MGWR 7 ton van

[Maitland]

This represents the 1893 series, drawing in Ernie Shepherd's book. Created using Solid Edge community edition, and not quite complete- I haven't worked out how to do the door fastenings, obviously the undergear and roof are missing. It's actually to 4mm scale, but the STL (about 3MB) can be scaled. When reasonably complete, I intend to put this on Github so anyone can use it. I got a quote to make it from the Chinese company Seeed Studios, who I've used in the past to make very good PCBs, about $26 for two, including shipping and taxes. Actually I'm not very sure what they've quoted for, they could have taken dimensions as mm not inches, a bit like Spinal Tap's Stonehenge  (how do I check the dimensions field in STL?), and I can't contact them as it's Chinese holidays. Who would grudge Chinese workers their holidays?

 

Anyway, you resin printing experts: should I do the roof/ buffers as separate parts or will it print with them in place? I can't try it out as my order for a printer and washer hasn't been delivered yet, boohoo. Has anyone tried printing open- spoked wheels?

[jhb171achill]

Wow!! That looks great! Will it be possible to purchase a complete one? 

[Past-Avenue]

Hi Maitland 

In my experience you are best to print as one complete wagon. I have tried to print roofs separately and could not get them to my satisfaction and I now print as one unit. 

The ranks grain wagon is the only one that I print in three parts and it works out fine. 

If you need any further information please feel free to contact me. 

Enda 

[leslie10646]

Hi @Maitland. First, good luck with this interesting project. Like @jhb171achill, I'll have one too, please!

@Past-Avenue is giving you good advice, straight from The Stables, if not the actual Horse's Mouth. His work to produce my two cattle wagons and the van was done as a single print and the results were quite excellent. (Still available from me, of course!).

Our good friend @Mayner has used a 3D printer in Hong Kong and I can attest to the total excellence of their printing.

But rather than face the Slings and Arrows of the taxman, why not persuade @Past-Avenue to do it?

What about it Enda? I think they'd sell.

[Mayner]

While its feasible (with a suitable choice of resin & printer) to print a wagon with separate body, chassis and roof its often simpler, quicker and cheaper to produce a wagon as a single print.

The JM Design range of wagons were printed in full size 'bottom up" printers using specialist engineering resins in print houses in New Zealand, Singapore & China. In the end our Chinese print house proved the only one capable of consistently delivering consistent high quality prints at a reasonable cost.

Interestingly packaging (card box & foam insert) was a significant cost factor, also wheelsets, couplings, decals & paint (all  quantities).

Being located in New Zealand business was registered for GST (local equivalent of Vat) in order to claim back GST/VAT paid on expenses plus annual Accountancy Fees for business accounts, soo selling kits or model trains is an expensive business with hidden costs.

Enda @Past-Avenue produces a modified version of my Grain Wagon under license as it was not feasible to reliably print the original verison on his printer.

 

In the end I discontinued producing 3D printed wagons, with relatively low level of demand for Irish outline kits/batch built RTR items it was not worth the effort financially

[leslie10646]

5 hours ago, Mayner said:

While its feasible (with a suitable choice of resin & printer) to print a wagon with separate body, chassis and roof its often simpler, quicker and cheaper to produce a wagon as a single print.

The JM Design range of wagons were printed in full size 'bottom up" printers using specialist engineering resins in print houses in New Zealand, Singapore & China. In the end our Chinese print house proved the only one capable of consistently delivering consistent high quality prints at a reasonable cost.

Interestingly packaging (card box & foam insert) was a significant cost factor, also wheelsets, couplings, decals & paint (all  quantities).

Being located in New Zealand business was registered for GST (local equivalent of Vat) in order to claim back GST/VAT paid on expenses plus annual Accountancy Fees for business accounts, soo selling kits or model trains is an expensive business with hidden costs.

Enda @Past-Avenue produces a modified version of my Grain Wagon under license as it was not feasible to reliably print the original verison on his printer.

 

In the end I discontinued producing 3D printed wagons, with relatively low level of demand for Irish outline kits/batch built RTR items it was not worth the effort financially

Folks, take note of John's comments on the "bits" you need - a huge addition to the cost - £5 for two axles of wheels, another couple of quid for couplings (more for some types), decals at least a quid a wagon, usually more like two and to keep the price that low you're buying a hundred and might never sell that number of wagons.

Pre-1970 wagons are always going to look expensive beside Accurascale's ones, but that's the price of playing minority sports?

