Further Adventures in Resin Casting: multi-piece CWs

See? Double ewes! (groan).

DB says: Well, seven CB coal wagons isn’t going to make a terribly impressive coal train is it? I suppose I could hang a few CWs off the back, just like they do on the real trains, and that might look groovy. After all, if Evan can make ugly diesels, then I can make ugly wagons...

So... I had a couple of small plastic squeeze bottles from the dollar store sitting on my workbench, which naturally had me thinking about those CWs again. I know it’s a leap, but stay with me on this one. Das Fettler provided some great detail pictures and a barely-visible plan of something that looked fairly similar to a CW: lo and behold, the curved hopper tub sides are a perfect match to the curvature of the bottles. As I had planned. Mwuahahaha.

After a few days of umming and ahh-ing about scratchbuilding three of four of these things I decided to cast them. And in hindsight, I’m glad that I did. In the previous casting posts, you may recall I made everything in one piece for simplicity, but because of the fine underframe detail and the deep tub-end angles of the CW, I decided to make these up out of separate 'side' and (somewhat simplistic) 'end' castings. Masters were completed thus (note the clear plastic section from the squeeze bottle cut and scribed):

And assembled into a mold box thus:

Rapid resin was used for the pours, as the bogies will sit under the end castings which should be strong enough to bear the load without bending. If the bogies were to sit further outboard on the thin end sections of the underframe, I would have used the strong slow-cure resin. Components began to roll of the production line, also thus:

I was pleasantly surprised by the quality of the castings. Firstly, there are zero visible air bubbles – one of the beauties of doing these ‘flat’ simple castings is that any air bubbles rise and sit on the backside of the castings (inside the model) where they can’t be seen. Secondly, that raised triangular end piece is quite deep, yet all those castings came out perfectly. I dripped the resin into that deep triangular section carefully, one drop on top of one drop at a time, letting the resin swim its way into the deepest recesses and expel air naturally. Pardon me. The only flaw in my master plan, if you'll pardon the pun, was that I used .010 x .020 plastic for the underframe rib detail, and this is really too fine - serious mold scrunching is required to get the resin in there and care is required when extracting castings to keep the detail from breaking off.

Gluing two sides to two ends was straightforward, as you might expect. End plates were added above the ends of the underframe, a bolster put in place and Microtrains bogies added. Two false floors were added – an unfancy one on the very bottom to hold some lead weight (keeping the centre of gravity low), and one near the top to support some coal. In the Midland Line video I have, I note that the odd one or two seems to have additional ribbing (for her comfort) along the undersides. Perhaps someone out there in the Blogstadia can tell me whether they have different rib layouts on different sides or whether there are two batches of wagons. I added extra plastic ribs to both sides of two wagons and left the other four with the minimal ribs as cast.

One of these days I'll attempt to restart the decal factory.

Now you might say that these aren't quite in the same league as the DFT as far as detail and accuracy (and even squareness) goes, but to my mind they don't have to be - the shape of the tubs and end angles says "CW" loudly enough for me. A few brake details and brakewheels should probably be added on top of the end plates but in all honesty, as these will be running at the back of an NZ120 coal train, I doubt I'll bother.

I doubt you'd hear that said out loud inside the big house at 9 Mill Street.

Not pretty, yet effective