BR Std 4 - Latest Version

[Right Away]

Some years ago I had a BR Standard Class 4 4-6-0 No 75071 (R3016A) whose drive mechanism failed. A used version purchased sometime later also gave trouble. 

That two such delightful looking models (which are now on the "Mazak Rot List") to fail was very disappointing.

 

Would it be safe to assume, Hornby, by now, will have addressed the Mazak issue in their latest version of the BR4 (R3548)?

[brushman47544]

Unfortunately Hornby doesn’t have any control over Mazak rot. The factory making a particular model doesn’t use contaminated Mazak deliberately and will not know if the model will be affected until the rot appears some time later. Hornby may be able to insist on high checking levels prior to use but this is no guarantee. Hopefully new models will not rot but unless they do you don’t know.

[The Johnster]

This is a perennial issue and given the Chinese production model, which involves sub sub sub sub contracting out to what are basically cottage industry foundries to have the chassis blocks cast and then transporting them to the assembly facility, I am surprised (and pleased) it doesn't happen more often.  Mazak is actually not a very good material to make a chassis block out of, though it's better than the old Lima plastic chassis.  Any ferrous metal is prone to rusting, and brass is expensive, both as a material and because it is difficult to work, meaning that shaping and drilling it is expensive as well.  

 

There may be less of an issue with the new model if the chassis blocks come from different suppliers, but Mazak rot takes some time to appear and if there is an issue Hornby will not be aware of it yet.  The problem is compounded by lack of spares, and there are probably no spare chassis blocks.  This is because exact production run numbers of components are ordered and delivered for assembly in the facility in China, and even if there are spares in China they do not make it over here.  It is not economically viable for Hornby or anyone else to hold stocks of or to have distribution networks for spares, as the 'just in time' production principle is employed for maximum efficiency, something which can be done quite effectively in the digital age.

[34theletterbetweenB&D]

A hand held XRD will do for a quick and non-destructive goods inward check on castings. If there is any lead in the Mazak, condemn the lot. Hopefully someone at Hornby is aware and has implemented this: pretty confident that Kader do based on some of their information about ten years past...

[The Johnster]

I'm very lucky in that I've never had the problem in 60 years of being involved with RTR model railways, but feel for those who have.  A problem for the manufacturer/commissioner is that they are not aware of the problem until some time after the model has been built, and usually years after the warranty has expired.  The ultimate answer is to not use Mazak, but I've pointed out the deficiencies of other materials.  'Healthy' Mazak is cheap, easy to work, meets distribution underwriting requirements, and does the job, and quality control in the Chinese model where actual suppliers are many, varied, and constantly changing, is amazingly good considering...

 

A replacement material for chassis blocks needs to fulfil a number requirements.  It must be cheap, easy to cast, easy to work, meet safety regs in terms of lead and other unpleasantries, be non ferrous to avoid rust, heavy, resistant to expansion and contraction, take paint, and probably a load of other things I haven't considered.  Unobtainium is ideal... 

[JSpencer]

17 minutes ago, The Johnster said:

I'm very lucky in that I've never had the problem in 60 years of being involved with RTR model railways, but feel for those who have.  A problem for the manufacturer/commissioner is that they are not aware of the problem until some time after the model has been built, and usually years after the warranty has expired.  The ultimate answer is to not use Mazak, but I've pointed out the deficiencies of other materials.  'Healthy' Mazak is cheap, easy to work, meets distribution underwriting requirements, and does the job, and quality control in the Chinese model where actual suppliers are many, varied, and constantly changing, is amazingly good considering...

 

A replacement material for chassis blocks needs to fulfil a number requirements.  It must be cheap, easy to cast, easy to work, meet safety regs in terms of lead and other unpleasantries, be non ferrous to avoid rust, heavy, resistant to expansion and contraction, take paint, and probably a load of other things I haven't considered.  Unobtainium is ideal... 

 

Accurascale will be using tungsten in their chassis blocks. While more expensive, I guess the overall increase in cost on a 300+ part model that is assembled and painted by hand is probably negligible for the benefits it gives in completely avoiding this pest and also allowing a decent amount of internal detail /DCC fitments while still increasing the loco's actual weight and thus haulage power.