The Great Bear

That is what apparently is called a knot of toads...

Would that be the gray plastic primer or the yellow filler primer? I have tried this but my results were rather hit and miss. Ought to try again with more care. I have a few more samples ordered with design on both sides so double the stuff to practise on.

Thank you. The thickness is as you say restricted by the materials, the ones above were thickened slightly to work with the resin; with the nylon they could be a little bit thinner. The toplight body shape makes it harder, the paneling (and the droplights for that matter) eat into the sides and the thickness of the walls at the non-door windows is then exaggerated by the bollections. Below are some shots of another test sample, painted more neatly, including using a burgundy porcelain marker pen for the droplights and bollections - whilst not perfect the results are better than my hand painting. The material was SLS nylon polished but with some design changes: adding blobs for the door stops and hande, exaggerating the louvres on the door vents (so now just about visible a tad more perhaps needed) and a punt at adding the "commode" door handles. The latter I think I will drop - whilst not a disaster, they are over-scale of necessity and by the time you've painted them you might as well add the brass parts available from Comet or Roxey mouldings, especially if pilot holes for these are in the model shell. Also the moulded handles smack of Railroad Hornby! On the bottom left of this you can see the panel recess eating into the wall thickness. I reckon I can reduce the depth of the recess for that a bit. Heading in the right direction, but more experimentation needed. Thanks for the interest shown Jon

Good point, that is dawning on me as my experiments with my own 3d printed designs let down by my ham fisted painting. I'll get better with practise I hope.

Having been distracted by my attempt at making a toplight using 3d printing, I have finally got the A7 autotrailer finished. So the painting, lining and transfers aren't as neat as they could be but I am pleased with the result, something different from the standard Hornby model and accurate for the prototype (Kidlington and Woodstock branch) in my chosen post war period. Thanks again to Rue_d_etropal (Simon Dawson) for the 3d printed model. All the best Jon

Painted samples: SLS Nylon: SLS Nylon polished iMaterialise standard resin These photos are rather cruel close ups. My rubbish painting rather levels things, whilst the resin is still the best my painting has softened some details, whereas on the other ones to an extent it hides blemishes. Given my painting limitations I am not sure how representative of other's experience with materials?

Pictures of the samples with a single coat of grey paint (by hand): SLA Nylon raw SLS Nylon factory polished iMaterialise Standard Resin: The single coat of acrylic primer does not cover the resin material well, not helped by my application no doubt! It does show a pattern from the printing.

No, the finish was consistent

So here's a couple photos of the finished coach: The camera rather cruely shows off my poor painting! In additiion to the 3d printed bits the following other parts were used: Bogies - 3d printed 8" American by Stafford Road Model Works on Shapeways https://www.shapeways.com/shops/stafford_road_model_works?section=00+GWR+Churchward+Bogies&s=0 Wheels - Alan Gibson Coach door handrails - Roxey Mouldings Coach gangway, v-hangers (relaced the 3d printed ones), buffers, shell ventilators and probably some other bits I've forgotten - Comet models Various bits of plasticard/strip for roof rainwater strips, door hinges, end steps Things to improve/lessons from this first go: Increase separation of parts when putting inside one other, so don't get welded together (the mess up with the interior) Glazing, use thicker plastic and a lot less glue Add blobs for door handles, door stops, hinges - subsequent prints have had these Increase/emphasise some details eg louvres on door vents, roof rainwater strips so print Cast pilot holes in 3d printed bits for door handrails, buffers Increase thickness of floor on undeframe - bit too bendy Improve how body affixed to underdrame - didn't think about this when designing More care when sanding and/or get polished finished to ease amount required Painting of droplights and bollections - will try a paint pen Painting generally! Any other thoughts/suggestions welcome. All a learning exercise not just the 3d design and printing but in general modelling, so the next one should be better! All the best Jon

Yes I had to beef up the walls a bit to get this through the checks. Another downside, well adds to the expense of resin is that as part of the printing process support structures are added which then are cut away afterward. What this means is that you can't nest items inside each other, whereas say for the SLS nylon or MJF you can do this so the coach interior could be printed inside the body (just I didn't leave enough gap, next time better!) which saves on the cost.