[Northroader]

Me, too [in 7mm)

[Angus]

There has been a bit of a debate going on in our 2mm scale group about the best way to use 3d print technology.

The consensus seems to be for wagons a 3d body on an etched chassis with 3d details such as buffer and axle boxes is the ideal.

This also assumes you have access to a chassis etch or the skills to draw one up.......

 

Edited Saturday at 12:06 by Angus

[leslie10646]

32 minutes ago, Northroader said:

Me, too [in 7mm)

And me, Bob! I'd forgotten my 7mm activities as I'm in the 4mm house!

I hope that you are well. Your locos look great on my little shed layout, which I hope you've seen?

Leslie

[Mayner]

3 minutes ago, Angus said:

There has been a bit of a debate going on in our 2mm scale group about the best way to use 3d print technology.

The consensus seems to be for wagons a 3d body on an etched chassis with 3d details such as buffer and axle boxes is the ideal.

This also assumes you have access to a chassis etch or the skills to draw one up.......

 

In 4mm Irish outline demand/interest has been primarily RTR with little interest (sales of) kits or scratch-building components. Our best selling 3D printed wagon RTR CIE Goods brake sold approx 100 units in 5 variations/batches of approx 20. Others types of RTR wagon varied 10-30, little or no interest in 3D models in kit form.

Etched kits tended to sell 10-20 units, though MGW Horsebox & Meat Van less than 10.

Different skill sets & types of software designing 3D models and 2D drafting (etched/laser cutting etc). 

3D printing whether your own printer or a bureau, min quantity is one model, while etching involves a tooling or set up cost (min size sheet approx A4) plus a cost per sheet.

Another issue is achieving an acceptable standard of finish with a 3D print in 2mm, its challening enough to achieve an acceptable finish with a resin print in 4mm, while some processes only come into their own in 7mm and larger scales.

[Angus]

1 hour ago, Mayner said:

Another issue is achieving an acceptable standard of finish with a 3D print in 2mm, its challening enough to achieve an acceptable finish with a resin print in 4mm, while some processes only come into their own in 7mm and larger scales.

Hi Mayner,

There are quite a few of our group who are now producing decent quality prints in 2mm.

I suspect this is due to constant fettling to perfect the print, something that wouldn't be viable on a commercial basis, but is encouraging for the hobbiest.

Cheers

Angus

 

[2996 Victor]

This looks fantastic! If it could be made available for those of us without a printer, that would be amazing. I'd be up for four or five!

Cheers,

Mark

[Maitland]

Thanks for all the comments, and sorry I've been slow responding- away for bank holiday weekend. 

I don't intend to market anything- I had quite enough of that being self- (un)employed for 20+ years, the world's worst businessman. If I had a gold brick I couldn't sell it. But anything I design will be made available freely for anyone to use, via Github probably, along with details of where it can  

As for the cost, well, count the hours of conventional scratch- building or high- quality kit assembly, and charge yourself- even at the minimum wage or less, it's not a cheap hobby.

Now what I'm really after is to pick your brains. I've not done resin printing before, so what resin gives an acceptable level of detail (what level is realistically printable? 0.5mm, 0.2mm, 0.1mm?), what about thermal stability, do I correct for shrinkage or does the software do that, where to put supports, which way up to print it, etc. etc. I don't even know what questions to ask yet - but you've done it and probably learnt the hard way. If you've posted about this elsewhere, links please.

Odd questions: If I have a van or carriage with a roof and a floor, or a tank wagon, how does the surplus resin get out? Can I print buffers, brake gear, door handles etc in- situ, or are they best separate? How do you get axles into the bogie or chassis? Is there any snazzy trick to allow an axle to float for 3 point suspension? What sort of paint for what sort of resin? 

I'm sure I've got dozens more questions coming  as soon as the computer- generated ideal meets the sticky, messy real world.

[Mol_PMB]

My preference would be for fine details (e.g. door handles, brake gear) and potentially fragile parts (e.g. buffers) to be separate. They aren't very robust as printed components, more likely to cause a high reject rate and be easily broken when the model is handled. If I was building the wagon I'd replace them with metal parts anyway. 

 

Incidentally I found the original MGWR wagon diagram for these vans in the IRRS archive, along with diagrams for many other wagons.

