Festiniog Railway Cleminson 6 wheel coal wagon

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Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Fri Jan 13, 2023 10:16 am

I have started yet another project - this time to see if I can create a model of this wagon to print on my resin printer. The challenge will be the small build area of the Photon Zero printer. I bought it with making figures in mind - but this is a large wagon.

So firstly the 3 D model drawn in shetchup:
Screenshot 2023-01-13 at 09.38.40.png
Screenshot 2023-01-13 at 09.38.40.png (305.12 KiB) Viewed 3416 times
and a view of the underside:
Screenshot 2023-01-13 at 09.39.16.png
Screenshot 2023-01-13 at 09.39.16.png (290.43 KiB) Viewed 3416 times
The model is based on the 7mm Association drawing of the wagon, a scan of which you can see in the background. I have tried to follow the Cleminson principle and have pivoted the outer wheel sets over their axles, and made the centre wheel set slide sideways. The three "bogies" are linked at each end with a pin which isn't shown in the view of the underside - to be made in brass later. You can see the slot and hole ready for it.

I have created a circular slot in the area where the outer "bogie" pivots, and a linear slit in the area where the centre "bogie" slides. These will accommodate stainless balls 2mm diameter, which should make the mechanism operate freely. The slots can be seen in this view:
Screenshot 2023-01-13 at 10.05.13.png
Screenshot 2023-01-13 at 10.05.13.png (184.86 KiB) Viewed 3416 times
The axle boxes will slide in the "W" irons and have small coil springs between the bogie and the axle box:
Screenshot 2023-01-13 at 10.05.58.png
Screenshot 2023-01-13 at 10.05.58.png (26.58 KiB) Viewed 3416 times
This is something I have done before on the model of Ffestiniog coach 16 which I am just finishing off. The springing actually works, not necessarily as per the real thing but even if we assume that the spring is fully compressed most of the time it has the effect of keeping the wheel in contact with the rail when the wheel encounters a dip in the track - so it does not risk derailment.


The main body of the wagon will have to be printed in 4 parts. The first was printed overnight, and the second is about to start. So a photo of the first section shortly.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Fri Jan 13, 2023 10:59 am

The first print:
IMG_2692.JPG
IMG_2692.JPG (1.87 MiB) Viewed 3409 times
It gives some idea of the size of the wagon compared to a slate wagon. Pity the slate wagon is in the forground but it shows the rivet detail better than the other photos I took.

The second part will be 8 hours printing.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by ge_rik » Fri Jan 13, 2023 3:49 pm

Looking forward to how it works. It took me a while of tweaking and fettling to get my Cleminson chassis to work reliably bit I've found it's worth it. I recently ran a mixed train which included one of my Southwold Cleminson coaches. For various reasons, I had to run the train backwards and forwards quite a few times over track which I hadn't fully cleared - so there was a fair bit of small debris between and sometimes on the rails. During this session, almost every item of stock (including the loco) became derailed at some point - EXCEPT for the Cleminson coach which remained resolutely on the rails.

Of course, now I've made that statement, I'll have nothing but trouble with it the next time I run it.

Rik
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Fri Jan 13, 2023 4:19 pm

ge_rik wrote: Fri Jan 13, 2023 3:49 pm Looking forward to how it works. It took me a while of tweaking and fettling to get my Cleminson chassis to work reliably bit I've found it's worth it. I recently ran a mixed train which included one of my Southwold Cleminson coaches. For various reasons, I had to run the train backwards and forwards quite a few times over track which I hadn't fully cleared - so there was a fair bit of small debris between and sometimes on the rails. During this session, almost every item of stock (including the loco) became derailed at some point - EXCEPT for the Cleminson coach which remained resolutely on the rails.

Of course, now I've made that statement, I'll have nothing but trouble with it the next time I run it.

Rik
I'm also looking forward to seeing how it runs. I suspect the spring suspension will help - the bogie coach (Ffestiniog coach 16) stays on the track well - so I have high expectations.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Wed Jan 18, 2023 8:14 pm

The main body is now printed and glued together:
IMG_2699.JPG
IMG_2699.JPG (1.4 MiB) Viewed 3275 times
The ends are currently in the printer.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Fri Jan 20, 2023 9:14 pm

I now have the main body printed and assembled:
IMG_2703.JPG
IMG_2703.JPG (1.57 MiB) Viewed 3243 times
This is a bit experimental in that I have never tried to make something which will have to take any force in this way before. You can see that I have included the buffers in the end prints. I don't know how that will last, and in particular I am sure that the loops for the couplings will break off the first time they have to take any load.