Before having another go at printing a coach design I'm doing a little test, comparing different printing matetrials on a section of Toplight body shell, similar to that done on the coach as above - though some aspects changed, recess of paneling increased (to allow for some detail losss with my heavy handed painting and finsihing) Running through the samples in order of ascending cost 1st up is SLS nylon in this case from Sculpteo Next, SLS nylon polished from Scultpteo The photo does not show it so well but it does feel quite a bit smoother than the raw version Dyed HP multijet fusion, from iMaterialise Disappointing. In theory this should be better detailed than the SLS ones, but this print isn't eg lines for the door aren't showing. Maybe that was the dye? The C30 coach I am working on was printed in this material but by Sculpteo and not dyed and was better. Finally, iMaterialise standard resin Clearly, this is the most detailed print, you can see the detail on the door ventilator bonnets lost on the other ones. All together From left: SLS nylon raw, SLS nylon polished, Dyed HP multijet fusion, iMaterialise standard resin The resin costs around 1.6 x the cost of the basic SLS nylon. Whilst it is more detailed I am not sure that it is worth it for a coach as aside from the ventilator there isn't a lot of fine detail and tweaking the design might bring some of that to the other materials by exaggerating things. Right now, my preference is toward the polished SLS nylon as for a few quid more it seems a better finish, saving a bit of work. All may change when I paint these - that's tomorrow evening's exercise! All the best Jon

I'd sleep contentedly having done that, they look really good. Admirable stuff, making your coaches from scratch. All the best Jon

Nice work with the autocoach. I have the bits to do the same, though now down the list of priorites having scratch built another autocoach. Useful to see what the bits look like nonetheless. All the best Jon

Thanks, Mike. I expect you are right, the underframe as done was a bit rushed, something to sit the body on and see if the details like the v-hangers would print.

Thanks, Rich. I didn't print this myself, I got this done by Sculpteo (similar to Shapeways), one of the big on-line printing services. If you look in the thread I linked to you'll see that the 3d print did the raised detail and paneling pretty well. Some details are slightly enlarged to print, but I'm still trying to understand what can be done. My main issue is painting the droplights and bollections neatly. On the autotrailer, I cheated and used a separate thin patch of plasticard in front of the glazing cut to the droplight shape and pre-painted maroon. With the body side panelling I lost some of the detail as the the material used (and similar others) gives a slightly rough texture and I sanded it down a bit too heavily. Yes there was issue with masking. Thanks for the advice on masking, I do use Tamiya tape and generally find it good. What has complicated things is the join being at the point of the beading above the mid-rift panels so a bit of touching up in order. I did leave it on quite a while IIRC. The paints used are railmatch acrylics - from my experience on the autotrailer this seemed to to work best with the 3d printed material for me. This was on top of grey primer, but I sprayed that on too heavily. So more care generally is order, really. With this and the autotrailer as I've added more detail it's started to come together better so fingers crossed. Thanks again Jon

Thanks, Simon. Another evening or two and the autocoach will be done, will keep you posted. Yes, I must admit so far I'm inclined back toward doing stuff in SLS nylon; with a bit of tweaking, selective thickening and oversizing of details here and there, the design I had done would do for that and it is quite a bit cheaper. From what I've seen to date both iMaterialise and Sculpteo do seem a fair bit cheaper with their SLS nylon than Shapeways WSF. Having just dived in to the first project to see what can be done, I am doing some more structured testing of different materials/services and design iteration. I am awaiting some prints and will post my comparison in due course. I will be interested to hear your views. I will give just using acrylic paints by hand a go. I can't help but feel I made things worse with the spray paint, which matches your experience. All the best Jon

The autotrailer is coming along steadily, nearly there. I've been distracted having fun playing with cad and 3d printing trying to produce coaches. Here's the current state of progress on my first attempt, a C30 Toplight. My painting makes the model look worse than it would otherwise be. The droplights are bad enough but the bollections are worse and I think look too heavy on here. Any tips as to how to paint neatly welcomed! Skill and patience I need to acquire. I have some pens on order which might just do the trick instead. Otherwise everything will be in wartime all-brown More details on the coach and printing can be found http://www.rmweb.co.uk/community/index.php?/topic/130385-3d-printed-gwr-coaches-1st-try-a-toplight-c30/ All the best Jon

Through my work I an familiar with 2d Autocad so the 2d elevation for the coach sides using drawings in books I could knock together pretty quickly. The 3d stuff I picked up fairly quickly, a bit of trial and error to work out how to extrude objects and do complex shapes like the panelling on curved surfaces like the lower coach sides. As I said I have access to full blown Autocad so stuck with what I know. There are free alternatives out there like Sketchup and Fusion 360 that are likely easier to pick up and do just as good a job - best look at other threads here and ask others. Good luck with it Jon

Here's the current state of the coach, body painted (not that well, the droplights and in particular the bollections are a right pain), grab handles added and bits of styrene strip added on for the hinges (as they didn't print), the door handle and the door stops. Some of this I'll try and get to print in the next version to be printed. So far it's going ok I think, well enough to keep trying. I don't think my painting has done the model any favours, oh well, practice makes perfect. Thanks for looking Jon

