The Irish Railways 3d printing thread

[Rob R]

A bit more percieved wisdom picked up from various sources.

Print a groove around the outside of the rim and fit into the rim with a smear of epoxy.

Apparently some loctites can react to the 3dp plus shrinkage issues.

[Horsetan]

On 18/5/2026 at 2:13 PM, Northroader said:

Nice update, I did do some long time ago, so good to see how it’s done now. My main struggle seemed to be with keeping the mould flat and level whilst casting, then getting the cast part to have a uniform thickness after the pour.The catalyst for the rubber mix back then was also requiring a terrible level of care in its use, hope that’s improved? Certainly the results would be an easier thought process than mastering 3D printing.

Some people use LEGO bricks to form the moulding box

[Maitland]

Someday my prints will come... actually they did, 6 weeks late but 4 units rather than the 2 I ordered. It seems that Chinese industry isn't infallible - they order was lost in the system. Some takeaways here: first that they admitted it (not the Chinese stereotype about "losing face"), second they were tremendously helpful about making my initial STP file printable, thirdly that they rewarded me for waiting. Maybe the final STP was so good that their just-in-case extra prints all passed muster.

Now the prints themselves. I'm impressed by the detail they achieved, just standard resin. I was expecting the metalwork and bolthead detail to be worse. The strength of the units is acceptable- I haven't tested them to destruction, and my Pansy Potter niece who crushed a half - built 2mm scale brass 6 wheel carriage end to end 40 years ago- just to see how strong it was - is no longer available. She grew up to look like a supermodel and now lives in France most of the time. There's a little bowing in the ends, I can easily thicken them. 

The downside is that there are small excrescences here and there on the surface which are difficult to get off. They seem to be different on each unit, so I wonder if they are floaters in the resin rather than the remains of supports (I can't see where any supports were). You can see a couple on the louvres in the rather cruelly oversize (and badly painted) photo.

All in all, I'm reasonably impressed. They will be perfectly useable at £5 each, and are much better than I could scratchbuild myself. What do out Printmaestros think?

 

 

[Broithe]

12 minutes ago, Maitland said:

She grew up to look like a supermodel and now lives in France most of the time. There's a little bowing in the ends,

Harsh!

I'm sure her posture is better than most of us can manage.

The texture of the finish looks excellent for a wagon made from planks and a metal framework with decades of reapplied paint - almost like it's physically pre-weathered, just needing some suitable colouring now.

[Maitland]

That bad, is it? 

[Rob R]

4 hours ago, Maitland said:

That bad, is it? 

Your file is capable of a much sharper print.

I will fire up my resin printer tomorrow and have a go and do one on the FDM printer at 0.04mm layer height to get a comparison.

Don't get me wrong, your print is "OK" but I would have expected better from a commercial printer.

Rob

[jhb171achill]

6 hours ago, Maitland said:

Someday my prints will come... actually they did, 6 weeks late but 4 units rather than the 2 I ordered. It seems that Chinese industry isn't infallible - they order was lost in the system. Some takeaways here: first that they admitted it (not the Chinese stereotype about "losing face"), second they were tremendously helpful about making my initial STP file printable, thirdly that they rewarded me for waiting. Maybe the final STP was so good that their just-in-case extra prints all passed muster.

Now the prints themselves. I'm impressed by the detail they achieved, just standard resin. I was expecting the metalwork and bolthead detail to be worse. The strength of the units is acceptable- I haven't tested them to destruction, and my Pansy Potter niece who crushed a half - built 2mm scale brass 6 wheel carriage end to end 40 years ago- just to see how strong it was - is no longer available. She grew up to look like a supermodel and now lives in France most of the time. There's a little bowing in the ends, I can easily thicken them. 

The downside is that there are small excrescences here and there on the surface which are difficult to get off. They seem to be different on each unit, so I wonder if they are floaters in the resin rather than the remains of supports (I can't see where any supports were). You can see a couple on the louvres in the rather cruelly oversize (and badly painted) photo.

All in all, I'm reasonably impressed. They will be perfectly useable at £5 each, and are much better than I could scratchbuild myself. What do out Printmaestros think?

 

 

I must say, I like that!

[Maitland]

Looking though my graticuled goggling scope, I reckon it was printed at 45° in about 0.1 - 0.2mm layers. As I said, I don't expect the earth at that price, though a quicker turnaround would have been appreciated. Next, get my new Anycubic Mono 4 fired up (that was weeks late, too) and start wasting resin. It might be worth getting the latest update from Github if you're going to print it. But note I got the door handle hole spacing wrong...

