7mm Geordie bruiser (NER A7)

[mickoo]

Time for another little update, the wheels arrived this week and PPD did stirling work and turned the correction etch around for me in four days allowing me to finish the build and hide my cock ups, a couple illicited the WTF were you thinking when you did that part comment, clearly I wasn't

Still, onward. No it's not getting any smaller and I think I need to get the bigger photo mat out.....which is a pain as that means I need to 'clear' even more desk space to put it down for the photos!



The last couple of days have been on the upperworks, footplate, upper frames and now the cab area, I've left one side off so folks can see inside a bit better, the rear cab, bunker floor and bunker rear only held temporarily in place for the photos.



The A7 tank inside face is contoured to wrap around the boiler and I'll be honest, a right witch to form in NS, even in the thinner 15 thou, it took nearly two hours to beat this one piece into submission and it's not my best piece of metal work, the piece fits just fine, it's my skill base which lets it down. There are two choices going forward, make the sheet in thinner material or try and anneal it, which from what I read needs to be around 1200 C° to achieve....the big blow torch is on stand by for the next side.

I've also found a nice tank top shot which will allow the next version to have more authentic rivet detail.



Cab floor in place, loosely, I didn't allow for the cusp removal so there's a small gap at the rear, I'll shunt the floor back the 0.2 mm so it's a nice clean butt joint, the gap at the front will be covered by the back head and cab internal tanks.



The sloped bunker floor fits into two grooves in the cab and bunker walls, the small hole in the top rear corners are for the vent pipes which run up through the coal space, through the cab rear and then out through the cab roof like little stove pipes, there are two more at the front inside the cab.



Good old sticky tape, holding the rear bunker in place, forming the flare on this was difficult as well, fortunately my work top has a bull nose edge which matches the require radii but it still needed beating with a hammer to form, not quite 'model' engineering if I'm honest, again another part that will probably go on the 10 thou sheet.



Front 3/4 view, the slots for the frame extensions didn't quite line up, the problem goes right back to the frame transverse stay cusp removal, the design relies on one taking the exact amount of cusp off so that the slots line up (guess who didn't), not a very robust solution so the next version will have no footplate slots for the frame extensions, which will take into account cusp removal or any vagaries there in with the frame stay widths.

Right, onward, back to the cab interior, water tanks and lockers.

Mick D

 

[tomburnham]

Hi Mick,

I was somewhat mystified by what appears to be some access doors from the cab to the coal space etched onto the cab rear. On the cab arrangement rear view drawing there will be a representation of the locker between the windows and the doors you have etched correspond to the doors to this locker. The locker and its doors can be seen on this image taken from the NER official photo of a Class W (A6) where the layout is almost identical to the A7.



And this is a similar, but not so clear, view taken of the Class Y (A7).



The etched doors will be hidden within the cab by the actual locker and it should be easy enough to fill the corresponding detail visible on the rear plate.
Tom.

 

[mickoo]

Oh ^*%&$%.....sorry I meant....oh bother

The side and plan drawings show no locker but the end view shows the doors, solid lines on one side, dotted on the other, indicating the doors are inside and not outside but not what the doors are for, so I guessed (incorrectly) doors into the bunker space.

I'll add the locker to the etch work for the next version and take it off the rear face, though on this model I'll have to rely on Milliput to cover my mess, or strip it all down again, the rear upper cab wall is a laminate which allows glazing to drop into a slot, the half etch slot being on the inner piece.

Thus I can lift off the spectacle bezels, split the laminate, clean it up and then flip it and re-affix, finally putting the spectacle bezels back on, not ideal but it'll look ok, the hole for the handle can be filled with some NS rod and filed flush.

The picture also shows very nicely the double thickness cab roof and small stove pipe vent for the left rear tank vent pipe.

Thanks for heads up....normal service will be resumed shortly

Mick D

 

[7mmMick]

Lovely work Mick, the test model is really coming together and starting to capture the proportions of the A7 well. Below I've added some images of the rear spectacle plate locker. They're from the preserved J72 and although it's a much smaller machine the locker was probably not too dissimilar in design? I've also put an image up of a J73 as well and again as in Tom's picture's you can make out the locker. I've not thoroughly researched this but every NER tank class loco I've looked at has the same arrangement;



I also love how you have represented the hinges for the spectacle glasses on the inside faces, a great bit of detail. For me though this could do with being mirrored on the outside as this is a stand out feature again on all types i've looked at, below the J72 and a crop of an A7. The three rivets in a line on the cab front leap out in what is otherwise baron plate work;





Only a minor observation pal, very excited to see your progress

Mick

 

[mickoo]

The deed is done, disassembled, flipped and rebuilt.



