The Irish Railways 3d printing thread

[Rob R]

I am starting this thread to act as a repository for 3dp questions, answers, project updates etc. that are Irish Railway related.

Open to all, not just for me.

 

First off, with the 7 ton MGWR update elsewhere, a couple of photos of the latest FDM printed MGWR open wagon.

4mm and S scale.

A bit more work needed yet but we are not too far off.

Edited Thursday at 10:40 by Rob R

[Rob R]

Got bored playing with wagons

From a Recreation 21 file to be found on Cults 3d.

It's not the best but useful as a test to see what can, and cannot, be done.

[Rob R]

8 and a half hours later.

The eagle eyed amongst you wiĺl have noted that I broke the chimney and the cab steps while getting the supports off.

No great loss as they were going anyway along with the splashers - far too close together.

Ok for a first attempt, might have another go at 0.4 layer height but this was just a "quick" test because I really wanted one of the railmotor versions. Probably heading for 15 hours with the smaller layer height.

Not sure what is going on with the cab side and end either. More playing needed.

Good fun.

Edited Thursday at 16:36 by Rob R

[commerlad]

I'm still astounded by the fact that people try to print everything in 1. Yes I know it can but,

Don't bother with the cab roof, A cut up Coke can still works, It's thinner and no layering detail.

Think of a kit , The Cab Sides and Back and the Tank Side's would all be better if each part was printed Horizontally. (Other than Rivet detail its all 1 layer) So nothing to smooth.

Also if it's in bits it is easier to paint.

[Rob R]

I know, but that is how the file came and it is too big to stick into my usual cad program to chop it up.

Was only playing to test the limits of the machine anyway.

Would also really need to print things in PETG 'cos you can stick that with MEK.

Edited Thursday at 17:39 by Rob R

[Colonel]

Interesting, so great idea to start this thread. A few of us will need to learn some new terms like PETG, but that's all part of something new.

 The photos certainly show some issues, with what seems like a lot of bits to remove. All those rivets would be a pain to do in etched brass, though how you'd keep them while cleaning up the print lines is another matter - all part of the testing I guess.

 While there's very little I've seen so far (louvres excepted), that I can't do via traditional methods, that doesn't mean I'm not interested because it is how the hobby will develop, so keep it coming. Indeed, with some traditional fittings formerly done via whitemetal casting, such as axle boxes, chimneys, domes, valves and so on, this is certainly where printing can take over.

 Years ago, remember Dick Bolland, of Shedmaster Models, telling Laurie Griffin that such castings were where there was money to be made, rather than whole kits. Laurie eventually took on Dick's stuff when he started Laurie Griffin Miniatures, so there must still be some truth in the story today.

 

[Rob R]

I should be printing stuff for the SSMRS stand at Railex but I have been distracted again.

Broken window pillar was ham fisted me getting the supports of.

Never mind, it was only a quick trial print.

SLNCR Railcar B if you were wondering.....

The test print, from a Recreation 21 file, has done it's job.

Looks nothing like the real thing so I won't bother with the 18 hour print for the rest of it.

Edited Friday at 20:07 by Rob R

[Colonel]

Interesting - though following Mayner's post, don't think I'll be chasing a 3D printer any time soon.

 Very much admire the pioneering work going on, but if anyone is interested in a halfway house towards small scale mass production, resin castings can be very good. Have made numerous wagons, coaches and coach seats this way. First you make a master, from plasticard -  usually a side and end of the wagon/coach. Next you make a mould of that. This takes 24 hours to cure, but after that, using 2 part casting resin, each part only takes 45 minutes to set.

 Different skills, but overall found I could create the parts for 3-6 wagons in far less time than it sounds like doing the art work, de-bugging and printing would take.

[Colonel]

 Further to this morning's post, here are some photos of the basics of resin casting.

 First the 'stuff': below is what you need to make the mould - a tin of 'goo' and the setting agent/catalyst. One part of the latter to 20 parts of the former. Mix and wait 24 hours for it to set.

 The other stuff is the resin - two parts mixed equally, which take well under an hour to set, so you can cast multiple copies in an afternoon.

