Following my previous post, where I showed how I made a cattle truck side, I have followed a rather convoluted route to arrive at a model of the complete body.
I could have printed a flat floor and some ends and then pieced all the parts together but I got caught up in the idea of trying to print the whole body in one go. I soon abandoned this idea, when I realised it was going to involve a lot of support structures for the various horizontal openings, but I did get as far as forming a body shell by the same method I have used previously for carriages.
Then, I had the idea of making the floor and ends as one ‘component’ and the roof as another, onto which I could fasten my already-printed sides. The selection of the various parts proceeded as shown in the following screen shots from my ‘Fusion 360’ software:
Step 1 shows how I extruded the body from a drawing of one end of the cattle wagon – the overall length is 66mm, corresponding to 16’ 6” in the prototype. In Step 2, I set a reference plane, offset by 25mm above the origin, and used the ‘split body’ tool to separate the roof. In Step 3, I drew a rectangle on the top of the main body and used ‘press-pull’ to open out the interior leaving just the floor and ends. Step 4 shows one of the body sides, which I described in the previous post.
I exported each of these separate body parts (floor + ends, sides, and roof) to my ‘Cura’ slicing software and used this to create the gcode print files, used by my E180 printer.
One advantage of making the components individually is that they print relatively quickly, since there is very little ‘depth’ in each component. Typical printing times were around 45 minutes for each component, so it was not too long to wait before I had all the parts for the body of my cattle wagon.
The next consideration was what glue should I use to assemble the model? The answer, as I discovered in a previous post was ‘none’. I set my temperature-controlled soldering iron to 200°C and used the tip to ‘weld’ the sides to the ends of the body. This is a very easy process because the plastic of the body has low thermal conductivity, so there is no danger of melting more than I intended. Also, it’s easy to hold the pieces in register while applying the soldering-iron tip, with no danger of burnt fingers. The bond is formed almost instantly and seemed very robust after a few moments of cooling.
First of all, I carefully aligned one of the side panels to one of the end walls, then used heat from the iron to weld the outer corner. Once this was secure, I ran the iron along the seam, to make a firm ‘welded’ joint. I fixed the other end of the side in the same manner and then continued by fixing the second side panel.
Of course, I could not fix the roof in the same way, as I have no access to the interior of the wagon once the roof is in place. I intend to use a hard-plastic adhesive but, as yet, the roof remains unfixed until I complete the painting.
After completing the body, I turned my attention to the chassis. I used a similar method of construction to that used earlier for Broad Gauge carriages. I printed the floor ‘upside down, with the axle boxes and springs built up by printing upwards from the floor. The design as developed in ‘Fusion 360’ and then 3D-printed from ‘Cura’, is shown below:
The next question was what livery to use. According to the Broad Gauge Society journal ‘Broadsheet no.6’ (1982), the earliest livery, as applied to an iron goods brake van in1852 was: "The whole of the van including the wheels, axles, axleboxes, side springs and every part … brown colour and figures as might be directed,". Similar specifications apply to other early wagons, so I assume from these specifications that ‘waggons’ and break vans were all-over brown in the 1850s.
The following photo shows the model in its current state, although I have altered the colour in Photoshop as I have not done any painting yet. During the 19th century, it was standard practice to lime-wash the interiors of cattle wagons, which led to extensive white stains on the outside as well, so I shall include these when painting the model.
My initial simple chassis design is insufficiently robust, so more work is needed. I only realised at a late stage that the cattle wagon is narrower (at 8' 6" wide) than the carriages I have built before and this left insufficient room for strong axleboxes. I need to investigate alternatives, which may need white metal boxes to achieve adequate strength. Once I have a suitable chassis design, I shall continue to the 'open-top' style of cattle wagon, to add some variety to my planned cattle train.