It'll have a wash now and then it's movie time; I'll worry about the fitment back into the model tomorrow.

Mick R,

Cheers, will add the locker to the etch work for the ALPHA model as well as the bolts and rivets etc to the cab faces, there's a few other bits and pieces to sort as well from recent info shared here, that we didn't have five weeks ago when we started the art work, every little helps especially when you don't have a real engine to crawl over.

The spectacle bezels should really be brass....for those modelling showroom NER / LNER , for those modelling BR then there's only one colour.....black!

Even at PPD's minimum sheet size I'd have enough to do 60 or so engines, that's a wastage I can't justify at the moment and have no need for any other brass work that they can be added to, I'll sleep on that aspect for a few days.

Mick D

 

[adrian]

the rear upper cab wall is a laminate which allows glazing to drop into a slot,

That is a sweet design feature!

 

[mickoo]

That is a sweet design feature!

I've struggled fitting glazing, glueing or trying to stop paint getting on them, so I pinched the idea from coaching. The W1 was the first rendition and the B1 tuned it to the standard format I now use.

You just have to make sure the internal faces are clean or they'll scratch the glazing when it's inserted.

MD

 

[Lancastrian]

You'll just need some nice wheels for the W1 now ;-)

Ian

 

[mickoo]

Right, getting there, odd how you plan it all out in your head and then when you have the bits in your hand you see an easier way of doing it

The first step was to fill in the space under the cab front lamination, I'd only made it 1/4 height (visible part) to save real estate on the etch, roughly 13p saved in material but the buggeration factor and reworks has cost me two hours, roughly £50

In short don't try and be smart and reinvent the wheel

Of course loosing the internal tank sides and cab tank cover plate to the 10 thou sheet leaves some nice big holes in the 15 thou sheet, so it all worked out fine in the end, but now means a large rework of the existing etch sheets to juggle it all about.



New cab plate fitted....all the bits are still loose at the moment.....which allows the internal tank to fit flush and allow the bridging plates (coming later) to be fitted onto a fully flat surface.

The original tank parts were used as templates to make new ones from some 10 thou sheet and then formed up to make the tank, it has promise but I won't shout 'house' until the other one is done.



To the rear of the tank is what I assume to be the crew seat, the GA show some sort of door on here but I can't be sure deciphering the drawings so left it off....wish I'd done that with the cab rear doors. Not fitting the upper cab rear does allow this sort of work to be done much easier, but fitting the cab top back might need some creative soldering.



Behind the cab door is the rear sand box tucked into the corner, I don't think the hole in the top should be there, the GA is a bit convoluted around here so it'll come put and some rivets added to match Micks 69784 photo, I'll also add the tap type flange on the side as well, no idea why there'd be a tap on a sand box?

Interestingly Micks 69784 shows the coal door as a hinged affair not a sliding one as I've done, so I need to check that out and see if that was a later change from the GA; which clearly show two vertical runners each side of the opening leading one to assume it's a sliding gate type.

Time now to tackle the other side tanks.

MD

 

[mickoo]

A quick break to watch the GP slows things but the other side is done, I'd forgotten to compensate for the thinner material so the first one was a bit short, nor did I add the bend line at the top of the side sheet to match the main tanks.

Again everything just placed in so lots of big gaps which all go when seated home with a little pressure and then soldered



New correct profile and height tank in place.



The one on the right being the correct one, the one on the left being too short and wrong profile not that the profile is that obvious from this view.



The two side by side showing the height issue and the missing flat bend part at the top on the first one, I'll reskin the one on the right and add 0.25mm to the base later on, then that'll be good enough for the test build.

I now know why I gave up scratch building all that cutting and filling and not a straight line between them

Next up the main tank inside in 10 thou.

MD

 

[Martin Shaw]

Mick
Re the tap on the sandbox. I suspect an internal pipe from the water space simply to allow the stoker to fill a bucket. Looking really good.
Regards
Martin

 

[SimonT]

They didn't really do flat plate work at Darlington

 

[mickoo]

S is for side tank, smokebox and should of been steps....but I got side tracked with some American GE muscle on Flickr

The replacement main tank internal side in 10 thou was a dream to form, scribe around the old one, cut out, bend, bish bosh done. As an added bonus it fitted in all the right places



Having fitted that the second side could go on and be tacked into place, still need to seam solder along the footplate and add some dabs where the cab front and rear walls touch (discretely).