 Above is the master for one side of an ex WL&WR six wheel coach which was converted to carry turf during the Emergency [aka WW2]. Made from plasticard sheet & strip, it was quite a few hours work, but worth it in terms of then being able to make multiple copies. When finished, it was mounted in a low walled box [more plasticard] to take the moulding material.

 Here's said mould, ready to take the resin and below is one cast side.

 Another side, two ends and a floor, assembled with cyan, and you have the coach body, which then had an Alphagraphix etched brass chassis attached as shown with the completed models below.

 Have done all sorts of other models, mainly wagons, for both broad and narrow gauge, as per more masters below.

 If you are not ready for 3D printing yet, would say resin casting is definitely worth a try.

[Paul 34F]

It has already dawned on me, there are two distinct paths to follow here, which represent most members of the railway modelling community.   This affects how a vehicle should be produced.  It is a reflection of the situation with white metal kits 60 odd years ago.  
 

So the two choices are, one piece complete body shells or a kit of parts to assemble.  Either can be designed to suit RTR chassis or printed chassis can be provided. 

Whilst a one piece shell is attractive for those who feel they may not be able to assemble a kit, a set of parts maybe more practical to allow for variations within a class of vehicle.  The latter would dependent on the quality of the design and the tolerances of the printer used.  As Rob has shown, not everything already available is correct.  This is a reflection on the Designer and what this person believes is correct.

As for the time required to print, it seems slow, but I appreciate, you can go off and do something else.  The newest printers have a built in camera, so you can always keep an eye on the process via a smartphone.  I have pondered whether you could print off a set of masters to make a mould, or you could just print a mould and cast items from this.

The options and possibilities seem endless.     I really need to get some equipment and give it a try.

Paul

 

 

 

[2996 Victor]

3D printed kits are quite (well, becoming increasingly) common in aviation modelling.

Given that I know nothing about the process of creating a 3D file for printing, printed kits for railway models would seem to be a good method of production. Presumably, for instance, a wagon's sides and ends printed flat would print more quickly than as a complete model?

Please excuse my ignorance!

Cheers,

Mark

Edited yesterday at 06:41 by 2996 Victor

[Colonel]

Presumably if, say sides and ends were printed, as per my castings, then being more 2d than 3d, would be quicker to CAD?

[Rob R]

Printing flat with FDM printing (the hot glue gun type) doesn't always make it quicker for the whole "kit" as the volume of filament to be extruded is very much the same. It is possible to get a better quality print but as the face sat on the build plate will not have any detail it is best suited for vans and coaches.

My current fiddlings are to see if the technique can produce consistent prints of suitable quality for open wagons, I know I can with resin printing but there are potential issues with H&S side of things and the smell isn't always domestically acceptable.

It is a "hobby within a hobby" and I appreciate it is not every ones cup of tea but  it has the potential to allow more modelers to wander off the beaten rtr track and explore new projects including just about everything steam era in Ireland.

Edited Sunday at 21:22 by Rob R

[Rob R]

4 minutes ago, Colonel said:

Presumably if, say sides and ends were printed, as per my castings, then being more 2d than 3d, would be quicker to CAD?

Probably not.

A lot of the CAD is "copy and paste", it is the compromise between drawing it dead scale and reliably printable that takes the time, that and getting the prototype info in the first place.

 

Ideally  flat sides need doing in a material that can be glued with MEK or similar (PETG), easly done but just another stretch on the learning curve.

[Northroader]

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.

[Mol_PMB]

My stumbling block is that I learnt CAD in the era of 2 dimensions and my brain just can't work out how to draw in 3D. Old dog, new tricks etc.

I can visualise how 2D components can be assembled into a 3D shape and so I consider myself competent at designing etched kits, laser-cut structures etc.

For 3 dimensions I'm happy to buy from others whose brains work better than mine. Many thanks to all of you!

I do have a good resouce of drawings, measurements and diagrams of Irish rolling stock, and happy to support others projects where I can.

