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Possible chassis corrosion in Bachmann 47


pheaton
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  • RMweb Gold

Evening all,

 

Had some running issues in my Bachman 47522 so decided to investigate further although not related to the running problem the chassis appears to be suffering from the early stages of mazak rot or some form of oxidisation, with some surface cracking visible close up, at the moment the chassis is undistorted and not possible to break parts off but looks like the early stages of something big. See attached photos check your spoons folks!

 

post-1194-0-93337500-1535485578_thumb.jpg

 

post-1194-0-93203700-1535485604_thumb.jpg

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Great. When did the life expectancy of models become 10 years or less! Heljan 47’s, Hornby 31’s, then ive seens certain 50’s in danger, rebuilt merchant navy front bogies, and now bachmanns 47’s! Have you raised the issue with Bachmann?

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  • RMweb Gold

Not yet will do tomorrow looks like an issue affecting later models strangely the corrosion is in exactly the same place to check your models you don't need to dismantle check the for bodyside mounting screw holes the no2 end 2nd mans side will have a white deposit inside it

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  • RMweb Gold

In the first photo - the area in question does not appear to have any black paint applied. Is that from manufacture, or due to the corrosion?

 

Sure Bachmann will be happy to investigate the matter.

 

Regards,

 

C.

The inside of the chassis is unpainted, the first photo illustrates the white deposits on the inside of the chassis, ive got 6 affected models so far one less than a year old. Ive sent Bachmann an email offering to send the worst affected and the least affected model back so we will see what they say.

 

I will say though it doesn't fully match the "M/O" of classic mazak rot (i didnt see the white deposits on any of my 31s or 50s) and no chassis have failed despite some quite destructive testing on one of the blocks..... I do have some theories but ill let bachman comment first.

Edited by pheaton
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No need for panic yet. A little white powdery surface corrosion on unpainted mazak, especially sharp edges , is quite common and not necessarily a pointer toward risk of mazak rot. (As observed above, I have several Hornby Brush 2 mechanisms bought failed with mazak rot, not a trace of surface corrosion.)

 

Dimensional change is the key sign of mazak rot, if the casting has measurably expanded - easiest to assess over the longest dimension - then there is trouble. Any paint on the casting will quickly display crazing once expansion due to mazak rot is underway. If neither of these effects are seen, rest easy.

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Bachmann are aware of the issues raised by pheaton on RM Web last night regarding some of his Class 47 locomotives.

 

We have carried out several checks today on archive models and on spares held at Barwell. So far, no issues have been identified.

 

A similar operation is being carried out in China.

 

All alloy ingots supplied to our parent company have to conform to a set standard and each new supply is required to carry the necessary certification (Certificate of Conformance). We have used the same ingot supplier for over 10 years and this is the first time that any potential concern has been raised.

 

We will advise of our findings in due course both to the consumer who has contacted us directly and through this forum.

 

Dennis Lovett

Public Relations Manager

Bachmann Europe Plc

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  • RMweb Gold

So just for clarity i have contacted bachman, and had a similar response, to what andy has posted above, i must say its very refreshing to see a manufacturer respond like that in terms of how serious they are taking it..... After taking a long hard look it (with the aid of a metallurgist) would appear that the 47s i have listed (and I have in total 36) are suffering from something known as "wet stain" in laymans terms is a superficial corrosion where a zinc alloy has been exposed to moisture before its been able to form a protective oxidisation layer. However the 6 models affected are all stored with my other 47s and 37s and none of them are affected. I have offered to send them 47745 which is by far the most affected model. But if any of you guys have the white deposits they can be sanded off and resolved by painting the chassis.

Edited by pheaton
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is the patchiness in the same spot on all the 47s?  if so then I doubt its aything to worry about.   surely if the raw material was flawed signs of rot would spring up at random spots not the same same on every model of the same class?

 

maybe its just an inherent roughness born out on the tooling/cast mould for this model in that area which better explains the roughness in the same location on multiples of the same loco.

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  • RMweb Gold

The heaviest areas are all the same 2nd mans side screw hole and then spreading to the inside of the chassis. But if i look at hadrian 47404 which is getting on for 10 years old now there isnt a spot on it weird if anything.

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  • 2 weeks later...

I didn't hear anything back from. Bachmann so would assume they didn't find anything

 

 

Samples going back over 10 years on over 60 different model types (not just Class 47’s or diesels) have been checked at both Barwell and at our factory in China. We are delighted to say that we have found no evidence of zinc alloy rot and no examples of furring on anything that we have checked. The climate conditions in both locations are totally different.

 
 
Dennis Lovett
Public Relations Manager
Bachmann Europe Plc
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