7mm Mickoo's Workbench -WS 72xx - MoK Urie King Arthur - JM LMS Garratt

Discussion in 'Area 51' started by mickoo, 8 September 2018.

  1. LarryG

    LarryG Western Thunderer

    When my late friend Johnny Walker had brass Black Fives and Jubilee's mass-produced in Taiwan, a handful of of other types were also produced including Ivatt Class 4's. The latter's body could not be separated from chassis because a pipe under the running plate had been soldered to the chassis. An easy fix of course, but it shows that some of these American inspired designs took some thinking through when produced in model form.
     
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  2. mickoo

    mickoo Western Thunderer

    Once again, the fat lady has sung, sans backhead....which I now always do as an de-fragging post model build whilst the model is away for paint....the MOK 4MT is complete. Time for a bench clean down and reach for the next box ;)

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  3. cmax

    cmax Western Thunderer

    Another stunning build, it does seem a shame to cover it with paint, but I'm sure Warren will do his magic.

    Beautiful.

    Gary
     
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  4. Scale7JB

    Scale7JB Western Thunderer

    Very nice..

    JB.
     
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  5. mickoo

    mickoo Western Thunderer

    Cheers, it really does need painting, it's been a long build and even the nickel silver is beginning to tarnish, mostly where the soaps and cleaning agents attack the solder and fluxed areas. I'm still looking for a cleaning agent that cleans and doesn't tarnish as a by product.
     
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  6. Deano747

    Deano747 Western Thunderer

    As usual, another masterpiece! The pipework is really impressive.

    Regards, Rob.
     
  7. Deano747

    Deano747 Western Thunderer

    I use Viakal or equivalent and never had problems, but you're the professional and I'm sure most likely tried many products.

    Regards, Rob.
     
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  8. mickoo

    mickoo Western Thunderer

    Rob, I've used Viakal in the past and found it to be one of the most aggressive, I tend to use Limelite these days but even that creates staining long term. I've used pretty much all of the kitchen cleaning agents and all tarnish the base material.

    On brass they either turn orange or in some cases pink, on nickel silver you get a brown tarnish, almost like a nicotine stain and after a while it looks:shit:, it's smooth and once painted is invisible, but in bare metal they look awful.

    It's an elephant in the room that keeps occurring in a cyclic pattern.

    One thing I have heard being used is basically enchant, pretty aggressive stuff, use outside at arms length for short periods. I'm pretty sure it's what the Koreans use on their brass models before lacquering them.

    Whilst stripping down the UP Challenger tender I took a laminate part off and cleaned up the solder to notice a very thin raised bit of metal that matched the solder blob, almost like the surrounding area of brass had been etched away, perhaps 1-2 thou; it wasn't a defect in the material surface as several similar areas were found later.

    Going to those lengths is extreme and not worth the risk or effort, but I'd like to find out what it is in the kitchen cleaning agents that having an adverse effect, it may even be the flux I am using, the two could be reacting and staining the metal.

    Most of the time now I just use plain water or fairy soap and then rinsed liberally, even then, over time, a stain begins to leech through.

    Professional....ha :D never been called that, competent dabbler more like :))
     
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  9. mickoo

    mickoo Western Thunderer

    The pipework is a test in patience and fortitude, there is no other way to describe it :p
     
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  10. simond

    simond Western Thunderer

    Most fluxes and descalers tend to be acid. I think it’s true to say that most detergents are alkaline, and most dishwashing liquids contain something that’s nice on your skin. I think it’s also true to say that clean metals will oxidise in the air, some very quickly, like aluminium & stainless steel, some rather more slowly like lead. I guess the brasses are somewhat slower still to build a visible oxide layer, but I think they do anyway.

    The “make your hands soft as a baby’s bum” stuff might stick around through the rinsing, but otherwise I’m not sure that the washing compound makes a massive difference, provided it’s thoroughly rinsed off.

    polish it, photograph it, paint it & photograph it again, so we can enjoy it one more time!

    any metallurgists out there?

    cheers
    Simon
     
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  11. Max Midnight

    Max Midnight Western Thunderer

    Phoenix make this point in their painting guide for the etch primer:
    'DO NOT use washing up liquid as it contains a chemical coating to ensure that crockery etc. ‘sparkles. Whilst this coating is harmless for most purposes it reacts with paint and primers causing problems for the unwary modeller.’.

    Not sure if that helps or hinders? :headbang:
     
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  12. mickoo

    mickoo Western Thunderer

    Yes I've heard that before but never had any problems, my go to painter hasn't either; that could be down to both of us mixing our own industrial cellulose etch primer as a base coat.

    All of my models at some point in the build....most of it actually....have been washed with soap, not necessarily washing up liquid (occasionally) but more so hand soaps from those handy dispensers. Most get at least one wash with a kitchen cleaner but due to their aggressive staining after a few days I tend to leave that to nearer the end.
     
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  13. dibateg

    dibateg Western Thunderer

    I always just wash with water - sometime several times during a session. It also of course depends on what flux you are are using, I only use the citrus based stuff from building 7mm on line. Although my models are not finished to your standard Mick, they do keep very clean. I always wonder why people use these strong and 'cheap' fluxes from a DIY store - why? On a £1000 pound model railway engine? Why? !!