[Bullet_Wanderer]

I'd be happy to throw my hat in the ring here, haven't had any experience 3D printing, but am decent at digital modelling! Give me a prototype diagram and I'd be happy to have a stab at creating a model for 3D printing, bit of trial and error! Metrovik was kind enough to do a test print of my J26 model (I'll let him share the early results here if he wants to), and for a test print it came out pretty decently! I redesigned the model a little bit to hollow out the inside for potential mounting to a ready to run chassis and motor. 

As for me I'd be happy with a static model, so I split it up into the different components here that would make that up. Reading through this thread though, I wonder would I be better off splitting the model up further, to be later assembled?

Probably a sort of flatpack version if that makes sense. Little details like coupling hooks and vacuum pipes might be better done through a different medium, but for a base engine to build off of I reckon it could be a good start?

[Paul 34F]

I can sympathise with Mol_PMB, I too was trained in the world of 2D drawing, (both hand drawing and early CAD systems) and have the ability to visualise 3D objects.  It is a steep learning curve, however, I’m following tutorials on the internet and I’m able to recreate the item in the video.  I have to rewatch the footage several times over, due to trying to keep up with the speed of the operator.  
 

Bullet_Wanderer, your recreation of a J26 is impressive.  If you were to split it down further, consider separating the cab/bunker and probably the chimney.  It would allow different versions to be created.

One question, what wall thickness have you selected?

Kind regards

Paul

 

[Mayner]

On 18/5/2026 at 7:37 AM, Colonel said:

 Further to this morning's post, here are some photos of the basics of resin casting.

 First the 'stuff': below is what you need to make the mould - a tin of 'goo' and the setting agent/catalyst. One part of the latter to 20 parts of the former. Mix and wait 24 hours for it to set.

 The other stuff is the resin - two parts mixed equally, which take well under an hour to set, so you can cast multiple copies in an afternoon.

 Above is the master for one side of an ex WL&WR six wheel coach which was converted to carry turf during the Emergency [aka WW2]. Made from plasticard sheet & strip, it was quite a few hours work, but worth it in terms of then being able to make multiple copies. When finished, it was mounted in a low walled box [more plasticard] to take the moulding material.

 Here's said mould, ready to take the resin and below is one cast side.

 Another side, two ends and a floor, assembled with cyan, and you have the coach body, which then had an Alphagraphix etched brass chassis attached as shown with the completed models below.

 Have done all sorts of other models, mainly wagons, for both broad and narrow gauge, as per more masters below.

 If you are not ready for 3D printing yet, would say resin casting is definitely worth a try.

I am not sure about the situation in the UK but its become increasingly difficult to source resin casting supplies in this part of the World, my two main suppliers ceased trading during the past 20 or so years.

Years ago I cast wagon sides and ends using similar methods based on a Model Railway Constructor article published during the 1970s (4mm LSWR layout), more recently (15) or so years ago I produced a batch of one piece narroow gauge open wagon bodies usingv a 2 part plug mould cast from a brass master, also used Shapeways prints as masters for resin castings. The wagon body (with interior planking) was intended to fold up from a single sheet of etch brass, with separate strapping and end post detail. The Shapeways print was used as a master for the resin fuel tanks used with my initial (2014?) run of CIE 4w Heating Vans, tanks on the two more recent releases of the kit were 3D printed from my original 3D CAD (3D Model)

Personally at this stage I find that it take a similar amount of time to perpare a master/scratchbuild a model using traditional methods as it does to design a model for 3D printing. One of the advantages is that I find that I can modify an existing model with quite minimal effort on the computer screen. Ending up with 3 variations to the CIE 20T Goods Brake , 2 variations to of the GSWR/GSR/CIE 10T covered wagon and potentially Great Northern, GSWR, Midland variations to the "Standard" IRCH open wagon by quite minor changes to the CAD work chages to buffer shank & w iron design.

 

[Colonel]

An internet search showed a variety of resin castings kits from about £40 upwards in the UK. They tend to include things like rubber gloves, paper cups, lolly sticks and so on for mixing. Fine for a first attempt, but cheaper just to buy the material. One thing to note is that the silica mould may only last a few months once opened. After that, it doesn't set. The two part resin lasts longer.