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Rust


Kipsley

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At a very slight risk of wandering off topic: I vaguely remember a 1990s study where a scientist type person from Brazil (if I recall correctly) asserted that, worldwide, rust differs due to its geographical location - including effects caused by local biological processes - that latter point was something I hadn't thought of up to that time. Unfortunately I don't remember the exact details of his explanation (or perhaps fortunately for the sanity of the modellers on this forum).

When I did an Internet search just now, this (15 page) learned paper came up: "Ferrous materials degradation: characterisation of rust by colour – an overview" by Desmond E. P. Klenam, Michael O. Bodunrin, Stefania Akromah, Emmanuel Gikunoo, Anthony Andrews and Fred McBagonluri in Corr. Rev., June 2021 which can be read at DOI:10.1515/corrrev-2021-0005. Interestingly the authors are based in African universities: the topics of corrosion upon metal and its consequent safety and economic impacts are of worldwide concern, of course.

I suggest that people experiment with making their own rust colour paints and washes over the long winter nights, whichever hemisphere you're in. It can be a fun part of modelling.

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19 hours ago, Peter2 said:

At a very slight risk of wandering off topic: I vaguely remember a 1990s study where a scientist type person from Brazil (if I recall correctly) asserted that, worldwide, rust differs due to its geographical location - including effects caused by local biological processes - that latter point was something I hadn't thought of up to that time. Unfortunately I don't remember the exact details of his explanation (or perhaps fortunately for the sanity of the modellers on this forum).

When I did an Internet search just now, this (15 page) learned paper came up: "Ferrous materials degradation: characterisation of rust by colour – an overview" by Desmond E. P. Klenam, Michael O. Bodunrin, Stefania Akromah, Emmanuel Gikunoo, Anthony Andrews and Fred McBagonluri in Corr. Rev., June 2021 which can be read at DOI:10.1515/corrrev-2021-0005. Interestingly the authors are based in African universities: the topics of corrosion upon metal and its consequent safety and economic impacts are of worldwide concern, of course.

I suggest that people experiment with making their own rust colour paints and washes over the long winter nights, whichever hemisphere you're in. It can be a fun part of modelling.

Interesting paper. Many thanks for sharing.

 

'Yellow rust is mainly due to the high moisture environment over a period of time, which drips. Brown rust is dry, crusty and due to water and oxygen contact with localised patches on component surfaces. Black rust, the most stable form, occurs in low moisture and low oxygen environment. The causative factors of red rust are atmospheric and similar to black rust in a chloride-containing environment'.

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On 2/14/2024 at 1:18 AM, Peter2 said:

rust differs due to its geographical location

At the risk of taking this even more off-topic, the same applies to earth and mud.  I still can't believe people get away with flogging "European Dust" as though the entire continent was made of the same stuff, when I live in a county that has five significant types of soil in a few hundred square miles and at least four colours of brick.  And others asking "what does the dirt look like in France?" :frantic:

 

Coming back to the topic, it's one of the best and most informative I've seen - cracking stuff.

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On 2/13/2024 at 10:52 PM, Circloy said:

Quick wash, service, new battery & fresh fuel and its odds on it'll start first  time

No joke, that's  what happened in fact. It probably needed a new battery, though.

 

On the subject of rusty tanks. You're all wrong they do rust. 🤣 If you  leave them outside for years.

 

Check out this video. I actually came across this tank while in France and had a good look around it.

 

It's been exposed to the elements for years  and there's still very little rust. 

 

https://m.youtube.com/watch?v=CGr63DGoky0

 

Edited by noelh
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3 hours ago, noelh said:

You're all wrong they do rust. 🤣 If you  leave them outside for years.

 

Not ALL

On 26/01/2024 at 19:35, Ratch said:

I'm in the non-rusty active service school and rusty wrecks are OK too.

 

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13 hours ago, noelh said:

On the subject of rusty tanks. You're all wrong they do rust. 🤣 If you  leave them outside for years.