Here's a close up of the 3d printed coach: The panelling detail including the bollections seems pretty good. Some details haven't come through for being too small, the door hinges and detail on the vents above the doors. The finish as you can see is slightly rough, perhaps a little less than Shapeways WSF but clearly needing some work. One thing I did mess up on was putting the interior inside the body. I didn't leave enough space between the two parts so they were welded together. I had thought I'd ruined the whole thing at this point but decided to do my best to fix things and carry on. So some demolition work with a dremmel was needed to cut this out, cutting the roof and end walls to get this out and then glue the model back together, the ends coming off worst. The result after a lot of glue wasn't particularly neat but painting can cover this. Similar to the autocoach to a spray with Halfords filler primer and some sanding got the surface to a better state: Compared to the Shapeways WSF material my impression was this needed a bit less work. I was perhaps too expedient using the dremmel for some bits of the sanding taking away maybe too much detail. One to learn! Following this a spray with grey primer got me to this: Looking at the photo now, it's clear in my haste I was too heavy with this spray and combined with some excess in the sanding a tad too much detail has been lost. All a learning exercise! So, at this point the body was ready for painting...

Having teased you with the images of the computer model, onto the realisation of it... As I said I am new to 3d printing, so what follows is just my observations so far. There seem to be 3 main providers of online 3d printing services: Shapeways iMaterialise Sculpteo (happy for anyone to suggest alternatives!) The default material offered seems to be nylon using the Selective Laser Sintering (SLS). This is what Shapeways term their White Strong and Flexible (WSF) material and the other two offer similar. The Autocoach I mentioned earlier used Shapeways WSF. A relatively new technique is HP mutlijet fusion which is similar to SLS but offers thinner parts and allows smaller details. It is more expensive than SLS nylon. Some sites offer resin or other materials as well but again these are more expensive. All the three sites provide tools for reviewing models to see if parts are too thin, whether it can be printed. I found the Sculpteo tool the best, easy to compare different materials. For example the shots below the model of the coach in their SLS nylon material and then their HP multijet material. You can see that the mutlijet material is more forgiving of finer details but is around 1/3 more expensive (compared to the economy/slower production SLS). The above showed that my design (after some iteration) was ok with the multijet material but some areas too fine for the SLS nylon. So, wanting to get something printed to see if the concept worked at all, I went for the more expensive multijet material. Two models were printed: The coach body with the interior nested inside it (to save on printing costs) - both the SLS and multijet techniques allow this, some others don't The underframe Results after my dinner...

Thank you. Yes, you're right about the waist pannelling and I've updated this in the drawing I am working on at the moment. It should look more like one continuous semi circle I think? If I can get this to work reasonably well then other coach types and styles like Concertinas I itend to do. In particular composites (non-brake) are a gap in what I have in my stock collection, the Hornby Colletts being all I have that is remotely accurate. The WS Beckett book on train formations shows several 70' composites on trains in my area of interest.

Having bought a 3d printed autocoach by Rue_d_etropal (see my layout thread http://www.rmweb.co.uk/community/index.php?/topic/26456-marlingford-begbrooke-making-a-diagram-a7-autotrailer/?p=2973057) this sparked my interest in this technology and its potential use to create rolling stock. My particular interest is the Great Western and whilst the recent Hornby Colletts have filled a huge gap in the RTR offerings there are lots of other types, especially older ones, not available in RTR and not available or easily available in kit form (eg Slaters Toplights). So, with a modicum of cad skills, access to the software and some armchair modelling time to learn 3d modelling in Autocad over Christmas I thought I'd this a give this a go, drawing up a coach in Autocad then printing using one of the online printing services. As a start and to give the technology a tough challenge I thought I'd start with a fully panelled GWR toplight - on the basis that if I and it can do this acceptably other ones will be fine. The chosen protoptype was a Toplight C30. I can't quite remember why I chose a 56' one not a 57', think it was the first one in Russell I came to! Rather than a scienfitic test things, do a little bit a approach, I thought I'd just dive in. So here's some 3d views of the model. (The underframe is a separate model and printed as such but I temporarily combined things for these shots.) I am not aiming for 100% fidelity to the prototype, but if I can get fairly close to the Slaters kits mentioned I'd be well pleased. If there are any great howlers in my interpretation of the prototype do let me know, but be gentle, please - my knowledge of coaches and details is limited, but as always I am keen to learn Some things l beefed up a bit trying to interpret the guidelines of the various printing sites regarding minimum thicknesses and detail sizes. The above shots I'm aware miss some details, things I perhaps could have added but was impatient eg dymano, door stops. Also in other areas I put detail which might not print. All just a test. I have had this back and have been working on it. More details later on...in the meantime, hope you find of interest! All the best Jon

Well done. That and the other volumes (to slightly lesser extent vol 3) are IMHO essential reading for any GWR modeller, not just of branch lines, if fidelity to a real prototype or plausible fiction and a detailed model are a priority. (Unless you happen to be the Stationmaster or similar and have encloypedic knowledge of all things western.) Enjoy your reading.

Well, in comparison, the class 800 hasn't claimed the life of an MP yet.