Half a year has slipped by since my last post on this blog! I remember those heady days, exploring the possibilities of my new Silhouette cutter, when a week between posts seemed a long time. This model has been a different challenge and there have also been many distractions, including a persistent virus infection through the so-called (very cold) Spring and then, more pleasantly, the arrival of a second grand-son.
I have always described myself as an 'impressionist' modeller, so venturing into Broad Gauge territory has been a culture shock. Most BG models are 'true scale' and built to precision standards, which have left me in awe of the engineering expertise displayed in most of the models I have viewed.
My own scratch-built 'standard gauge' models were very simple, based on a folded platform, which formed a solid base for the 'upperworks'. Broad-gauge engines need to be approached in a different way, since there is a lot of 'daylight' between the widely-spaced frames and everything can get very 'floppy', without suitable bracing. I learned all these things the hard way and came close to giving up on several occasions.
I also thought I had made a big mistake in adopting the Hornby wheels from 'Lord of the Isles', since these are over-size but do have the merit of the correct number of spokes (24). Despite turning these wheels down as far as possible, they remained over-size and, with a four-coupled chassis, the discrepancies mount up, in terms of overall length. When I compared the dimensions with the drawings, they seemed excessive but, when I overlaid a photo of my model over a side-on view of the prototype 'Coeur de Lion', I found. to my surprise. that the model seems to have captured the overall 'look' of the prototype rather well
Another aspect of my model that I found unsatisfactory was the excessive width of the splasher-tops, where I had erred on the side of caution when considering the clearances around the driving wheels. Their construction had been a very 'fiddly' task, so I did not relish the thought of taking them all to bits and starting again. Fortunately, I found it was quite easy to 'slim them down' with the aid of a sanding drum on my mini-drill, so another concern was averted.
In my last post, I described the need for some 'inside motion' to fill the yawning gap between the frames. Adding this also provided the means, through the motion plate, to add some necessary stiffening between the widely-spaced mainframes. In order to provide sufficient rigidity and alignment while fitting these inside components, I hit on the ideas of using temporary spacers at the axle locations, by means of long fixing bolts, with multiple nuts, to define the separation of the frames all along their length.
These temporary fixings allowed me to solder fixtures between the frames, including the footplate at the back-end and the motion plate, amidships, together with a substantial buffer beam and drag box at the two ends, all in good alignment with one another.
At last, I could see a way of mounting the boiler onto a suitably rigid chassis and so I decided that it was time to start to fit the 'cosmetic' overlays; now with reasonable confidence in achieving a satisfactory final outcome.
The firebox-boiler-smokebox assembly was all derived from the Broad Gauge Society kit for the Gooch Standard Goods. Overlays are provided in this kit for both the smokebox wrapper and the front face, including the smoke-box door, to show the various rivet lines. Rather than risk melting the main solder joints in the underlying structure, I decided to attach these overlays by means of superglue, after carefully cleaning all the mating surfaces, to ensure good adhesion. Most of this detailing went smoothly enough, except for the wrapper at the top of the smokebox, where the large hole for the funnel made it difficult to form a smooth curve, without the thin brass sheet developing a kink.
I think whoever designed the sand-boxes for the prototype engines must have been aiming to set a challenge for the builders! Not only do these boxes nestle against the curved splashers over the driving wheels but they also follow the curve of the footplate as it rises over the leading wheels.
I addressed this challenge by making the boxes 'origami-style', folding a small piece (14 mm x 12 mm) of brass sheet, marked with the curves around which the edges of the finished box need to fit. I then cut out the outlines using jewellers' snips.
Once folded, to make an open-backed 'box', I filled the inside cavity with modelling putty, to form a rigid structure. I then glued the box in position onto the curved footplate
Another small pair of components to be added are the inclined supports for the boiler, placed just ahead of the sand boxes. I glued thin strips of brass to the sloping edges of the motion plate, which I had already soldered between the frames.
So having come close to 'giving up' several times, I have completed all the major components. There are still several rods and levers to be attached and then it will be time to hide much of the brass-work under a layer of primer. On these early locomotives, however, there will still be quite a lot of brass 'on show', which will need regular polishing.
Hopefully, my next post will show something resembling a completed model