and it is caused by impurities in the lead reacting within the zinc alloy usually causing expansion. I don't know how manufacturers can prepare themselves for something that is not apparent at the time of casting.................very difficult. Hornby were very good at dealing with the issues of some of the early class 31 releases but it has resulted in their abandoning the model for its 2016 release...............maybe because of unavailability of decent chassis blocks......I don't know. It certainly cost them!  Heljan similarly had a metallurgic chassis problem with the class 47, within a manufacturing batch and now there are no more spares because the model is presently not in production. Spares are only produced as an overrun on production so availability is limited to the quantity produced at the time.

 

We may have a problem with resin models in the future..............we maybe don't yet know but it is not unknown for chemicals to react with each other at a future time...........I have seen it with GRP where pockets of catalyst can attack a gel coat because of inadequate mixing. As has been said it is all down to quality control and these products should be laboratory batch tested but in China!!!!................I'll believe it when I see it!

[Hroth]

What I take away from reading this discussion is that we (as consumers) have no way to predict or prevent the rot in models that employ a "Mazak" like component for chassis, or superstructure, and that other materials may have analogous failure modes that could suddenly appear in the future, no matter how well the models are cared for.  One thinks of the nylon wheels/axels of certain split-chassis locos or the problems with splitting plastic cogs in motor transmissions.

 

Even manufacturers have little control over the actual quality of the product from factories half a world away that may well subcontract components to the cheapest local bidder.  The only way to avoid this is to take production back to the manufacturers direct control where absolute quality can be maintained.  This will cost, and that will be far more than most folk want to pay for a model locomotive.

 

Perhaps the only way to deal with it is to accept that our models MAY have a finite lifespan, enjoy them whilst they still function as expected and write them off when they fail.

[cheesysmith]

Look on the bright side, this rot in the new super detailed Hornby 31 has given me plenty of cheap all wheel drive, and detailed bogies/battery boxes for my Lima 31s.

[JSpencer]

Designed to seal in the moisture and make everything rot from the inside....................................dreadful stuff, steer well clear of it!    Duple and MCW used it on bus & coach 

bodies in the late seventies through the eighties and you ended up with lace curtains!  The quality of the steel may not have helped either.

 

Dinatrol is the stuff most people use now which is a penetrative wax based fluid which will stand the test of time.................but needs to be re-applied at periodic intervals.

 

Sorry for going OT but the word Ziebart is almost as bad as the big C word!

 

Unfortunately Mazak rot may not manifest itself for years and it is caused by impurities in the lead reacting within the zinc alloy usually causing expansion. I don't know how manufacturers can prepare themselves for something that is not apparent at the time of casting.................very difficult. Hornby were very good at dealing with the issues of some of the early class 31 releases but it has resulted in their abandoning the model for its 2016 release...............maybe because of unavailability of decent chassis blocks......I don't know. It certainly cost them!  Heljan similarly had a metallurgic chassis problem with the class 47, within a manufacturing batch and now there are no more spares because the model is presently not in production. Spares are only produced as an overrun on production so availability is limited to the quantity produced at the time.

 

We may have a problem with resin models in the future..............we maybe don't yet know but it is not unknown for chemicals to react with each other at a future time...........I have seen it with GRP where pockets of catalyst can attack a gel coat because of inadequate mixing. As has been said it is all down to quality control and these products should be laboratory batch tested but in China!!!!................I'll believe it when I see it!

 

They can stick production samples in a fridge for 6 months. The cold humid conditions are just right to accelerate the rotting process. Spray a thin layer of water once a day and you will soon see how impure mazak is. Even perfect mazak will turn white but with no expansion.

Edited December 23, 2016 by JSpencer

[gardenwall]

The lead is present in association with the zinc in the ore, I believe; Avonmouth Smelter used to separate the lead from the majority of the zinc it produced, leaving a residue which was effectively lead contaminated with zinc. This dross used, until the plant closed, to be sent by rail to a plant in the Netherlands. It could be that the Chinese haven't got the capability to separate the two as completely, or that they simply don't care. I don't think that the binding wires themselves would have contaminated the Binns Road Mazac, as the melting point of the steel would have been too high; it might have been the lead seal that had been put on the twisted wires to show if the contents had been tampered with, however.

It was the lead seals on the binding which caused the problem,  it was tempting to dispose of them in the melt rather that find a separate place.The binding was probably string rather than steel wire in those days and would burn off.

