4mm The Sentinel (and derivatives) in EM

[AJC]

Thanks David - the Thomas Hill and the 'modern' Hunslet DH (this isn't it) both have very funky handrails which were the very devil to get right does indeed have a Loadhauler, all 108:1 of it. Having sorted a problem with one of the cranks, and trued up the flywheel (it's amazing the difference this makes) dad has managed to persuade it to run really rather well. I knew it had the potential to do this, I just couldn't quite find the problem.

Now the weather has improved it may even get painted. I'm toying with the notion of all over wasp stripes or a more sober colour, blue possibly.

I managed a little more work on the Sentinel on the Bank Holiday getting the chassis ready for it's mechanical fit out but, before that can happen, I need to get the brake assemblies sorted and find some thinner wheels. The (Markits?) ones supplied are quite nice but a touch thick over the treads for my liking. Since they're also plain discs and at least some of the 200hp machines - seem to have had 3 hole discs or similar there's an obvious solution to be had. Thinner wheels will also make the brakegear (which goes on both sides of the wheels) very much easier to make and fit.

Adam

 

[Steph Dale]

I managed a little more work on the Sentinel on the Bank Holiday getting the chassis ready for it's mechanical fit out but, before that can happen, I need to get the brake assemblies sorted and find some thinner wheels. The (Markits?) ones supplied are quite nice but a touch thick over the treads for my liking. Since they're also plain discs and at least some of the 200hp machines - seem to have had 3 hole discs or similar there's an obvious solution to be had. Thinner wheels will also make the brakegear (which goes on both sides of the wheels) very much easier to make and fit.

Adam,

Might I suggest going for Black Beetle wheels (available from Branchlines)? The RP25-88 ones have nice thin profile (0.088" funnily enough! So a shade over 2mm) and are turned nickel-silver. I've used an awful lot of them to rewheel my HO diesel locos and consider them well worth the money...

Steph

 

[AJC]

I had thought of that Steph - and may yet since Expo EM is in a couple of weeks and I'm unlikely to have a huge amount of modelling time between now and then - though I do have the wagon wheels in stock. In fact, before this kit was announced I had a set put by for a proposed scratchbuild. Can I find them? Have I used them for something else? Can I remember? What d'you think?

Adam

 

[AJC]

It has been a long time coming but over the Christmas break, some visible progress has been accomplished and the prospect of a running chassis is not too far away. One the way, I have made a couple of alterations towards transforming the Radstock Sentinel into my chosen industrial type.



My normal practise is to paint loco chassis once the basic frames and key details have been added. I have ever really understood why anyone would get a locomotive fully up and running before stripping everything off in order to paint it; much better, so far as is possible, to make the thing work once. In this instance it's essential; the chassis relies on a gear train whose gears are secured with Loctite. Without chemical blackening, there's no other straightforward way. The only other amendment made is to use the copperclad provided to mount the front pick-ups to add a motor support bracket. Given that both motor and gearbox are provided I admit to being slightly surprised that there's nothing in the kit for the purpose. Everything is rigid so the motor can be stuck to the bracket with a blob of blu-tack or silicon sealant when the time comes. In the meantime, the gearbox has been gently run-in on the bench and is now ready to fit.

The loco in what passes for one piece looks like it should be on a back road on a preservation site. The footplate wanted a notch taken out of it to clear the gear train, just a small one. Above the footplate I've fretted out and fitted a new cab front. Working without a drawing the dimensions of the windows are guestimated from photographs and by mapping against known angles and dimensions. The bottom of the windows align with the vertical centre of the cab cutout while the top coincides with the top of the side sheet. The angle of the bonnet looks to be 45o and from this you can project roughly what the remaining horizontal and vertical measurements should be.




Edit: I now see that I have managed to solder the axlebox castings on the wrong way about (for my chosen prototype, they're absolutely the right way about for the Radstock pair). I've just amended this and taken the retaining nut off the front: I need the space for the flywheel.

That's all for the moment, more in a bit. For the record, the Thomas Hill has had a coat of etch primer, a top coat will happen once the weather is more reliable. At this rate, the Sentinel will catch it up. Happy new year.

Adam

 

[AJC]

Happy 2014! Having fitted the remainder of the gear train, the gearbox and motor, I reached that ticklish stage in any locomotive build whereby two apparently sweetly working mechanical bits come together to make a working chassis. Often, this is where everything seems to go wrong, but running the mechanically complete chassis upside down stuck to a lump of blu-tack on the trusty - and very ancient - H&M Powermaster suggested that the rolling chassis would still function with a motor attached. Suitably reassured, I went about adding pick ups this morning and, just for once, a new chassis worked on the first time of asking and, glory be, wired up to travel in the correct direction! A little tweaking of pick ups later and the thing runs reliably, quietly and at an appropriately sedate pace. Very satisfying.



The leads from the motor are temporary - the motor needs to come off and have a couple of mm taken of the outer end prior to getting a suitable flywheel fitted (dad has very kindly offered to turn one up).