    The only thing I use is Jif ( or equivelant ) before painting and then the model is thoroughly rinsed and left in the airing cupboard for a day at least. I never leave 'sealed' voids in my models, and always drill a vent hole, sometime they seem to hold water for days without any extra heat!

    Regards
    Tony
     
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  14. mickoo

    mickoo Western Thunderer

    It's hard to photography but lets try this.

    This is the inside of the MR Compound tender, as such it does not need to be clean or neat, thus the solder work and flux application is rather tardy.

    IMG_9805.jpg

    I've not soldered every tab as it's a test build for fit, this assembly was washed in CIF for 60 seconds before rinsing, however there was already tarnishing from previous washes, the CIF just amplified it.

    I found nearly all kitchen cleaners turn solder dark grey and matt them, the pinky tarnish is around each solder joint where the flux would have been, I do tend to 'wash' the joints with solder even with a small tipped brush.

    The top side and right side bolster have just been cleaned with a fibre brush so it is only surface deep and cleans off relatively easily.

    What this model has not suffered from is the browning of the surface that I see in some kits, I'm wondering if that may be down to the base material. I have no browning on my tender test build, yet the King Arthur tender but at the same time is slowly turning brown.

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    It's not easy to see, but the MOK metal is not as bright as the PPD metal, I'm not worried about the excess solder at the rear of the King Arthur tender as it will have a full load of coal, but elsewhere you can just see the beginnings of the brown stain creeping in from the edges.
     
  15. mickoo

    mickoo Western Thunderer

    Tony, for years I used the exact same flux and am now using the one recommended on WT Safety Solder Flux a few months back (I bought a litre which will last a few years, I still have two bottles of the BOG stuff as a reserve) as the BOG stuff was getting hard to come by.

    It's cheap as chips and very good with regards to soldering and flow, easily an equal to the BOG stuff. I'll be looking at building 8 - 10 models a year shortly so I need a ready and reliable supply....hope neither of them have a shelf life :eek::D

    The tarnishing I used to get with BOG stuff as well so that's not a difference between the two.

    I'll easily wash three or four times in a session, but usually with soap, I may just try with hot water on the next build and see how that goes, it's a brass model so you get about three weeks before the metal naturally tarnishes.

    My standards :p, don't knock yourself, I've followed your models for years and they were and still are a rock solid benchmark :thumbs: and as we all know, clean models mean diddly squit once painted. So long as they are mechanically clean and smooth, then eliminating the tarnishing is nowt more than a folly ;)
     
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  16. mickoo

    mickoo Western Thunderer

    Does anyone have a decent sized GA for the 72xx or did it get printed in the GW Journals, if so, which one so I can grab a copy.

    The kit has the extensions and a tapered rear to the frames, but I'm not sure that's authentic looking at the preservation restorations.

    Thanks in advance.
     
  17. simond

    simond Western Thunderer

    GWRJ Issue 18, but no drawing.

    You have mail
     
  18. mickoo

    mickoo Western Thunderer

    Appreciated, I'll keep looking, there must be some somewhere as they appear to be a popular subject.

    Must confess I've had a sneaky liking for them....even though they are GWR....but if I were building one then I wouldn't start here :eek: there's going to be quite a lot of scratch building and I may just not bother and get new etches drawn up, especially for the tank sides, the kit ones are 0.7 mm and you have to blind punch all the rivets from a paper overlay; then, bend them at the front to meet the boiler :))

    On the flip side, the castings look to be very good on first inspection.
     
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  19. Yorkshire Dave

    Yorkshire Dave Western Thunderer

    Apologies if you already know this but just throwing some thoughts around ;).

    I would use tepid rather than hot water if you reside in a hard water area. Hot water increases the release of limescale which may (as daft as it sounds) leave trace deposits on the model. In addition limescale contains traces of iron which could be the brown staining at the solder joints.

    If you do have a water softener installed this may not totally remove the limescale and other trace elements.

    The harder the water the more soap/detergent is required for cleaning. I remember when we lived near Ipswich many moons ago the water was quite hard as the kettle was forever furring up.

    After scrubbing and cleaning the model with the detergent you normally use I would rinse the model under the cold tap to remove the detergent. Before this I would prepare a final rinse of tepid or cooled boiled water from the kettle as this would have most of it's limescale and trace elements removed. Then shove the model in a warm atmosphere to dry i.e. airing cupboard.

    I believe the natural oxidisation process of tarnishing has been covered previously which as we know is affected by atmospheric conditions but this could, at a chemical level, be hastened by any trace elements left on the model after cleaning to act as a catalyst for this process. Also, as we apply heat to the kit during assembly we are altering the structure of the metal at a molecular and atomic leve in these areas. All subtle changes which may alter the oxidation process of these previously heated areas.
     
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  20. mickoo

    mickoo Western Thunderer

    Dave,

    That's a good point, the water is rather hard around here, I'll try cleaning it with cooled boiled water on the next model. We also have a dehumidifier in the house which gets emptied almost daily, I might try washing it with the water that recovers and see how that goes as well, by rights there should be very little limescale in there.

    It is certainly only the areas that get heated and have flux on, the rest of the model is fine....if the metal comes from PPD, MOK white metal does seem to turn brown over time. My B1 test build is over two years old and has not browned at all, or very little, so the PPD material does seem more stable in that context.
     
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