Readers with long memories may recall that, back in March 2017, I started to think about construction of a Waverley Class locomotive – ‘Rob Roy’. This was a part of a project to build the components of the two trains involved in the Bullo Pill accident of 1868.
My modelling of ‘Rob Roy’ became a test bed for many different ideas – how to build sandwich frames, adapting a brass kit intended for a Goods engine, exploring the working of early valve gears, and so on. In between, I was easily distracted into simpler tasks, such as building Broad Gauge (BG) carriages.
GWR Mail Train 1868
Then, in early 2019, a revolution hit my modelling world, as I struggled to get to grips with the use of computer-aided design and 3D-modelling. This spurred its own series of experimental projects, including making a model of a Gooch Goods engine ‘Tantalus’, using a mix of traditional brass construction with 3D-modelled parts.
Through all this, ‘Rob Roy’ has taken a back seat, partly because I was otherwise occupied and partly because the main outlines were complete. The fiddly job of adding the small bits and pieces (those bits that are crucial to a ‘good’ model) is all to easy to keep putting off!
I have also considered the thorny question of ‘colour’ in BG engines. The general opinion is that the colour was ‘Holly Blue’ and it was also referred to as Dark Blue-Green. Early copper-based blue pigments, such as Malachite, tended to have a bluish tinge and I began to speculate whether the early GWR colour was actually more like that later used (or continued) by the Wolverhampton works, when Swindon changed to Chrome Green.
I had already used Rustoleum ‘Painter’s Touch’ Dark Green paint for a Wolverhampton locomotive model but it seemed rather light to match the BG descriptions. For ‘Rob Roy’ I decided to try this paint again but with added black pigment to darken the colour. Whereas the original, lighter colour looked distinctly blue (to my eyes), it seemed to look ‘greener’ as I darkened the mix.
I find the result very satisfying and, for some reason, I find myself believing that this is a very appropriate colour for that period. It has a ‘distinguished’ appearance and sets off the brass-work very well. Others are, of course, entitled to disagree, as reliable evidence is lacking.
One thing leads to another and, once I had applied a couple of coats of paint, I began to think about how to deal with the awkward rounded ‘fillet’ between the firebox and the boiler. This is always a problem when building etched brass kits but I had side-stepped the issue with my model of the Gooch Goods ‘Tantalus’ by 3D-printing the firebox, with the fillet included in the Computer design.
Then I thought, why not simply extract the curved front of the firebox from the Goods engine model and print it as a separate component? The dimensions were already correct since ‘Tantalus’ and ‘Rob Roy’ used the same type of boiler. I ‘sliced’ the front of the firebox in my computer modelling tool, ‘Fusion 360’ and also cut the resulting ring just below the mid-point of the boiler to leave a horseshoe shape that would clip around and hold itself to the boiler, intermediately in front of the firebox. Once 3D-printed, I applied a coat of ‘gold’ paint and clipped the fillet into position on the engine. In my opinion, it looks good and solves an awkward construction problem.
3D-printed Boiler Fillet
After that, I decided to apply 3D-printing to those strange inverted springs between the two leading wheels of ‘Rob Roy’ Although my computer model looked quite good, the detail of the springs was too fine to be rendered accurately by my printer but I think they are adequate for 4mm scale.
3D Printed Spring
As my title indicated, this has been an ‘odds and ends’ post but it got me working on some of the finishing stages of ‘Rob Roy’ There are still many minor items to add, such as buffers, whistles, handrails and the like but I already have the necessary parts to hand and the same additions are required for ‘Tantalus’, so I will tackle them on a ‘production line’ basis