Mazak 'rot' ... arrghhh!

[37403]

Having read this thread, I thought I'd have a look at some of the models I have in storage. My railfreight 56049 has a hairline slit above the chassis on the bodyside beside the drivers door. Would I be correct in saying this is the start of the rot?

Has anyone else had issues with the 56's?

[sb67]

Having read this thread, I thought I'd have a look at some of the models I have in storage. My railfreight 56049 has a hairline slit above the chassis on the bodyside beside the drivers door. Would I be correct in saying this is the start of the rot?

Has anyone else had issues with the 56's?

 

I have, R2646X, 56 049 in Railfreight grey. It has seized completely but I cant be sure it's Mazak related though as I cant see anything obvious.

Steve.

[37403]

Thanks for your response.

I would assume that Hornby will take responsibility for these matters?

[sandwich station]

Thanks for your response.

I would assume that Hornby will take responsibility for these matters?

They did but I don't think they do anymore.

Edited June 23, 2017 by sandwich station

[Fireline]

I have, R2646X, 56 049 in Railfreight grey. It has seized completely but I cant be sure it's Mazak related though as I cant see anything obvious.

Steve.

If it hasn't been run for a long time, the worms tend to "stick" in the top of the gear boxes. Take each top off, and try to spin the bearings. then strip them apart, clean them, light oil into the box, refit the worm, and a bit of light oil onto that, too. The same can happen to 50's and 60's.

[34theletterbetweenB&D]

Having read this thread, I thought I'd have a look at some of the models I have in storage. My railfreight 56049 has a hairline slit above the chassis on the bodyside beside the drivers door. Would I be correct in saying this is the start of the rot? ...

 

 No.

 

You need to get the mechanism out of the body to see any evidence. If the mechanism may be removed and replaced freely within the body shell once the securing screws are removed, then you can be confident that the mazak has not expanded, a key indicator of 'mazak rot'. The first evidence is often crazing of the paint as the expanding mazak stretches the paint until it cracks.

 

 

... R2646X, 56 049 in Railfreight grey. It has seized completely but I cant be sure it's Mazak related though as I cant see anything obvious.

 

 The design of mechanism Hornby use actually has some immunity to jamming due to mazak rot, as there are splined sliding sections in both drive shafts, so any expansion, (of which that in length is typically most significant) won't cause the drive shafts to disengage.

 

I say this with some confidence: I have three salvaged and very definitely mazak rot affected Brush type 2 (class 30/31) mechanisms all running extremely well, powering Airfix bodies. The bogie centres are probably a millimetre further apart than true scale, but unless you are Borg equipped with an optical gauge eye this is undetectable.

 

Exactly as 'Fireline' has already suggested, most likely one or both gear towers 'gummed up' with dried lubricant- only needs one to be gummed up.

[Talltim]

This guy has 3d printed a replacement chassis for his Bachmann QJ

http://atlasrescueforum.proboards.com/thread/5707/resurecting-americanizing-Bachmann-china-qj

[Forester]

  Zinc Pest (Mazak Rot); The Affected Models List

Now pinned in Modelling Questions, Help and Tips

[muir]

What frustrates me is that with my 1929-30 Lionel 390E - the frame is cracked but usable, the cylinder block okay, smokebox okay, wheels a little bit swollen but usable. This is, what, 87 years old?!?

My 1933-34 400E is good, wheels have been replaced, but all other castings excellent.

 

All my postwar dublo is excellent (of course).

 

I recently bought 11 (don't ask) NOS BTTB/Zeuke TT scale BR81's from the early 90's - 6 unusable because of badly swollen/cracked castings. 

 

It's just that everybody knows that mazak casting has to be exact. They figured this out before WWII.

 

It's a bit like "I'm going to fill up my petrol car with diesel. Oh, yes, of course I've read that it won't work well, but I'm going to give it a go anyway and maybe it'll run okay and get me home."

Edited September 23, 2017 by muir

[The Johnster]

We've sort of covered this; the problem is certainly quality control at it's roots, but it is exacerbated by the way things work in China, which is to all intents and purposes where all modern RTR originates.  An RTR firm will negotiate with a Chinese one, or even own an assembly facility or warehouse in China, which will supply the models, but does not actually manufacture any part of them; that is done by a plethora of smaller, and often rather 'lo fi' 'cottage industry' workshops dotted far and wide across that huge and diverse country, who are subcontracted and for all I know sub sub sub contracted to provide finished parts (we are discussing Mazak alloy chassis block here) to a CAD specification without necessarily knowing or caring what they actually are or are for.

 

Ensuring quality control over an allow produced in one factory crucible might be reasonably easy, even if batches vary a little in composition within allowances, but to impose it over what might be hundreds of workshops over a vast area is a different matter.  A faulty or below spec batch might be detected at the assembly stage, but equally might slip through as the only thing you can effectively quality control at that stage is the assembly itself!

