Mazak

Hi Nigel.  The models in question are " 21st Century Models". And still under Hornby guarantee, and sold in the U K.If these models were more than 5 years old, let  alone 10 or 20 years old I would not be worried.
Best wishes. Kevin

Hi KEvin,

I wouldn't worry about something that hasn't happened yet. Do an internet search every 6 months or so to see if there have been any reports of chassis problems. Most of my locomotive stock is 10+ years old, I never give it a thought. If you are tempted into buying an older model, check the various sites. Especially if it's a model where problems have been reported. Avoid those.

Nigel

BCDR wrote:

Hi KEvin,

I wouldn't worry about something that hasn't happened yet. Do an internet search every 6 months or so to see if there have been any reports of chassis problems. Most of my locomotive stock is 10+ years old, I never give it a thought. If you are tempted into buying an older model, check the various sites. Especially if it's a model where problems have been reported. Avoid those.

Nigel

Hi Nigel. Thank you for your reply. Your Locomotive Stock are they Hornby ? And do you have any/ many Class 31 in your MPD? Because as SRMan Jeff reported "the Mazak rot problem only applies to a few particular releases". Therefore unless you have these "few" in your stable you would not experience the problem.  Kevin 

Hi Kevin,

Yes. No. No. And no horses either. If you are concerned about that particular model get the shell off and start looking at the chassis, especially around the boogie gear mounting where there is the least metal. Efflorescence in the form of light grey powder on exposed alloy, crumbling or paint bubbling will be indicative of the "pest". If the ends break off under light lateral pressure you definitely have it. MAZAC is tough, drop the chassis on the floor and it will not break (coupler mounts excepted), although not a recommended test for the "pest".

Nigel
Edit: This is not just a Hornby class 31 issue. My two examples were from other manufacturers. If you are still in warranty I wouldn't worry, out of warranty I would test the chassis (including scraping the paint) every 4-6 months when you service the locomotive.

I know that this is an old topic but Mazak Rot (Inter Crystaline Corrosion) seems not to be confined to the classes already referred to - I had a Class 31 that had a rotten chassis and the T9 problem was common knowledge.  [Technical explanation provided by BCDR and others earlier on this thread]

Today, during a running session at my local club, I pulled a Thompson L1 from it's box to test a replacement rear bogie that had suffered from the Rot and which I had replaced last week.  To my dismay, whilst the new bogie ran well, the front pony truck wasn't looking good and on examination, it too has the Rot and so another eBay purchase has been made  

Worse still, I read on the RMWeb or a Hornby Forum (I can't remember which) that the J15's may be subject to this as well!!!   I love these little engines.

There does not appear to be a time-link between these issues i.e. these are not models released around the same time.  The problem is one of general material fault that sounds like it was around in Hornby Dublo days and still persists today.  Its also something that seems quite difficult to detect at the inspection stage.

As it happens, the Hornby Thompson L1 has a reputation for having a wonky front pony truck that is located by 2 laterally positioned guides rather than a central pivot.  As a result, the truck has a tendency to slew sideways when the loco is running forwards.  Strangely, not all models seem to do this and there are several reviews (and reviewers) out there who have reported that their engines run perfectly!!

I am hoping that the replacement truck improves my L1 although as I plan to run it bunker first anyway, its not a major pain.

Perhaps a list of Mazak Rot affected classes would be useful to potential buyers - or does the random incidence of the problem make that somewhat impractical?

Barry

Barry,

 There is a list here, regularly updated:

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

the latest version (31/3/20) is attached to first post of the Topic.
 Shows models and dates, compiled from members reports.


The list has grown by a further whole page from last time I looked in 2019

   
Colin

It used to be called "built-in obsolescence" ………………….

I suppose mazac must be the cheapest material for the job so, given that models are already becoming "elitist" in terms of prices, using a more suitable material would just tip the balance over.

I pity those collectors who just want to keep their pristine models in boxes for posterity ………….what with mazac rot, split axles and dried out nylon bearings, they'll end up with a box of crumbs in a few years time !

Thanks Colin

I note that the L1 is present but only as a result of rear bogie problems so I wonder of my front truck is just an emerging issue?  Its on the list anyway.

Thankfully, not any of my other locos appear so I think I will be OK but will keep a wary eye on it during the routine maintenance.

Barry

Nothing to do with material cost. Iron or steel would give more room in a chassis (due to the  difference in density) but with a more expensive casting process. 

Nigel

Hi Colin.    Please excuse my ignorance on the subject of Mazak Rot, is this a problem exclusive to hornby?And if everyone, except me, are fully aware of the problem then how is it they are still in business?
Best wishes Kevin

No Kevin, Hornby is not the only firm that has that problem

Zinc Pest (Mazak Rot); The Affected Models List - Modelling Questions, Help and Tips - RMweb

The "pest" has been a known problem for years in the zinc alloy industry. Good quality at the manufacturing end and good quality assurance is required. If not bad batches appear. Problem s it usually takes a few years to appear. By which time the model is a) usually discontinued, and b) guarantees have lapsed. 

Nigel

Hi Ron.  Thank you for your reply. Maybe it is a Chinese problem as it is occurring with other manufacturers as well?Best wishes Kevin 

Hi Kevin,

The pest occurs when the zinc is contaminated. Given that almost all model are made in China then that is where the problems are. If the company contracting the manufacturing (Bachmann, Hornby et al) ensured quality control was done properly (QC) and audited it (QA) there wouldn't be a problem. Pure zinc is expensive, cheap zinc is…cheap. There is a long supply chain, so lots of vigilance required to make sure somebody does not slip in a cheap ingot or three into the alloy mix.

I believe a chassis should be guaranteed for at least 10 years given that it is not subject to any meaningful stress. On


Nigel

Hi Nigel.  Thank you for your reply.  I had a suspicion that could have been the case. Best wishes Kevin