Next up the smoke box, this is the smaller and longer of the trio as fitted to the small boiler engines, the construction concept was sound, the execution less so, too many variables for C'tain Cock Up to make an appearance so the art work will get a little tweak to make it easier to fabricate in future versions.





Next it'll be back to the cab for the last of the lockers and seats, beading around the entrance and cab doors and finally two strips along the top of the coal space sides, but not across the rear which is a little odd, but makes sense due to the angle of the flair where it would intersect the strip.

MD

 

[Yorkshire Dave]

Mick

I'm aware this is a test build and the final etches are subject to modification, corrections etc, etc. I've just been idly observing the build in between faffing with GE monsters and apologies is the following have already been considered.......

If a kit was built up as per your pictures and it came time to test the loco.... and you wanted to add ballast into the tanks to trim the loco for running how would you get into them? I see one solution would be to have rectangles in the etch which forms the top of the tank and a separate etch for the top of the tank to fit over this once trimming has taken place.

Likewise with the internal tanks will there be anyway of accessing these in order to add ballast for trimming? On the other hand there will probably be no need to as it looks like there is sufficient space under the cab floor to add lead sheet for ballast. Would this be correct for the latter?

Whilst on the subject of the tanks would it be possible to include splasher sides so fishing shot or similar could be poured into the tank for ballast without it falling through the wheels?

Upwards to the boiler. Is the intention to make the boiler up as one tube from the cab front to the smokebox rear and then leave it up to the builder to remove the desired amount to accommodate the motor. This approach allows practically the full length of the boiler to be utilised as a sound chamber. Or will the boiler be made up of three parts viz smokebox, boiler tube** and firebox. ** i.e. a full tube and not half a tube as usually seen once it reaches the tank ends .

Otherwise looking good thus far.

 

[mickoo]

Dave, good points

The main tanks have a contoured inside skin that fits quite closely to the splasher tops so would form an ideal joint for lead shot if you wished to add it, though the adhesive you use might seep out, there is still a small gap twixt frame and tank side so you could stuff something down there temporarily to stop the seepage (I'll take a photo of that area next time for y'all)

The splashers under the main tank butt up to the frames above the footplate so one side is already sealed, I hadn't added an outside wall but anyone could from the ample scrap material around the etches you're never going to see it so any old scrap rectangular piece could be soldered on.

The cab floor is hollow and is 4 mm deep with the rear splashers in there, again the sides are not sealed, but easily could be; there's a fair amount of room for a large slab of lead if required.

There is also a large chamber under the coal space that could be used for weight but that might make it tail heavy.

I will also open the smokebox front up on the next version, it's solid at the moment but a hole will go in there so weight can be added up front if required.

The middle cylinder block is basically a bath the full depth of the frames, if you added tube for the piston and valve rods then you could fill that area up as well.

The cab tanks I'd probably weight before they were fitted, like wise behind the backhead could be weighted before it was fitted.

If I wanted to weight the engine then I'd stick two big slabs of lead in the side tanks once the top, outside and front end was on, then I'd stick some dense foam in to deaden any reverberating hollow sound....and ensure if the bonding failed the slab didn't start bouncing around like some demented hippo trying to break out of it's cage. Then I'd solder the profiled inner skin on and be done, trimming would then be done in the other areas like cab floor, smokebox, middle cylinder block etc.

As for trimming, that implies a fully floating suspension like CSB for example, as far as I can tell most people opt for rigid or sprung axles which sit on adjustable screws so trimming per se isn't required but I see your point.

Boiler, the 'plan' was to make the boiler cylindrical all the way back to the firebox where it would have two sides that extend down to the frames, normally with tank engines you cannot see down there but these engines with the small boiler in will leave just under a 5 mm gap twixt tank and firebox / boiler, I'll know exactly how much is visible later in the week when I mock a test boiler up.

So, you will at least get a tube 75 x 35 mm for a sound chamber....so long as you leave the former at the firebox front out, though I could put a big hole in there so it was ring shaped as opposed to solid.

MD

 

[Yorkshire Dave]

I'd stick some dense foam in to deaden any reverberating hollow sound....

That'll be something similar to Dynamat as used for deadening car panels. I've seen 270 x 450mm sheets of Dynamat @ £6.

 

[mickoo]

Ok slow week and more going backward rather than forward to be honest.

The biggest issue has been tarnishing of the metal from the cleaning agents, more on that later. Mechanically it's mostly the little details now that take most of the time.