I dont think anyone has catagorically said they dont rust what has been said is that, due to the alloying elements, armour rusts slowly and in normal service this is further slowed by regular maintainance.

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Salad Fingers has a thing about rust. Once seen, never forgotten.

 

Nothing to see on the modelling front, but for lovers of the distinctly weird, this is right up in the top ten.

 

 

 

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On 2/23/2024 at 5:29 PM, noelh said:

On the subject of rusty tanks. You're all wrong they do rust. 🤣 If you  leave them outside for years.

The second sentence is the key here.  Outside for years.  Not just in service for a few weeks or months, maybe a couple of years at most - and apparently without maintenance.  Which returns us neatly to the original thrust of this thread.  What is appropriate and what is inappropriate.

 

And thus far this thread has done a great deal to discover and reveal excellent information on the nature of armour steel alloys and their oxidation, much of it previously largely unknown or un-appreciated.  And to help debunk the idea that everything steel rusts in a heartbeat - because certain artistic modellers have convinced us that this is so  Not to mention keeping certain related companies in business and profit - have you seen the price of MiG's U-Rust set?  £90-ish........!

 

I had been looking into armour casting hardening for a while and hadn't found some of the things revealed here.  The frequent misunderstanding of homegenous vs rolled homegenous has been usefully revealed.  The number of arguments I've had, sometimes with people who really should know better, over whether armour castings were made from rolled homogenous armour - which is of course an obvious impossibility.............  But that it turn has revealed that early production cast Sherman (and Ram?) hulls were probably not as good as later ones because of initial difficulty in achieving consistent hardening over different thicknesses.

 

All good stuff.  Keep it coming.

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On 1/26/2024 at 6:30 AM, Kipsley said:

Posted in another forum about a guy who had some (pretty good) rust effects on his tank. His post read: "please comment freely as I'm still learning". I pointed out that rust on tanks in active action was almost unheard of during actual wartime. The tank generally just didn't survive long enough to actually accumulate rust. That and the constant grinding of metal tracks through dirt, dust, and sand would leave tracks metal and bare, and relatively rust free. Average life expectancy of a battle tank in a war zone was measured in hours, sometimes days. A few might survive a few weeks.

 

But even during peacetime, those of us who have ever served in the military would know that equipment was constantly being cleaned, repainted, tested, practiced with. It just never sat idle. A modern Abrams would never be allowed to rust during peacetime (or some poor sappers are going to find themselves cleaning that tank with their toothbrushes at 3am).

 

So while Mr "I want to learn" took offence when I pointed out the above, what do you all think about rust on a tank?

 

I have seen dioramas of abandoned wrecks and such, but that's just different IMO. I'm talking about active, working, in the field, tanks.

Don't know if this will help or harm, however I am in agreement with you. The following backs up your observations/experience as it is what I saw as well. It depends on the nation in question, their maintenance practices in general, quality of their vehicles, where the vehicle is stationed, what the people and leadership of the unit are like and age of the vehicle as well as that military's budgets. The National Guard M109 Paladin unit I was in rust was minimal and rarely seen in part due to the armor being stationed in Ft Hood Texas where it is dry as a bone and in larger part due to maintenance. But they were definitely dusty! Drive through a wash rack 30 seconds later bone dry and able to fry an egg on it then 30 more seconds dusty!

 

Compare that to Ft Polk Louisiana in swamp and bayou country with seasonal rains they were a little bit more rusty but still lightly. Usually in areas that did not see many "touches" by hands, rear ends or feet like in nooks and crevices or some areas in the engine compartment. But overall in the US and most western nations they are well maintained and when rust became more noticeable we had touch up paint so you are more likely to see mismatched patches of fresh paint than rust.