 

I don't know what the answer to this conundrum is; hopefully the market's demand for more rigorous QC will sooner or later filter through to the root level of component manufacture.  Incidentally, I have had problems with British produced Mazak chassis from both Triang and Hornby Dublo, though this was many years ago; it is not a specifically Chinese problem...

Edited September 23, 2017 by The Johnster

[sandwich station]

 Incidentally, I have had problems with British produced Mazak chassis from both Triang and Hornby Dublo, though this was many years ago;

 

But not to the extent that it's showing up on China produced models now.

[The Johnster]

Modern Mazak problems may also be related to shelf time, like lube solidification.  One often hears of 'brand new never taken out of the box' models which have either had a long shelf life, or been bought against the day the layout is built and not used for some time while it is being built, giving trouble.  May be better to buy stuff and letit  out of the box a bit, perhaps on a display shelf where it can breathe, rather than storing it in the packing.  Presumably the packing is designed to hold the model safely for transit and some time after, but I doubt that anyone has done any work on how long after!  Of course, this in itself can lead to trouble with livery fading, damned if you do and damned if you don't!

 

The old Triang and HD models came in stout cardboard boxes in which they were held by cardboard formers (and how wonderful it was when you had something that shape and weight wrapped in xmas paper!) with little cardboard napkin rings to protect the couplers.  There was plenty of air to circulate around the model in there; modern packaging relies on plastic inserts closer to the body of the model and much less circulation of air takes place (though it is a very effective way of simultaneously packing and displaying the model on a shop shelf).  This may have some bearing on matters, though I mean it only as a suggestion and cannot quantify the state of affairs in any objective way.

Edited September 24, 2017 by The Johnster

[locomad]

 

The old Triang and HD models came in stout cardboard boxes in which they were held by cardboard formers (and how wonderful it was when you had something that shape and weight wrapped in xmas paper!) with little cardboard napkin rings to protect the couplers.  There was plenty of air to circulate around the model in there; modern packaging relies on plastic inserts closer to the body of the model and much less circulation of air takes place (though it is a very effective way of simultaneously packing and displaying the model on a shop shelf).  This may have some bearing on matters, though I mean it only as a suggestion and cannot quantify the state of affairs in any objective way.

Modern packing has some more disadvantages, it can take as much as 3 times the space, take 3 times of long to pack, and more likely damage the model in the process.

 

I can get 54 HD wagons in a box 4"x11"x16" that's about 0.4 cu ft, with modern stock I'am luckily to get even 20 wagons in, it doesn't matter so much if you have the space, or even a modest collection, but some of us over a lifetime can collect quite a bit.

 

I've noticed with some HD boxes a kind of coupling former built into the flap on the ends this no need for the round cardboard thing to protect the coupling, very convenient as you don't end up with loads of done cardboard bits on the floor.

 

Now I presume nearly all HD chassis is mazak I've noticed no rot on some items at least 70 years ago, some I can tell due to rust on wheels have been subjected to damp etc.

 

I've also know from the foster book how meccano discovered mazak rot on early products and lenghts gone to prevent later products from suffering clear case of lax quality controls

[adb968008]

updated list of affected models here (101 thus far)

http://www.rmweb.co.uk/community/index.php?/topic/123769-zinc-pest-mazak-rot-the-affected-models-list/?p=2865037

 

Personal thoughts on storage... styrene is an insulator, cellphone traps heat. Having a model in a box that sweats your loco in summer, and releases moisture in winter doesn't sound like an optimum solution. If it's stored in a variable temperature location, I'd imagine out side this style of packaging would make more sense. Bubble wrap i'd avoid to.

But ultimately.. if the alloy is tainted..all your doing is delaying the pain not preventing it.

Edited September 24, 2017 by adb968008

[The Johnster]

Another solution would be to stop using Mazak.  I cannot imagine that the material cost of the chassis block is a major part of the overall cost of the model, surely that is assembly of a number of disparate parts, and all that is required of the chassis block material is that it is reasonably rigid and heavy, and rustproof (or at least rust resistant).  Now, I am neither a qualified metallurgist nor do I have any sort of knowledge of production engineering, but would not a different material, perhaps whitemetal, be just as good or better?  What other applications are there for Mazak besides model railway chassis and what makes it so special in that role?

 

It is obviously highly satisfactory in the majority of cases, but needs very strict QC at the source, the small foundries and backroom workshops where it is mixed and poured into the moulds, and this cannot easily be provided under the present circumstances, so another material might be worth considering.

 

I'm lucky, and have not lost any models to this for many years, touch wood!