Pretty much all of the rear end is done, two rear hand rails and the three footplate lamp irons to add. Inside the bunker the two vent pipes need fitting and we can move forward, I still have to add the coal rails but they'll come near last as they are exposed and can be snagged easily and damaged.



Around the cab area the beading was added, it's in two parts and with careful filing and adjustment a near invisible joint can be made at the top of the opening. The idea behind the two parts is simply down to how much or little cusp to remove off the opening, too much or too little and the length of the beading will alter and being as there are two holes at each end for the hand rails then these holes must be directly above two similar holes in the foot plate. Any deviation or misalignment shows up real quick here is the hand rails are not perfectly parallel with the inset cab sides.

On the bunker rear the top flange has been added, the coal rail brackets are fitted to this later on, the cab roof is just rested on for the photos.



Frontal view, smoke box requires chimney, smoke box door and anti vacuum valve to complete, there's two oil pots to be mounted under the steps on the front as well later on. The swept up cover plate between the frames was added and tank front steps added, the balancing pipe and flanges will be next in that area.

And now the woes.



Cillit Bang, cleans like a demon, but beware, occasionally it turns your metal work brown, pretty much all of the engine ended up looking like this at one point during the week and I don't know why, some parts are fine but other areas tarnish like mad, it comes out of the sink glistening and shiny and then over the next hour or so just turns an ugly brown.

I've tried several ways to clean the nickel silver from hints and tips on jewellers forums to cutlery fanatics, all of them work fine for the first few minutes and then once again the brown rot re-appears. So far the failed attempts are thus, Cillit Bang, White vinegar, Coca Cola, Baking soda - salt - boiling water and aluminium foil....really bizarre alchemy where by the model must be in contact with the foil whilst immersed in the solution.

I did think it was the time the item was exposed to Cillit Bang so dunked some test pieces in the stuff for ten minutes, rinsed and left to dry, they are, several days later, still perfectly shiny The only true way seem to mechanically clean the metal with a fibre brush. Since the weekend I've just now washed it in warm water and detergent, which keeps it shiny but is often not enough to neutralise the flux and after a while little green dots start to appear or white smudges. If you re wash in Cillit Bang it comes up perfect again, but once dry the brown rot soon begins to return.

This evening a good soak in Sodium Bicarbonate didn't make a difference, just turned all the residual solder white, mind Cillit Bang turns it all black anyway.

I think the dishwasher might be the next choice.

Oddly the W1 suffered a lot from this, yet the B1 and 1:32 BLP have not turned even slightly brown despite being washed several times in the same process, all a bit mystifying right now, and dashed annoying.

I know the surface is smooth so will take paint well, it's just I like the metalwork to be visually clean before I get to the painting stage.

MD

 

[Steph Dale]

What are the chemicals in Cillit Bang? Something in there is, perhaps, causing the tin to be pulled out of the bronze. I'm guessing it's electrolytic and probably some sort of exchange with the solder. Difficult to try and work out through without knowing what all the chemicals are.

I'm wondering if the white fouling you describe is where the tin has gone...

Steph

 

[Yorkshire Dave]

So far the failed attempts are thus, Cillit Bang, White vinegar, Coca Cola, Baking soda - salt - boiling water and aluminium foil....really bizarre alchemy where by the model must be in contact with the foil whilst immersed in the solution.

The aluminium is there as a sacrificial anode because of galvanic corrosion with alkalines - baking soda, saline solutions (more common in marine environments where all vessels have aluminium sacrificial anodes).

Cillit Bang, White vinegar, Coca Cola are acidic and will eat the zinc in the nickel silver.

I would only wash the model with Sodium Bicarbonate to neutralise the flux. After that rinse in warm water.

Nickel silver is generally 60% Cu, 20% Ni and 20% Zn, however it can be 55% Cu, 18% Ni and 27% Zn. It is possible the quality of the Nickel Silver changed, i.e. higher zinc content, for the batch used for this etch.

When exposed to oxygen it develops a protective oxide or patina that turns a brownish-green. Nickel silver is prone to corrosion due to the presence of zinc that makes the alloy sensitive to acids and other chemicals.

 

[Steph Dale]

Dave,

Ah, that makes a lot of sense. I had forgotten that nickel silver was a brass, and was thinking it's a bronze.

My clean-up is just to use normal soap and hot water (in the same water after I've scrubbed my hands) so mildly alkaline. This helps neutralise the acid. A quick rinse under running water and it's then left to air dry until the next building session.

The only time I use anything stronger is when I'm preparing for painting.

Steph