However it isn't that weak! For example you should be able to see in the next photo that the rings on the wagon sides are actually separate rings - and they are not extended to touch the body (which is what I have done before). This body has been subjected to some rough handling as I have been filling and filing the bottom where there were some faults - but I have not broken any of those loops in the process:
IMG_2704.JPG
IMG_2704.JPG (1.22 MiB) Viewed 3243 times
I have had some setbacks as well. So in the spirit of sharing my successes and my failures here is my first attempt at the underframe:
IMG_2705.JPG
IMG_2705.JPG (1.45 MiB) Viewed 3243 times
These components were printed with the buffer end to the platform - on end might be a better description - and both have at least partly parted from the supports holding them onto the bed. One more than the other, and that one is quite distorted. My first thoughts were to blame the resin, but on reflection and looking closely at what happened I think it was lack of supports.

So perhaps I should explain my thought process and the resins I have been using in the next post!

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Fri Jan 20, 2023 9:48 pm

Firstly resin. I have been using an "ABS like Resin" which I got from TechnologyOutlet.co.uk. I have mentioned it before - and it has not been listed on their website for a while. Having contacted them I now know that they have rebranded it and it is now called tough: https://technologyoutlet.co.uk/collecti ... sin-1000ml. The difference is that it is now £41 per litre - and I'm sure it wasn't that expensive before! As I have been printing this wagon I ran out of this resin - you can see some early components in the background of some of the photos (they are much whiter). I have tried a resin from the place I have been buying my filament from, polyprops.co.uk. They sell a clear resin and pigments to colour the clear resin, and the resin is reasonably priced. Seemed worth a try! So that is the current resin.

When the under frame failed my first reaction was to blame the new resin, but when I actually handled the cured part I could see that that wasn't necessarily correct. Apart from being distorted the component was stiff, resilient and strong. I have come away thinking that that buffer which I thought would break is in fact unlikely to break.

So we come to supports. When I was researching resin printing one of the videos I came across talked about the need to provide more support rather than less. The idea behind this was that it a print fails - usually because it didn't have enough support - then it meant emptying the tank or resin, cleaning hardened resin off the film on the bottom of the tank and putting it all back together again. Lots of mess and effort which could be avoided by deliberately adding too many supports. A successful print means you just refill the tank and print the next bit. I think I go along with that idea!

I also quickly learnt not to print anything flat - parallel to the tank bottom - because that made the component more likely to fail by sticking to the bottom of the tank rather than the build plate!

So I'm going to modify the underframe and reprint it. I can see that it can be thicker than the full size version, and that won't be visible. Instead of printing two at once (trying to save time) I am going to print one - and at an angle.

The beefed up under frame:
Screenshot 2023-01-20 at 21.40.52.png
Screenshot 2023-01-20 at 21.40.52.png (56.16 KiB) Viewed 3241 times
and how I intend to orientate it to print it:
Screenshot 2023-01-20 at 21.42.54.png
Screenshot 2023-01-20 at 21.42.54.png (71.66 KiB) Viewed 3241 times
I think this also shows you how close these compontnts I am making are to the maximum size I can print on this printer.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Sat Jan 21, 2023 6:04 am

I think I pretty much concur with all your points on this. Two things I would say though: (1) "More supports " are great but be careful not to get them into places that you can't get to to clean off the marks. (2) Some of yours look perilously close to vertical faces, with the big risk of them inadvertantly fusing together. That is exactly what happened when I followed very similar thoughts with my first big print, of a slate wagon.

https://gardenrails.org/forum/viewtopic ... on#p158615

Qu.: what support are using ( small, med, large?) and what contact with the model ( ie shape, diam, penetration?). This is something I've never quite got satisfied with myself - I usually end up with big ones even on small parts.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Sat Jan 21, 2023 1:48 pm

I think the best way I can answer your questions is to provide screen shots of the settings which I am using:
Screenshot 2023-01-21 at 13.43.30.png
Screenshot 2023-01-21 at 13.43.30.png (41.45 KiB) Viewed 3191 times
Screenshot 2023-01-21 at 13.43.17.png
Screenshot 2023-01-21 at 13.43.17.png (53.38 KiB) Viewed 3191 times
Screenshot 2023-01-21 at 13.43.08.png
Screenshot 2023-01-21 at 13.43.08.png (50.32 KiB) Viewed 3191 times
Screenshot 2023-01-21 at 13.42.55.png
Screenshot 2023-01-21 at 13.42.55.png (62.58 KiB) Viewed 3191 times
Not that there is anything more than chance as to what I might have altered from default!

I usually leave the supports set to medium.

I will keep an eye out for supports which might stick to the surface - not a problem I have experienced yet.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Sat Jan 21, 2023 2:02 pm

Thanks for that Trevor. I'll sit down and compare with mine when I get a sec.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by SimonWood » Sun Jan 22, 2023 9:47 am

Thanks Trevor and Philip for this discussion about resin printing and slicing techniques, every line here is illuminating: these are exactly the details I’m going to need to get my head around. For reason a bit too involved to go into here I haven’t had a chance to do more than make a test print on my printer yet, but hope to make further progress soon and what I need to figure out now is exactly this detail of how angles and supports differ when slicing for resin rather than filament….

