Mazak 'rot' ... arrghhh!

[JSpencer]

The easiest way to avoid mazak rot is to use the item. Electricity has a habit of reduce the rate at which metals rot, simply because it replaces instantly lost electrons due to the rotting process.

[Hroth]

The easiest way to avoid mazak rot is to use the item. Electricity has a habit of reduce the rate at which metals rot, simply because it replaces instantly lost electrons due to the rotting process.

I doubt it.  I don't think any modern loco uses the chassis as part of the conductive circuit!

 

Also, on our narrowboat, we have a thing called a Sacrificial Anode, a whacking big lump of zinc, bolted to the steel hull, adjacent to the propellor. This erodes away in preference to the prop as it makes a better electrochemical battery with the steel hull. (something like that anyway, I'm hazy on the details...)  A current passing through impure mazak might just accelerate the process.

[34theletterbetweenB&D]

There's only one way to slow mazak rot, and that's to keep it warm and dry. The failure mode is that the lead promotes a change in the crystalline structure of the solid. I don't remember the temperature break point - it is ine the 'ambient' zone -  but below this temperature a slightly bulkier crystalline structure is more stable, and that's the cause of the swelling. With no lead present, the low temperature risk is very much reduced, but it may still happen in the longer term. Mazak is a 'young' alloy formulation; unlike brasses. bronzes, pewters, steels where we centuries or even millennia of experience, we probably haven't yet seen all the tricks it has in store.

 

Is the answer to ditch that material?...
 

 As I think you are aware, the alternatives are likely to be more expensive, one way or another. Mind you, find an equivalently capable alloy (see post 37 for some of the properties to be matched or beaten) with less downside and equal or better economy and there's money to be made.

[jjb1970]

Manufacturers often talk about replacements for mazak but generally retain mazak, probably when they do the sums and analyse market reaction to pricing models with the more commonly talked about alternatives I'm guessing.

[cheesysmith]

   How about replacing the mazac with depleated uranium? Even denser, so increasing haulage, and could use the glow in the dark properties for lighting effects?    

[Betty's Husband]

Better still, don't deplete it and keep the U235 and it will form the basis for the next generation of live steam models. Just add water....

[brigo]

Perhaps there is an opportunity for someone to make replacement chassis blocks and parts using CNC machining. This is certainly the case with the Austrian manufacturer Klein Modellbahn whose products often suffered with the zinc problem. While they were in business they were quite happy to send out replacement parts but after they ceased trading other businesses have been making replacement CNC parts in aluminium or brass.

 

Brian

[34theletterbetweenB&D]

Drifting off topic somewhat, but whenever one of the Bachmann 9F's goes past on the layout, the thought crosses my mind that a replacement chassis block accurately showing the frames down to the diaphragm plates would 'ice the cake' on this model. A tungsten alloy core with applique etched frame sides perhaps, for no weight loss with better appearance perhaps?

[Forester]

I frequently unpack new electronic and other household items with dehumidifying crystal sachets in the box. I toss these sachets into the back of the display cabinets where I store most of my locos and have never yet had a case of mazak rot, despite having some of the noted sufferers.

 

Keep them as warm and dry as possible. 34C has it exactly right.

[JSpencer]

I doubt it.  I don't think any modern loco uses the chassis as part of the conductive circuit!

 

Also, on our narrowboat, we have a thing called a Sacrificial Anode, a whacking big lump of zinc, bolted to the steel hull, adjacent to the propellor. This erodes away in preference to the prop as it makes a better electrochemical battery with the steel hull. (something like that anyway, I'm hazy on the details...)  A current passing through impure mazak might just accelerate the process.

In the case of your boat, the parts are not connected to the electrical circuit. If they were connected to the electricity generator, the zinc will rot slower. On the other hard, it you using the zinc block to act as battery, it will rot faster.

 

Agree the chassis block needs to be part of the electrical circuit in order to work. My Trix lasted through 3 decades of constant use and never showed any signs of the zinc pest. I stopped using them for 5 years and the collection is going home rapidly.

[toboldlygo]

Drifting off topic somewhat, but whenever one of the Bachmann 9F's goes past on the layout, the thought crosses my mind that a replacement chassis block accurately showing the frames down to the diaphragm plates would 'ice the cake' on this model. A tungsten alloy core with applique etched frame sides perhaps, for no weight loss with better appearance perhaps?

 

And if it ever falls from the layout, you could end up with a hole in the floor - having seen what a tungsten riveting dolly can do to a reinforced concrete floor first hand   

Edited December 23, 2016 by toboldlygo

[adb968008]

You could try brass first.

Peters spares have done exactly that, for example the brass motor housings for the T9, it's saved two of mine recently as they make brass alternatives.

[jjb1970]

Ajin precision of Korea managed to snatch defeat from the jaws of victory by using mazak for their gear boxes. For those not familiar with Ajin they supplied brass models made to an exceptional standard to many of the worlds great brass model companies (including Overland). The models were all brass however one of their trademark ideas was that a drive shaft powered a small gear box for each axle, looking from the underside it almost looked like the axles had traction motors and it allowed Ajin to avoid the large block effect that lets many bogies down if looked at in side profile. Great idea in theory but by using mazak for these gear boxes it introduced the potential for mazak rot into an otherwise all brass model.

[Chameleon]

Some manufacturers handle the problem better than others. A friend had a Brawa class 232 diesel the Mazak frames in the bogies were banana shaped! He fired off an email enquiring if they knew about the problem and about a week later a new set of bogie frames and some other parts duly arrived. Excellent customer service!

