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Whilst looking at the plans in MR and the photo's in the new 'South Park' book, I noticed that the join between the sections at the bottom of the upper tapered cone, was both thicker and wider than I expected. On the full size version the parts could be separated here, and this join is bolted together with lots of bolts - which if they were made to scale are too, too fiddly to replicate!Not so the flange which is what I noticed, so after some experiments I settled on a couple of pieces glued 'edge to edge'of .75mm square plastic section, making this then 1.5 mm wide. I think it looks more like the photo and is now the equivalent of 1.2" wide, and is at the lower edge of the upper tapered part.
The above is a photo of the smokestack and its fixings complete except for painting. The scratch built headlamp bracket is 1.25mm thick (.050), made from laminated plasticard on each side, the hole in the brackets allowed me to use a pair of pliers to bend the bracket to the required shape. They are fixed and glued into the smokebox sides with four small 12BA bolts, these are then also glued in to ensure they stay put. Interestingly it needed a couple of tapered fillers against the smokebox to level up the sides, the plate that the headlamp sits on is made from 2.5mm thick plasticard (2 x .050), checks were made with a spirit level to ensure it was level in both directions. At the front is a piece of 1.5mm brass rod held on with a couple of tiny brackets an above the brackets are a couple of pieces of brass tube, sloping outwards in two directions - these are the flag holders. The large oil headlamp will also be scratch built and described later.
The smokebox (internal) crossmember helps to keep the big smokestack nice and vertical, it remains removable, for access to the fiving screw if required. The small circular plates on the sides of the smokebox are for the pilot deck braces; these are glued in position, add the three fixing rivets per plate, and the central hole through the smokebox wall. The braces themselves will be made from the larger (steel) bicycle spokes in due course.The inner piece of the cab front can be seen, being tried for size, the whole scratch built cab will be described later. Thanks are again due to David Fletcher for the PDF's that I worked from. There are two styles of cab, this one is as David Fletcher's: there was another style that had a single horizontal panel, as shown in the ex-works photo of the moguls, but the photo's of number 69, which is what my loco will be, show this style, so that is what has been built. The photo of 69 which appears in both the 'Mineral Belt' and the 'South Park' books is said to be of 69 in 'virtually new' condition but it has a different to the official photo style cab. I wonder how they smashed up the original one so soon? Another possibility is that not all of these loco's were supplied with the same style of cab when new.
The smokebox, has a large 2 part casting containing the cylinder exhausts below it on the prototype; this I made from plasticard 1.5mm thick, add the extra fixing pieces at each side, then add the small brass nuts to replicate the fixing bolts from the casting to the smokebox, add some plastic for the bolts going through the smokebox side to keep them in the right location. The base is hollow and will fix over a plate on the cylinder unit to keep all in the correct location. Through the centre of the smokebox (& plate) is a fixing bolt (from a machine screw), accessed from the hole for the smokestack. Add the base plate for the smokestack from a plasticard disc and plasticard bolts around its edge. The handrail stanchion locations are plotted next - hold the boiler unit steady on the bench, and in a position with the upper centre line in a correct vertical position.Working from a drawing plot the locations for the 4 stanchions - these will be from the original loco body. Double check the locations twice they are critical and difficult to do as the smokebox is a smaller diameter than the rest of the boiler! The stanchions will not fit directly onto the boiler - they need some 5mm wide strip that is screwed to the boiler, and then bends to a horizontal position to accept the stanchion. A lot of 'trial and error' is needed here and the stanchions also need to be carefully drilled to accept a fixing spigot/screw after removing the old fixings pin as well. I found that the boiler strips are 10mm long the two for the smokebox a small amount extra in length - it is close to 13mm long here. The strip is 24 thou. thick I believe - it was from some scrap strip from etched brass kits.. Paint the strips black, and then store them carefully away having marked them with what they are. It will be a long time before they will next be needed, keep them with the handrail stanchions but do not fix the straps and handrail knobs together.