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Sun Jan 22, 2023 11:23 am

Simon,
This quite a good general article on the subject of angles and supports. It also get mathematical at one point so it might be up your street! :lol: I haven't looked into the subsidiary video it links to, yet ( keep meaning to, but... so might try it now)
https://3dprinterly.com/how-do-you-orie ... -printing/

Thing is to forget all you've learned about fdm supports, resin is a very different animal.

I was actually considering dropping you a line to ask how you are getting on with your Whale 2, but I guess you've answered that for now. I may be in the market for a bigger resin m/c but that one doesn't seem to be available anywhere except Oz now, and that one is heavily discounted, so I'm guessing it is now out of production and your cheap price back in Nov was effectively an end-of-line sale price.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Sun Jan 22, 2023 11:42 am

That is also an interesting reply!

I have been thinking about a larger resin printer. I suppose what I bought was an end of the line offer at the time.

There isn't anything wrong with what I have - it worked as a trial to see how resin printing worked - but now I want something with a bigger build area, and perhaps something more advanced.

For example when it won't work I would like some sort of message to tell me why. It is too hot or too cold or is it faulty?

So any thoughts on a replacement machine are of interest.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Sun Jan 22, 2023 1:34 pm

Trevor Thompson wrote: Sun Jan 22, 2023 11:42 am now I want something with a bigger build area, and perhaps something more advanced.

For example when it won't work I would like some sort of message to tell me why. It is too hot or too cold or is it faulty?
I know that recent machines do come with wifi connectivity, which is my own 'must have', and I've also seen m/c's with an automatic resin top up facility, although I can't imagine I'd ever need that, myself.

Ambient temperature isn't a problem for me since mine are indoors. I know you have found it to be a problem, but I'm not sure it is a widespread enough problem for a manufacturer to build the sensor and programming into the printer? Wouldn't some sort of thermostat, set to the top and bottom temperatures and linked to a bell/flashing light/whatever, be just as useful and much simpler?
Trevor Thompson wrote: Sun Jan 22, 2023 11:42 am So any thoughts on a replacement machine are of interest.
Yes, indeed.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Sun Jan 22, 2023 2:06 pm

The under frame printed out OK. So this is how it printed:
IMG_2711.JPG
IMG_2711.JPG (1.46 MiB) Viewed 3129 times
and after a bit of judicious filing, in place under the wagon:
IMG_2712.JPG
IMG_2712.JPG (1.22 MiB) Viewed 3129 times
The other half of the under frame is printing. My workshop is currently nice and warm - the wood burner is lit!

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Sat Jan 28, 2023 8:31 pm

Both parts of the under frame is now printed and fitted. The three "bogies" are also printed and roughly in place on the under frame:
IMG_2718.JPG
IMG_2718.JPG (1.85 MiB) Viewed 3262 times
The central one had ball bearings under it and it slides sideways nicely. The end bogies await their pivot blocks, but basically these parts all fit as intended. You can see that the central bogie is as far away from you as it will go, and the other bogies have rotated roughly where you would expect them to get to even though nothing is fixed down yet. Some filing was required to get proper fits - and you can see the dust from that. The wheels are printed, and the axle boxes are in the printer at the moment.

Things went a bit wrong then I added the black pigment to the resin bath - I added too much and the prints failed. Having watered it down with more clear resin we are printing again - hence the black bogies. The idea is to print the black components black and avoid having to paint them.

More to report shortly.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Sun Jan 29, 2023 7:11 am

I've found problems with black resin, even when bought as black. Sometimes its fine and sometimes it just fails. I think it may be to do with not shaking it up enough in the bottle, and also leaving resin in the vat allows the pigment to settle out, which it does quite noticeably over time.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Trevor Thompson » Sun Jan 29, 2023 11:00 pm

philipy wrote: Sun Jan 29, 2023 7:11 am I've found problems with black resin, even when bought as black. Sometimes its fine and sometimes it just fails. I think it may be to do with not shaking it up enough in the bottle, and also leaving resin in the vat allows the pigment to settle out, which it does quite noticeably over time.
Yes I am also having problems with it. Lots of failures of things I have printed out successfully in the past with different resin.

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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by philipy » Mon Jan 30, 2023 8:08 am

Trevor Thompson wrote: Sun Jan 29, 2023 11:00 pm Lots of failures of things I have printed out successfully in the past with different resin.
Yes, that as well.
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Re: Festiniog Railway Cleminson 6 wheel coal wagon

Post by Phil.P » Tue Jan 31, 2023 10:34 am

I would think that you would have to increase exposure-times / power, and curing would also take longer, for 'black' items? - I assume 'black' resin is more opaque, than others?

Or am I being naive?
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