[Fat Controller]

I frequently unpack new electronic and other household items with dehumidifying crystal sachets in the box. I toss these sachets into the back of the display cabinets where I store most of my locos and have never yet had a case of mazak rot, despite having some of the noted sufferers.

 

Keep them as warm and dry as possible. 34C has it exactly right.

34 Degrees- you must live in the same sheltered housing as my mother-in-law.

[jjb1970]

Some manufacturers handle the problem better than others. A friend had a Brawa class 232 diesel the Mazak frames in the bogies were banana shaped! He fired off an email enquiring if they knew about the problem and about a week later a new set of bogie frames and some other parts duly arrived. Excellent customer service!

 

In fairness to Hornby, they've tended to be very good in terms of compensating owners who have been affected. Based on what I've seen of the experiences of friends and associates they seem to have had a much better policy than other UK suppliers in this particular area.

[34theletterbetweenB&D]

34 Degrees- you must live in the same sheltered housing as my mother-in-law.

 "Why are you wearing shorts, it's winter?"

"Outside perhaps, in here it's the eternal summer of the spotless mind."

And if it ever falls from the layout, you could end up with a hole in the floor - having seen what a tungsten riveting dolly can do to a reinforced concrete floor first hand 

 Impressive stuff when you get a lump of it. However we're only talking a 100g or thereabouts in the chassis assembly for the purposes of the model; same weight as the mazak would supply but in far less volume enabling the frame space down to the diaphragm plates to be represented.

 

FWIW, past experience of making 4mm models very heavy with lead for outdoor operation to secure reliable pick up and traction even on a wet or icy rail, suggests to me that rod driven RTR wheelsets with a plastic bushing as the axle seat will suffer accelerated failure if the load per axle exceeds 200g. Never been able to compare notes with anyone else who has done this, seems to be a minority sport in which I was sole participant!

Edited December 24, 2016 by 34theletterbetweenB&D

[Fat Controller]

 "Why are you wearing shorts, it's winter?"

"Outside perhaps, in here it's the eternal summer of the spotless mind."

 Impressive stuff when you get a lump of it. However we're only talking a 100g or thereabouts in the chassis assembly for the purposes of the model; same weight as the mazak would supply but in far less volume enabling the frame space down to the diaphragm plates to be represented.

 

FWIW, past experience of making 4mm models very heavy with lead for outdoor operation to secure reliable pick up and traction even on a wet or icy rail, suggests to me that rod driven RTR wheelsets with a plastic bushing as the axle seat will suffer accelerated failure if the load per axle exceeds 200g. Never been able to compare notes with anyone else who has done this, seems to be a minority sport in which I was sole participant!

The Reverend used to have a double-motored, heavily-weighted, Hornby Hymec on his outdoor line; with that, it was the wheels (made out of some fairly soft iron) which would wear into a u-shaped profile, almost, but not quite, ideal for fitting traction tyres.

[34theletterbetweenB&D]

The direct drive to each axle is kinder on the axle seats. The motor bogies with worm drives (Airfix, old T-H) used to chew up the axle gears before tyre wear became too severe. Hornby's spur gear motor bogie drives lasted better, I suspect because this design can readily speed equalise with each other since the drive is somewhat reversible, the tyres replaceable too, clipped on to the geared centres. The endurance and haulage 'heroes' were the Athearn and Bachmann centre motor drives; and of current UK OO I note that the Heljan 23 is up to 150g per axle. Believe that's the largest axle load in RTR OO at present.

[Forester]

34 Degrees- you must live in the same sheltered housing as my mother-in-law.

 

What did you say? 34 tea leaves? Speak up. Merry Christmas Dear.

[toboldlygo]

Was checking through my small collection of Bulleids this afternoon, I discovered a front bogie on one that was struck with the curse and boy is it banana shaped!

 

R2260 Manston - well it was once and fortunately I have a spare bogie... 

[brushman47544]

Was checking through my small collection of Bulleids this afternoon, I discovered a front bogie on one that was struck with the curse and boy is it banana shaped!

 

R2260 Manston - well it was once and fortunately I have a spare bogie... 

 

Phew.... That (earlier) version of Manston has been mentioned before... glad it's not another one. Pleased you have a solution.

[57xx]

Better still, don't deplete it and keep the U235 and it will form the basis for the next generation of live steam models. Just add water....

 

That could make double heading or MPD layouts interesting as critical mass is achieved...

[sandwich station]

Phew.... That (earlier) version of Manston has been mentioned before... glad it's not another one. Pleased you have a solution.

 

It's not just Manston it is showing up on http://www.rmweb.co.uk/community/index.php?/topic/80898-southern-pacifics-mazak-problem/?hl=manston

 

It is obviously a batch of bogies that were all made at the same time.

[JSpencer]

In the case of Hornby, Bachmann etc, we don't know if the impurity material was lead or aluminum.

 

If its lead, they could have issues meeting modern Health & Safety standards as there is not supposed to be any lead in toys and electrical items these days (unless an electrical breakdown due to weaker solder joints puts peoples lives at risk, for example in aircraft, military hardware, space hardware etc.).

 

Personally lead poisoning is only really an issue if you eat it and modern zinc based solder joints really do ensure that your product breaks down in a few years so I suspect some purpose built short life is deliberate with most electrical items (trains excluded as the uproar would be immense). I had great fun recently redoing many of the solder joints on my son's 5 year old Nintendo 3DS where the zinc had turned to dust. Fat chance I'll spend another couple of hundred quid buying a new one thanks.