 

The US military definitely has hard maintenance schedules that were not missed with constant PMCS checks and tasks and will rotate a vehicle or weapon out to a depot for repair, refurbishment or overhauls and the very rare upgrade to newer vehicles. Smaller vehicles like the CUCV's (Commercial Utility Cargo Vehicle) aka 1980's Chevy pickup trucks and Chevy blazers for our civilian friends here, had more rust but more inside than outside and always that "rubbed smooth" dark metal/brown look not the orange-ish streaked look.

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On 27/02/2024 at 09:11, Kingsman said:

I had been looking into armour casting hardening for a while and hadn't found some of the things revealed here.  The frequent misunderstanding of homegenous vs rolled homegenous has been usefully revealed.  The number of arguments I've had, sometimes with people who really should know better, over whether armour castings were made from rolled homogenous armour - which is of course an obvious impossibility.............  But that it turn has revealed that early production cast Sherman (and Ram?) hulls were probably not as good as later ones because of initial difficulty in achieving consistent hardening over different thicknesses.

As indicated earlier I'm now involved in the production of super-alloys (Ni & Co based as opposed to Fe based) but the processes are identical. During the casting of alloys it is possible that pockets within the cast ingot have different concentrations of the constituent elements which would lead to differing properties (strengths etc) throughout the final product - not good in any application. As a result all our ingots go through a process where, once cast, they are re-heated to temperatures that get close to their melting point and held there for a substantial period of time. This allows the elements in any pockets to disperse evenly throughout the metal and thus giving consistent properties throughout the end product, a process referred to as homogenisation. I don't recall this being employed in the production of armour plate.

 

I'm not sure that, due to their large size, material type (i.e steel Vs nickel), production needs, etc. that the cast armour bodies/turrets would have been homogenised in a similar way. Similrly I'm not 100% certain the hardnesses usually seen with armour plate can be achieved with cast armour. It is the rapid quenching from hardening temperatures that fixes the steels structure in the hardened & stressed state, followed by tempering which reduces the stresses, in plate of costnt thickness this is easily controlled, in castings of varying thicknesses not so. Add to this the already brittle structure of the cast (i.e. non-wrought) material probably explains why the early castings were poorer performers than later ones.

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@Circloy I believe that was one of the processes used by the US on armour castings, as mentioned here some time earlier. Can't recall who brought it up. They would typically undergo 3 or 4 heat treatments at different temperatures and durations with at least 1 quenching.  The whole process took about 2 weeks.  Their initial problem was differential cooling of different thicknesses leading to inconsistent hardness.  The cure as mentioned earlier was to use water jet quenching rather than a still water tank.  Obviously a homogenised ingot would be disrupted to some extent by being re-smelted for casting and the process would need to be repeated on the cast item.

 

As for plate armour, again the ingots would be processed but this time into sheets of appropriate thicknesses by heating and rolling.  The question is whether re-homegenisation would then be necessary.  And how that is accomplished without distorting the smoothly rolled plate.  Re-rolling would defeat the process.  Presumably the homogenisation process on thinner plate compared to ingots is quicker.

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Thanks @Kingsman I thought I'd seen somthing mentioned, couldn't recall where,

 

As for re-homogenisation of plate it's not required, the mechanical processing (hammer forging, press forging & rolling, etc.) serves to homogenise the structure of the metal.

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Referring to the post above about M109s, they were and are aluminium for the main structure. So no rust. Some bolted- on fittings were steel, probably "mild": not armour.

 

You would be surprised how many people feel the need to apply rust to models of aluminium vehicles like M109s, M113s, CVR(T)s etc.

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On 04/03/2024 at 10:46, Kingsman said:

You would be surprised how many people feel the need to apply rust to models of aluminium

Old Sheffield saying: "You can't educate pork"

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On 04/03/2024 at 10:46, Kingsman said:

You would be surprised how many people feel the need to apply rust to models of aluminium vehicles like M109s, M113s, CVR(T)s etc.

or fibreglass or even to concrete

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