[Mayner]

1 hour ago, Maitland said:

Now what I'm really after is to pick your brains. I've not done resin printing before, so what resin gives an acceptable level of detail (what level is realistically printable? 0.5mm, 0.2mm, 0.1mm?), what about thermal stability, do I correct for shrinkage or does the software do that, where to put supports, which way up to print it, etc. etc. I don't even know what questions to ask yet - but you've done it and probably learnt the hard way. If you've posted about this elsewhere, links please.

Odd questions: If I have a van or carriage with a roof and a floor, or a tank wagon, how does the surplus resin get out? Can I print buffers, brake gear, door handles etc in- situ, or are they best separate? How do you get axles into the bogie or chassis? Is there any snazzy trick to allow an axle to float for 3 point suspension? What sort of paint for what sort of resin? 

I'm sure I've got dozens more questions coming  as soon as the computer- generated ideal meets the sticky, messy real world.

Designing the 3D model is the simple part there is quite a learning process involved in converting a model into a physcial object, printer resolution and choice of resin are significant factors.

Resolution.

Typically 1mm is considered the minimum thickness/girth for a resin printed object & our designer tested/pushed these constraints to the limit in models like the 20T Brake and GSR Grain and found that it was necessary to increase the thickness of components such as axleguards, brake linkages to achieve adequate strength/print reliability

Print quality/acceptable level of detail is related to printer resolution, although our initial supplier produced excellent prints we began to experience quality problems after we shifted production to a supplier who used a machine that printed to a higher resolution. Our designer formed strapping/raised detail as a skin on planked wagon bodies, no problem with our initial locally printed models, but planked groves running through strapping/raised detail after we shifted production.

Solution depth of strapping deeper than grove, rather than modelled as a surface feature or skin.

Resins and print set-up (slicing software).

Many of the commonly available resins are too brittle for use in 4mm stock. My preference is for an engineering resin with resilient or good tensile properties. (I currently use Australian Monocure resins (non-hazardous (flamable/explosive))  Solvent based resins with IPA clean up, basically "intrinsically safe" electrical gear and ventalitation system, and odors.

I use a "Anycubic" Printer with the origonal slicing software although no longer supported and 'auto support' application no longer functions.

Selecting resin and print setting is basically a process of experimentation, ideally small simple projects different resins and printer settings.

 

4mm Axleguards and small detail parts 45º set up & print settings in accordance with manufacturers recommendations, parts orientated to minimise warping/twisting as a result of experimentation, Monocure 'Tensile?" resin approx 20 repeats.

Large Scale 1:20.3 handbrake wheels and loco number box. settings as above.

Draining resin out of 3D printed part.

Not really a problem I experienced, with desktop printers parts are printed upside down and at an angle, otherwise form drain holes in 3D model before printing.

Printing small/detail parts.

I have printed parts including buffers brake linkages wagon underframe on over 200 wagons. Door handles/grab rails not really feasible.

It might be worth checking with the local library service/evening classes on 3D printing.

[Rob R]

I would print it "as is".

My resin printer is an Elegoo Mars 2 pro, about three generations old in printer terms and my go to resin is Elegoo water washable transclucent - usually green but other colours are available.

For the S scale open wagon pictured below (GNR of england 4 plank) I went through a ton of prints trying to get it to print with a floor and in the end decided that for the sake of a bit of plasticard it was easier to do it floorless. As a bonus, it also sits horizontal to the build plate and reduces the print time.

Screen shot of supported model

a couple of views of one of my prints being turned into a work of art by Scott Willis

And the finished article

For your van in 4mm scale I would do the roof seperately, in 3 pieces, 2 end sections and the centre beam, not sure about the best way of doing the canvas roof doors. Axle boxes and springs easy enough to draw and print. Buffers print with steel heads (Gibson? Wizard Models?), W irons - use standard gauge etches but put a set in the W part, angle it out and then bend it staight down at the level of the bottom of the solebar (sorry that would be so much easier with a picture), it is only a mm each side. Brake gear, mixture of printed and commercially available etches.

I am looking forward to printing your van in S, Paul Greene will need a dozen or so for Broombridge.

Are you UK based? Are you coming to Railex in Aylesbury at the end of the month? If so please come to Trowland and we can have a chat.

Cheers

Rob

[Mol_PMB]

A phone photo of an MGWR 7 ton van diagram in IRRS archive. It's not actually the same one that's in the book although the main dimensions are the same - it seems there were several variants of bracing and vents.

Note that this isn't a square-on image so please don't measure and scale off it! I hope to convince Richard McLachan to do his proper photography process on the wagon diagrams so they can be published and shared - there are lots of them.