Adam

 

[AJC]

And here's where we're at. It's hauled its first (small) train.



Adam

 

[AJC]

A day off, and the horrid weather hereabouts resulted in the soldering iron and piercing saw coming together to sort out the curves of the Sentinel's roof. This is a major departure from the kit as designed, partly because I wasn't all that keen of having the whole roof assembly removable (as designed) since the outer sections of the roof at least were very firmly riveted to the tops of the sides and partly because Sentinel had an aversion to building two batches of locos the same.

The kit, of course, is meant to be for the pair bought by the LMS for the S&DJR - http://sentinel7109.blogspot.co.uk/p/7109-vs-radstock-sentinels.html (links to what I'm actually building can be found in post #12 of this thread) whose roofs met the cab side sheets by means of a 120 degree bend. Most of the industrial variety had curves going through a mite over 90 degrees and, it transpires, lots of other subtle differences between batches. If you follow the links in the first post about this Oh, and either the cut out in the cabside is too small or the cabside itself is too tall... Actually, for the post-war type I'm building, I think that the cutout is probably about right, but for the locos that the kit is supposed to depict it needs to be opened upwards by about 1mm (it is notably bigger on the Radstock pair to what seems to have been 'usual' so I took 1mm off the top of the cabside so that it finishes a little below the tops of the window in the top of the cab front sheet.



So, here's the current state of play. The sharply curved bits are rolled from the supplied roof. This is about 3mm longer than it should be and overhangs extravagantly as a result; unfortunately, I neglected to take any pictures before I trimmed these bits to length. For convenience, I scribed a line 3.5mm from the outer edges of both sides, rolled the curves while the roof was in one piece and only then parted the sections off with a piercing saw before tidying up with files and soldering these to the tops of the cabsides leaving a nice, shallow arc in the middle which I bridged using a bit of 10 thou' Nickel Silver sheet cut and filed to be a drop in fit. This is complicated by the pair of holes that have to go in. The first is for the chimneys (these latter are a good 2 and a bit mm too tall) while the second is for the - very necessary on the real thing - ventilator which was to a different pattern to that on the S&D pair and thus in the box. Following the prototype, the middle bit is removable; how else would you get the boiler in/out?



The tongue you can see is part of the fixing system. This underside view might make matters clearer:



The aforementioned tougue clips under the structure on one side while the other is secured by a couple of clips made of 1mm milled angle. Two bits are soldered back-to-back in a sort of 'Z' and engage with a length of 0.7mm wire soldered under the roof for the purpose. Two more bits of angle stop the roof from sliding back and forth. Now in theory, this should leave two quite visible joins...



...and if it weren't for the (prototypical) angle iron rainstrips, it might. This is all good fun, apparently.

Adam

 

[AJC]

Among the other projects I have on the go, the Sentinel has progressed a little, to the extent that almost soldering is now complete. The cad doors and handrails have gone on - thank you to Steph for giving me the steer on BH Enterprises' 0.3mm handrail knobs. These are appreciably finer, just like the real thing.



The bonnet in its earliest stage trial fitted to the metal parts. It's been treated to a dose of filler and will have a coat of primer before I do anything else to it. It clips on at the minute but will be glued on later with epoxy. First, however, it seems that I misjudged the cab front sheet windows slightly and will have to fill them in slightly to suit. Not ideal but not too much of a challenge either.



The rear view shows that I've treated the cab rear to replacement lamp irons from Masokits. These are much more durable that those supplied (though there was little enough wrong with their appearance). Basically these consist of 5 thou' brass folded back on itself and soldered to a length of 0.45mm wire tidied up with a file. the result is more or less bomb-proof and is my preferred solution for exposed lamp irons such as these.

Adam

 

[AJC]

Having primed, filled and rubbed back a few weeks back, it was deemed safe to add some detail to the bonnet. After an evening or so back at work on it this is where we've arrived. The various elements are the covers for the engines, filler cap for the water tank and a couple of scribed panel lines. Seems simple enough but required a fair amount of careful work. Oh, and I sorted out the bottom of the cab front windows to correct my error in making them a smidge too deep.









It's coming on. Doors and handrails next.

Adam

 

[AJC]

The next, and possibly the trickiest bit so far as the overall look of the model is concerned, area to be tackled are the numerous doors along the bonnet. This is another area where these steam Sentinels are akin to diesel practice; the pair of doors at the front were to get at the engines, the rear ones were access to the various water valves and so on and possibly the additional bunker that the smaller locos had.



I had initially thought about cutting the flat strip beading for these from 5 thou' sheet and, while I found that I could achieve something like a consistent result this way, as you can see in the foreground, getting the thing out of the sheet flat and intact proved too difficult. Plan B was called for and appeared in the form of Evergreen 10 thou' x 20 thou' strip which is too thick and will have to be sanded back later. Only then will the final details be added. That said, the initial results are encouraging, everything is even and straight and more or less the right size though without a proper drawing this is all in the realm of copying photos and guestimation. We shall see how it looks under a coat of primer. Not bad so far I think.