There are a couple of globe valves where the water enters the boiler; these are made from 6mm plastic spheres with 3 holes drilled into them for the water in, fixing to the boiler, and the last one for the valve to switch it off. The first two are at a right angle; the last one is vertical from the other two. For fixing it to the boiler I used a panel pin glued to the boiler with an 'epoxy resin' glue. The valve wheel is the male part of a 6mm diameter press stud, fitted over a pin as the fixing, the feed pipe is from bicycle spoke being 1.9mm diameter so a 2mm hole is needed for this, the pipe will wait till later. The position of them is from the drawing. The final addition for the boiler is the Westinghouse pump, this is fitted on the engineers side, and is basically the Bachmann one, with slight modifications, these are described later. At the moment we need a fixing for it; this is a complicated assembly of strips in a rectangular shape, made from plasticard fitted over the curved boiler cladding, that needs to be vertical to the boiler - make a small label and put it on the boiler to remind you of its general position, as it is much better to get the location for it right when the stepboards have been made and fitted later.
It was now time to make the domes, with the curved shapes; on the prototype the domes were made from iron tube and castings for the fancy rings, these loco's were amongst the last to have these - things were simplified and the replacements were much plainer. For making my fancy rings I used my electric drill as a very simple lathe, and tried shaping the tops of these domes. Before this the discs were glued up from circles of 1mm plasticard and left overnight for the cement to dry.The results were quite good, there was some filling was needed, but 'not a lot'. The filler is some from the Military Modelling groups, and is called 'Mr Surfacer' - by a Japanese company - 'Gunze Sangyo'; it is available in three types, depending I think on the grain size. I have used the larger (grain)size one - called '500', the other is '1000', there is an even finer version as well called '1200'. It is rather like cellulose car body putty, (and has a strong smell as well!), but much thinner. It dries fast and can be cleaned out of brushes with Isopropyl alcohol. I used the '500' version, it can be bought from Lou Stener, via the web (link - http://www.armour-models.co.uk).
A close-up of the dome tops, and also the safety valve top, with the whistle, which is in undercoat brown. The whistle is a collection of various bits of tube and plastic, all fitted together on a spare piece of bicycle spoke. The blue grey is the 'Gunze Sangyo' filler. Here are the results -
  
The photos show them 'just placed' in position, they need some final work, and the lower bit of the sand dome is the wrong way round - the small slot (for the operating arm) should be on the other side. They are made from bits of tube, with the lower portion run back and forth over a piece of sandpaper on a spare piece of boiler tube; roughly drill the tube to the curve to fit onto the boiler with lots of small holes first then cut between the holes and clean up the then very rough edge, then it is time to sand the curve into the small piece of tube. The extreme top of the sand dome is from the top of a hemispherical topped machine screw, (clean it up before sawing it off), into the screwdriver slot goes a collection of a glass headed pin, with a couple of tiny pieces of plastic tube, all glued together and into the slot, the rest of the slot then being filled with filler and sanded smooth. Fit the whole thing onto a .5mm disc and it is then glued to the (5 layer) top.
A lot of the ideas I have used here are directly from the Mason Bogie MasterClass, - which is being produced by David Fletcher, I added the 'fiddling about' to make my own 'curly shaped' dome tops - that as a good bit of learning on the job, which I have wanted to 'try-out' for a quite a while.
The steam dome which is the rear one, has a series of plastic card strips fitted, one on top of the other, onto the pieces of plastic pipe to form the middle sections of the domes. These multiple strips will be made into the curved edges (sand them to a curve when dry, it will not need very much work with a rat tail file);on the top & bottom of the centre section. The sand dome has yet to have them fitted, there a 4 sets of strips for each set for the top & bottom.Looking at the 3/4 view I think the smokestack is tilted backwards a bit, or it may be the camera lens that produces the ean
The cab walls have been completed, the cab being made from multiple layers of 1mm plastic card. The 'masterclass' articles suggest 2mm thick pieces: I have found this thickness is the 'very devil' to cut - the best method is to laboriously use a jewelers saw, with tiny drilled holes marking the corners of the panels to be removed.Using 1mm thick is much easier, BUT you do have to ensure that all the layer(s) are very well glued together with plenty of adhesive, don't stint on it!I have also added a couple of armrests to the rearmost (which are open) windows, the roof will be done next. There is more on the cab later with some photos as well.
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