Exploding chassis

[Adrian]

I am sure many colleagues on this forum, in addition to me, "dip" into other scales one way or another.

Back in August 2011 RMweb saw the beginning of a long running thread concerning the problem of disintegrating chassis on the Hornby class 31.  This thread continues right up to the present day with several folk encountering the problem in their cherished models.

I understand the problem has been the material (mazak?) used in chassis block construction.  Maybe a metallurgist on the forum could give some informed insight here.

Anyway, my reason for making this posting (as a fairly new member of the N gauge community) is to ask whether any such major issues have occurred amongst models in this scale.

Regards

Adrian

PS I seem to recall that Heljan had some "materials problem" some time back, but I don't have the details immediately to hand

[railsquid]

I think I even posted on that thread. I'm a bit of a n00b to N-gauge but I've been reading this and other forums extensively and have yet to hear any tales of Mazak or exploding chassis. The main enemy here (primarily for Graham Farish stuff) is the dreaded split gear.

[Newportnobby]

My dear old Farish class 31 was one of the first locos I bought Lord knows how many years ago and it has always been a lovely runner but I got it out of its box this week to find a gear has split. It's probably nowhere near as accurate as the new model due imminently but it's lasted me many a year.

[Busybee]

The new 31s have landed, in the post, on its way to me..............

[Dr Al]

I understand the problem has been the material (mazak?) used in chassis block construction.  Maybe a metallurgist on the forum could give some informed insight here.

Anyway, my reason for making this posting (as a fairly new member of the N gauge community) is to ask whether any such major issues have occurred amongst models in this scale.

Mazak rot hasn't afflicted any Farish or Dapol models to date (and hopefully never will).

The occasional the Peco Jubilee can suffer from bulging tender drive (on a minor scale though, usually fixable). Some fairly ancient Rivarossi motors can suffer from something similar in the motor magnets which seizes up the whole motor to a write off. I believe some early Atlas models can suffer from crumbling chassis blocks.

On the whole it's not something that's afflicted N gauge models and long may that continue!

Split gears on the other hand are common, but fortunately far easier to put right, and unlikely to write off a model in the way so many Hornby 31s (and others I believe) have been.

Cheers,
Alan

[Dorsetmike]

I've had Jubilee and Nord Pacific tenders from Rivarossi crumble, usually round the axle slots.

[DELETED]

I understand the problem has been the material (mazak?) used in chassis block construction.  Maybe a metallurgist on the forum could give some informed insight here.

Only to say mazak is generally an alloy of magnesium, aluminium, zinc and copper (known also by a few other different names).  It's a step-up from the likes of whitemetal.  I don't know the specifics other than reading forum threads and perhaps the odd mag article.  I only read it was supposedly a batch (or few batches!) of a particular combination of the constituent parts.  Hopefully nobody else used that particular mix, I've not heard it yet for GF / Dapol anyway but I have only been in n gauge for 5 years or so.

...Did I read somewhere there were also problems with it reacting with some form of paint or PVA type glue also?

[Ozymandias]

Old Atlas chassis definitely crumble! I don't know what metal they're made from, but with age they start splitting and disintegrating. Two part metal glue has helped me rescue a couple - for how long I don't know!

[DesertHound]

Hi Adrian

Very interesting topic you bring up here.

My experience with Poole (UK) production Graham Farish is that there's nothing on an epidemic scale. Some identical chassis to me seem better than others and "appear" to have distorted over time. This is evidenced by the difficulty of achieving perfect shaft alignment through the bearings. I ponder the following;

a) they were just "bad" batches
b) they were "good" batches, but of an inferior compound
c) they've been somehow exposed to the elements that possibly distorted them in some way.

As I say, in my opinion nothing epidemic, but some chassis are definitely better than others (possibly due to distortion). Nothing has exploded on me (yet!)

Just my observations and experience.

Cheers

Dan

[Dr Al]

Two part metal glue has helped me rescue a couple - for how long I don't know!

I suspect there you've won the battle for now, but may ultimately lose the war as presumably it's still crumbling within  . But if it keeps it going for another 5 or 10 years then all's good!

Cheers,
Alan

[DesertHound]

Two part metal glue has helped me rescue a couple - for how long I don't know!

I suspect there you've won the battle for now, but may ultimately lose the war as presumably it's still crumbling within  . But if it keeps it going for another 5 or 10 years then all's good!

Cheers,
Alan

How old are these crumbling Atlas chassis, just to out things into some kind of context? Yes, won the battle, but perhaps not the war. Visions if sticking your finger in a dam come to mind 

[elmo]

My first farish date from 1980 - 50+locos, steam and diesel - no problems regarding metal 'failure' to report.
As an aside - was using a 1981 class 47 last night, even the bulbs are original, all still fine.

Elmo

[Mr Sprue]

I am sure many colleagues on this forum, in addition to me, "dip" into other scales one way or another.

Back in August 2011 RMweb saw the beginning of a long running thread concerning the problem of disintegrating chassis on the Hornby class 31.  This thread continues right up to the present day with several folk encountering the problem in their cherished models.

I understand the problem has been the material (mazak?) used in chassis block construction.  Maybe a metallurgist on the forum could give some informed insight here.

Anyway, my reason for making this posting (as a fairly new member of the N gauge community) is to ask whether any such major issues have occurred amongst models in this scale.

Regards

Adrian

PS I seem to recall that Heljan had some "materials problem" some time back, but I don't have the details immediately to hand

Hi Adrain just to set matters straight "Mazak" is a brand name for "Zamak" which is a zink alloy comprising of elements of aluminium, magnesium, and copper. I would be very surprised to discover that this metal combusted under heat as I actually smelt the stuff!

Therefore I would be more inclined to think that maybe the chassis was made from Magnesium Alloy.

Regards
Mr Sprue

[RussellH]

Some poor chap handed his heljan drs 47 into the shop for repair - the chassis had swollen and cracked the end of the body. Normal route for this is a replacement chassis from Heljan but howes (the uk dealers) are nil stock. So it was shortened and the body repaired - best to avoid buying any of these!

BUT it was nowhere near as bad as this chap on rmweb...

http://www.rmweb.co.uk/community/index.php?/topic/73731-heljan-47-chassis-expansion-can-anyone-beat-my-model/

At least this is one thing we dont seem to suffer from as yet.

Russ

[EtchedPixels]

Not seen the contaminated mazak in N thankfully

There are some weird ones though - some Dapol 14xx and M7 locos the handrails expand over time and have to be replaced. Not sure what plastic they used but it's not a fitting problem or stretching - the parts genuinely grow bigger !