[dibber25]

I wonder how many of the products in which mazak castings are used, are expected to last indefinitely? I doubt that the Hornby-Dublo and Meccano items made 60 and more years ago were expected to last a lifetime. That they did so is just a spin-off benefit of the old 'Made in England' quality. Did anyone who bought in those days actually expect to be able to sell a mint, boxed example for tens of times what he paid for it? I suspect not. If all of them had lasted in mint condition, the value would be less now because there would still be lots of them. I wonder how long it is reasonable to expect our modern Chinese made models to last? A lifetime? We don't expect our TV, our vacuum cleaner or our fridge to last that long? I don't own a mobile phone but it seems no one expects their phone to last more than a year or two. I've a pretty big collection of ready-to-run locos and neither the time nor the desire to go de-boxing and checking them for corrosion at regular intervals. Doubtless I have one or two that will have been affected - I like T9s and Bulleid Pacifics so I've got several of each. If I was to find any with the mazak problem, I think I'd just throw them out. I can't see how I might justify going to Hornby and saying"I've had this in a cupboard for 20 years and it's falling to pieces. It's down to you to replace it." It's a tricky call, and one for which there's no simple answer. It stems from manufacturing in countries where things are cheaper and the reason they are cheaper is because there's less regulation, less care, less quality monitoring. (CJL)

[trevor7598]

Here is an extreme example of Mazak rot. The floor of this Corgi Q bus is about to pop out !.

We will all have to cross fingers that the Mazak, which is being increasingly used, in model

loco's to add weight does not break up in future years.

 

I have an extensive collection of model buses, and to be fair this is the only one affected. ( at the moment. )

[jjb1970]

Mazak rot has been around since before I was born, it is one of those problems that if it afflicts one of your models is dreadful but also one which needs a sense of perspective. Yes it happens, but it is mercifully rare (at least in my experience) and people shouldn't panic and assume all their models will disintegrate. I haven't found Chinese made models any more (or less) susceptible than British and European made models, it is common to point to China and blame shoddy Chinese quality and ignore the fact that the problem has afflicted models from all manufacturers using the material at some point.

[Legend]

I wonder how many of the products in which mazak castings are used, are expected to last indefinitely? I doubt that the Hornby-Dublo and Meccano items made 60 and more years ago were expected to last a lifetime. That they did so is just a spin-off benefit of the old 'Made in England' quality. Did anyone who bought in those days actually expect to be able to sell a mint, boxed example for tens of times what he paid for it? I suspect not. If all of them had lasted in mint condition, the value would be less now because there would still be lots of them. I wonder how long it is reasonable to expect our modern Chinese made models to last? A lifetime? We don't expect our TV, our vacuum cleaner or our fridge to last that long? I don't own a mobile phone but it seems no one expects their phone to last more than a year or two. I've a pretty big collection of ready-to-run locos and neither the time nor the desire to go de-boxing and checking them for corrosion at regular intervals. Doubtless I have one or two that will have been affected - I like T9s and Bulleid Pacifics so I've got several of each. If I was to find any with the mazak problem, I think I'd just throw them out. I can't see how I might justify going to Hornby and saying"I've had this in a cupboard for 20 years and it's falling to pieces. It's down to you to replace it." It's a tricky call, and one for which there's no simple answer. It stems from manufacturing in countries where things are cheaper and the reason they are cheaper is because there's less regulation, less care, less quality monitoring. (CJL)

Well today I was running my Hornby Railways 9F , a present from my parents for Christmas 1974 . Alongside her was Oliver Cromwell from 1975 and Mallard from 1979. All running perfectly well and as well as being nice locos , reminders of the people that gave them to me. So I do t think it's unreasonable to expect new models to last 20 years plus . Of course it's the sentimental value that makes them irreplaceable . We may have lower expectations for phones and washing machines, but of course when they expire we just replace them . Models are much more difficult to replace .

 

It is a function of Far East Manufacturing, but so what , do we need to accept it? It's cheaper to make them there but that shouldn't mean we sacrifice quality.

Edited December 22, 2016 by Legend

[rob D2]

Is the answer to ditch that material?

 

How about a stainless steel cnc cut chassis ?

I'd guess I'd need some overtime to afford a loco then though

[JSpencer]

Is the answer to ditch that material?

 

How about a stainless steel cnc cut chassis ?

I'd guess I'd need some overtime to afford a loco then though

 

You could try brass first.