Maitland

I'm getting beyond frustrated. You're all producing wonderful crisp prints and all I'm producing is rejects. Latest try, the print didn't stick to the plate. Twice. Obviously something I'm doing wrong- Anycubic Mono 4, standard resin, level it according to instructions (repeatedly), make sure the FEP is clean, the designs appear to be printable, at least Photon Workshop doesn't object. Use their recommendations for exposure, I don't know any better. Where from here?

So, let's get some figures: what kind of shrinkage - from design to print, and from production to X years later - can we expect, with different resins? Is it environmentally (temperature, humidity, time etc) sensitive? Does it depend on part size? For example, if it's the same for all parts with the same resin, printing chassis and coupling rods would be fine - the centres will just track each other. If there's a small but significant difference, "loose" crankpin holes, with actual coupling by gears, would compensate. Thinking here is, for the home printer, printing a new chassis every "x" years might be tolerable.

Printed chassis uses a similar motor/ gearbox as I got for the Sligo tank. Almost free (about £6) from AliExpress. There's also a slightly more "expensive" version with a 12V coreless motor. You can get them in various gear ratios, and single straight like this one, or double 90° shaft. That valve gear looks awfully frail though.

Recognised the (fighting) tank straight away, but couldn't remember the name. Whippet. As a matter of interest, what CAD program are modellers here using? I'm using Solid Edge. It's clunky and viciously complicated, it drives me nuts and it's going to send me to hell for bad language. And you have to update every 3 years or it stops working. But when it works it's accurate and the results seem pretty good. I've tried Freecad 0.xx - utterly hopeless - and 1.1 - less hopeless but hard to use, and the tutorials and documentation are very out of date. So what are the alternatives, good and bad points?

That looks nice.. now tell us how you print it..

Well, that's given me a lot to chew over. I've printed it out, and will be perusing it carefully. I must say, the matter of support is one of my biggest concerns at the moment. That and Madame's complaints about the smell...

The drooping on the tank happened after I'd left it supported only by the buffer beams for a week or so. I've added a structural longitudinal support to the underside of the running plate, between the frames, but do I need a longer post- cure? The strips are all well and good for vans etc where it's all outline, but I see your van has a floor.. how does that get supported? As I've said, I'm very new to this business, and so far I've allowed the Anycubic program (as we used to call apps) to generate supports. It generates far more of them, pretty randomly. It supports, for example, the external framing. I don't know what I can get away with. I also note your brake gear and stays between the W irons etc.. it looks very flimsy, does it last? What about things like lamp brackets, smokebox door handles, grab rails?

Must apologise about slow progress on Sligo tank. Long Lapland (Sapmi) trip, folk festival, grandboy minding and suchlike commitments have kept me away. Plus the fact that when I do work on it, I keep changing my mind. I'm looking to do the cab, tanks and running plate all as one now. So here's a screenshot from Photonic Workshop just to encourage me to get going properly again. Of course I don't plan to print it like that, it's just to check that the bits actually fit together. They don't, a bit of tweaking to do.

Sorry about my lack of understanding, but I can't see what this has to do with Terry McDermot?

I used automatically generated supports from Photon Workshop, don't understand enough to do my own yet! Some obviously silly supports were edited out. The supports inside the tanks and those inside the splashers were a right b*** to get out.

Close, but no cigar... Apart from the hole in the bunker back, which is my fault (I dropped it while releasing it from the build plate) the faults are: the flaws in one side of the tank - it curves slightly at the front corner. The location tab under the cab door failed to print on one side the buffer beams have that "interesting" curvature on the bottom edge - it's supposed to be straight. The deck isn't rigid enough - it droops. The location tab serves the secondary purpose of making the cab itself a bit more rigid instead of depending on the thin connection over the door, so I'll make it into a flat plate recessed into the floor. Per ordure ad astra.. -

Semis were what we called Stanier Duchess class 4-6-2s back when I was the little boy watching the big kids with ABC books tick off the namers. I never did really understand train spotting.

And that's true, but look back at the 50s and 60s and 70s, and Great Britain.. well, mostly, England and Wales. There were a lot of young, energetic, motivated people, with just enough backing, through mum and dad, the University grants, and a fairly lax social security system, to spend serious amounts of time doing stuff they wanted to do. This was the age of canal restorations, Talyllyn, Festiniog (before the f's proliferated), Bluebell, but particularly stuff like the Stratford Ccanal and Stratford Avon "restorations" that used methods impossible today. When a government realises that you can pay young and hopeless people to gain faith in themselves and marketable skills, at the same time as creating community facilities that create a positive feedback loop that keep that sort of thing going, the heritage thing becomes sort of obvious. Until then we're in the hands of small- shop grocer economics for the plebs, and wow-look-at-that untouchability for the superstars. Back in the 70s Ireland was full of idealistic backpackers- I was one- they will have told their kids in English, French, Dutch, German perhaps about wonderful quirky Ireland, that's where to start from to get their grandkids on a train singing "are you right there Michael". I've no solutions, but I think the idea of generating infrastructure by using otherwise unused talent - unemployed kids, hey, what about refugees- is worth thinking about.

Looks to me like the Hornby van has a single radius arc, but your van seems to have a multi- centre or elliptical end. You might have to empty several beer cans to make sure you get one that's properly emptied. Real ale or cheap Rioja man myself.... Oh and by the way I worked out why the ironwork was missing on the van. It's a long story, but essentially I used the wrong stl that didn't have it on. Version control?

At least I know what I'm aiming for. I'll thicken that whole side up. Sacrifices some of where I thought electronics might go though.