[adb968008]

Another solution would be to stop using Mazak.  I cannot imagine that the material cost of the chassis block is a major part of the overall cost of the model, surely that is assembly of a number of disparate parts, and all that is required of the chassis block material is that it is reasonably rigid and heavy, and rustproof (or at least rust resistant).  Now, I am neither a qualified metallurgist nor do I have any sort of knowledge of production engineering, but would not a different material, perhaps whitemetal, be just as good or better?  What other applications are there for Mazak besides model railway chassis and what makes it so special in that role?

 

It is obviously highly satisfactory in the majority of cases, but needs very strict QC at the source, the small foundries and backroom workshops where it is mixed and poured into the moulds, and this cannot easily be provided under the present circumstances, so another material might be worth considering.

 

I'm lucky, and have not lost any models to this for many years, touch wood!

 

In the older days the chassis used to contain lead, but that probably explains why Railway modellers are more extreme and of odd temperament with later age.

 

maybe use Brass.. but it aint cheap.

[APOLLO]

Coming soon - arrghhh MARK TWO !!!!!!!!!!!!!!!

 

http://www.independent.co.uk/environment/plastic-degrading-fungus-pakistan-rubbish-dump-islamabad-dr-sehroon-khan-a7962046.html

 

Brit15

[stewartingram]

We've had many many posts on Mazak rot. I'm no mettalurgist either, but I can read (though a lot of the posts do seem to be in invisible ink......)

The problem of mazak is not how it is stored, used, exposed to damp,sunlight,fairies etc. It is in the composition. What is chucked into the melting pot, and the quanties of whatever goes into it (I have absolutely no idea on this, but understand the principle) affect the final composition. Depending on the imperfections, the "rot" may set in earlier or later. You can't stop it, it is not like rust.

 

Stewart

[jjb1970]

Mazak is cheap and has pretty much ideal qualities for model use, especially being pretty easy to work. The mazak rot issue is unfortunate and shouldn't happen but the overall balance of benefit and risk is still pretty well stacked in favour of retaining mazak. Some companies talk about using tungsten but seem to revert to mazak, brass is great but brass models are pricey (although classic US outline brass is increasingly competitive with pastic RTR, albeit you're comparing old s/h with new).

Weirdly, some of the Korean brass manufacturers, including Ajin, ended up at risk of the Mazak rot pest by using the material for the gearboxes that were fitted to each axle.

[sandwich station]

Some companies talk about using tungsten

 

I would have thought tungsten would be impractical for models due to it's high melting point.

 

 

[jjb1970]

I would have thought tungsten would be impractical for models due to it's high melting point.

 

 

Indeed, I suspect the reason why we don't really see it is that as soon as manufacturers provide a cost for using it instead of mazak the idea is dropped.

[locomad]

There's nothing new about mazak rot, what worries us to some extent is it's used in a lot of other products as well and the quality seem to get worse the more recent the product was made.

 

While we might moan about our beloved and expensive model train falling to bits just a few years old it's highly unlikely to cause us any harm other than the stress of a refund.

 

I'am beginning to find other products which have failed due to mazak rot, electric iron, gas boiler parts, car brake hydraulic junction boxes, light fitting, all of which have a serious safety aspect

[Andrew F]

I gave the pound shop mountaineering shackles a wide berth.

[GordonC]

There's nothing new about mazak rot, what worries us to some extent is it's used in a lot of other products as well and the quality seem to get worse the more recent the product was made.

 

While we might moan about our beloved and expensive model train falling to bits just a few years old it's highly unlikely to cause us any harm other than the stress of a refund.

 

I'am beginning to find other products which have failed due to mazak rot, electric iron, gas boiler parts, car brake hydraulic junction boxes, light fitting, all of which have a serious safety aspect

 

.... but refunds are only issued for a limited time. Hornby has stopped refunding on Class 31s now, admittedly a long time after release, but I dont spend £100+ on models expecting them to crumble to worthless junk due to manufacturing faults. It'll be terminal for my involvement with a manufacturer if that happens to my models

[Fireline]

There's nothing new about mazak rot, what worries us to some extent is it's used in a lot of other products as well and the quality seem to get worse the more recent the product was made.

 

While we might moan about our beloved and expensive model train falling to bits just a few years old it's highly unlikely to cause us any harm other than the stress of a refund.

 

I'am beginning to find other products which have failed due to mazak rot, electric iron, gas boiler parts, car brake hydraulic junction boxes, light fitting, all of which have a serious safety aspect

 

It would be interesting to see the attitude of the companies that made those products, then compare it with Hornby's. I suspect that most of them will just rely on the age of the product, and do nothing about it at all. Hornby rebuilt the locos until they ran out of chassis, then issued refunds. Finally, they drew a line in the sand. 

 

Can I suggest that, as seems to be the case with most recent class 31 discoveries, if you have bought engines and stored them away, that you check them periodically? I don't mean once a week or similar, but often enough that it doesn't take 14 years from release for the fault to be found. That way, you can shout at H, or B, or whoever, that much earlier, and hopefully avoid being left out.