Adam

 

[AJC]

More incremental detailing - you lot may not be over-excited by this but for me, the gradual build-up of minor detail really brings the thing to life. In fact, there is very little left to do; some panels on the cabside, sandboxes, pipes and couplings and then paint. The Thomas Hill that started this thread is still in primer...





Adam

 

[AJC]

The loco has now reached the stage where all the various sub-assemblies are in primer and two have made it as far as top-coat. One is the centre-section of the cab roof which isn't all that exciting; it's plain black. The other is the boiler,superheater and funnels [Sentinel engines had funnels, rather than chimneys] seen here after a coat of primer and another of matt black:



And after a few washes and detail painting. All this is likely to be more or less invisible:



Adam

 

[AJC]

And for those of you modelling in 7mm, some idea of scale:





Adam

 

[Dikitriki]

Where do you get the giant Humbrol tins?

Nice work though. I'm not entirely sure where you squeeze it in.

Richard

 

[AJC]

Where do you get the giant Humbrol tins?

Nice work though. I'm not entirely sure where you squeeze it in.

Richard

Thanks Richard. You can get 50ml tins of some colours, believe it or not! Like all 'conventional' Sentinel locomotives, the boiler lives vertically in the cab. There's a GA here:

http://sentinel7109.blogspot.co.uk/p/7109s-engines.html

Just like the real thing (on this occasion), this will be craned in through a hole in the roof.

Adam

 

[AJC]

All the bits have now had a coat of primer and, where appropriate, matt black. There are a few areas that will require a thin coat of something to cover a couple of areas where the metal has made a reappearance. The final colour will be a mid-green, representing Sentinel's works scheme and, in accordance with that, lots of orange and black lining: it's sort of what the Great Western got up to with a different shade of green. The benefit, of course, is that I can use lining transfers (Fox, 2mm scale).





Adam

 

[AJC]

Moving on, I've decided to complete the painting by hand. The model is so small that this is easily achievable to a good standard. The main livery colour will be applied in several very thin coats. After the first - straight Humbrol 30 - we get a clear sense of where we're going.



The remaining coats will be a custom mix of the same Humbrol 30 and Humbrol 80 at 2 parts to 1 followed up by Klear and transfers. Note the (prototypical) pink undercoat on the buffer beams. Here it is after the second coat.





It appears a bit darker than this to the naked eye and probably wants at least another coat, possibly two, before the Klear goes on. You can also see that the inside of the cab has been treated to a two-tone black and (off) white.

More marking...

Adam

 

[AJC]

... and marking done, I've been attempting to work out the detail painting 'to do' list. Based on the few pictures on the web and in my collection which show - or appear to show - Sentinels in the paint scheme in which they left the works in Shrewsbury, I have arrived at the following:

BLACK

Engine covers
Handrails
Couplings
Valence (see above, I've got that wrong...)
Outer edge of buffer beams
Lamp irons
Possibly the water filler (if anyone has access to Frank Galbraith, the NRM's Sentinel currently in Hull, restored to what looks more or less like a factory finish and can clarify this...)

Lining: there is an an unfeasible amount of this, including cab doors, all cab panels on sides and rear and bonnet sides and front. This will be one fussy looking paint job when it's done. Some locos appear to have had the edges of the buffer beams lined out as well. That's a step too far.

Possibly all this - their standard finish - reflects their background in commercial vehicle production, possibly it seems strange because we are so used to seeing industrials in very plain schemes in preservation and in their latter years in service when customer repaints were normal and cleaning often an unnecessary indulgence?

Works photos suggest that this fussiness was quite common among industrial builders. Barclay were particular exponents of it:

http://www.eastsomersetrailway.com/gallery.php?gid=53
http://www.gracesguide.co.uk/File:Im1905V100-p420.jpg
http://tanfield-railway.blogspot.co.uk/2013/11/horden.html

It even continued post-war (not that you can really tell and I'm sure that the wasp stripes were not applied in Kilmarnock!):

https://www.flickr.com/photos/52467480@N08/6454483793/in/set-72157628278328931


Hunslet's house style was also very distinctive. Ring Haw, shown in the link below is painted according to what Don Townsley says was 'normal'. Note that the base colour is black and the coloured panels, particularly on the saddle tank, are relatively small:

https://www.flickr.com/photos/52467480@N08/6454365177/in/set-72157628278328931

Perhaps this suggests that we, as modellers, should make more of an effort? These builders certainly got their money's worth out of their painters...

Adam

 

[AJC]

And finally, in this morning's sunshine:





Ok so it still needs glazing, a driver and some weathering but with the lining, picked out bits and bobs and the chassis elements painted it looks complete enough.

Adam

 

[AJC]

It seems that no finished picture of this loco has appeared on the forum, s here's one to be going on with since we've had a bit of sunshine this afternoon.



Happy Christmas

Adam