I've learned a great deal from the process of designing the thing with 3D CAD, and getting it into a manufacturable state. The feedback from Seeed justified the cost in itself.

[Rob R]

Don't bother with the 45 deg lark.

Flat to the build plate, probably upside down so you don't need supports on the louvres.

A ring of medium supports to the deck with a smattering of heavy supports to make sure it stays put and then light supports on anything overhanging although most of it should be ok without.

I'll let you know how I get on at my end.

Have fun.

Rob

Edit. I am resisting the Sligo Tank (for now......)

Edited yesterday at 18:42 by Rob R
Edit

[Mayner]

Personally I think those wagon prints came out very well, you really captured the distinctive MGW ironwork especially hinges and door catches. Quality, pricing  & service consistent with the wagons I had printed for several years by a supplier in China.

I would not recommend printing models flat off the build plate without taking precautions to protect the printer LCD screen from resin spillage if the bottom of the resin vat ruptures.

I found out the hard way that printing flat off the plate/vertically increases the risk of rupturing/puncturing the film that forms the bottom of the vat resulting in cured resin forming on the printers LCD screen. 

Main lessons learned have been (a) Fit an LCD screen with protective film. https://store.anycubic.com/products/screen-protector and (b) Coat the PF film that forms the bottom of the resin vat with a PTFE based dry lube spray as recommended by Eoin ECM.

For rolling stock/detail parts I use a resin with abs/resilient properties to reduce brittleness compared to standard resins, recently been experimenting with (a cheap) water washable resin for buildings and structures, nice to work with but cured resin brittle even when compared to 'standard' resins.

[Maitland]

Thanks John, ordered the protective film and will call at Toolstation next time I'm passing. I'll put off printing till I've got them. Daughter and g-kids here for weekend so I've got plenty to do anyway. Dry lube spray to printing side of PF film or non- printing side?

Rob, don't do the small tank yet, having looked at supports I'm taking the chimney & dome off the boiler and making them separate components. Also I've decided my printed underframes are unlikely to work and looking at metal frames with turned spacers. That's part of my motivation for developing a one- off photoetch printer as mentioned in the etched kits thread, though it won't be done for this job. Traditional piercing saw and brute force I fear.

[Rob R]

First 4mm MGWR resin print.

Elegoo Mars 2 pro  using Elegoo water washable transclucent grey resin with a quick squirt if red primer.

[Mol_PMB]

Lovely! I'd be up for one of them if you would consider printing them for others.

 

'Slanjonok' over on RMweb has done a nice stl file for the British Railways plywood 'FM' insulated container, which could be seen in Ireland in the 1960s and give a splash of colour with their ice blue livery.

Pics below show one on a CIE lorry at Tralee (Kennelly Archive), and two as 'tail traffic' behind an AEC railcar on a Limerick-Waterford train (IRRS):

The .stl files attached are for N gauge so would need rescaling x2 for 4mm scale. There are two versions, for FDM and resin. 

I'm going to draw up the transfer artwork for them in the hope that I can get one printed.

 

BR_FM-type_Dia3-205_FDM_1-148.stl BR_FM-type_3-205_1-148.stl

[GSR 800]

1 hour ago, Rob R said:

First 4mm MGWR resin print.

Elegoo Mars 2 pro  using Elegoo water washable transclucent grey resin with a quick squirt if red primer.

Print looks very well indeed, I'd certainly consider one or two. What's the plan for the chassis?

[Maitland]

I was seeing how my prints turned out before designing the chassis. What I need to know is first, how flexible the material is for easing  axle ends into bearing cups, but rather more than that how to achieve a good 3 point suspension for 21mm/ P4.

 

BTW Rob that looks how I'd envisaged the thing. How long will it be before my printing's up to that?

Edited 3 hours ago by Maitland
forgot..

[Mol_PMB]

When I saw the body that Rob printed, my immediate thought was to use etched W-iron units with one wheelset rocking. 

The https://pregroupingrailways.com  Irish open wagons use 3D resin printed W-iron units which can be made to rock, and can be supplied for 21mm gauge. I found I had to remove some material to get them to work properly. Flexing them to get the axle ends into the bearings is possible, but I broke one (of eight) - I managed to glue it back together again. So it is possible but space restrictions behind the solebars and the strength needed for 3D printed parts may be an issue.