A 3 Foot 6 Interlude - 3d Printed bits

DB ponders and then stirs...

Two things NZ120 needed twenty years ago, were a simple module standard (done!) and some quick, cheap, quality wagon tops. Maybe nothing too fancy, but something to give those less comfortable with scratchbuilding the ability to easily make a train that looked 'right and proper'. At the time I wondered if this might have to be a run of injection molded LC tops, but time has moved on, so technology and the efforts of a few CAD designers has solved the problem.

While we made some initial forays into CAD and 3d printing/laser cutting 10-15 years ago, it was Peter Bryant and his KiwiTrains blog who really got the ball rolling big time. Designing a wide range of models quickly for NZ120 and other scales, he made them available on Shapeways. Soon other designers joined in, and I bought a few Shapeways prints more than ten years ago. 

Shapeways items always had challenges - expensive, variable quality of finishes, plenty of print strata, and of course they had to be mailed from abroad, so they were not the solution for the impatient or thrifty. 

In the intervening years, initially expensive DIY home filament printers that spat out plastic spaghetti have given way to higher quality 4k and better resin printers.

Lewis Holden decided to bypass the Shapeways issues by licensing the designs that have already been drawn, adding a few of his own, and printing them domestically as 3 Foot 6 Models.  So you can now get good quality 3D printed NZR models in NZ120 (and other scales) with a much faster turnaround time and low cost shipping.

I have looked at his site a few times and recently decided to order a bunch of models to see how they look. They arrived at lunchtime.

The print quality seems pretty good, certainly these have far, far smoother sides than the last Shapeways models I purchased, with little visible strata, although there are a few areas where the printing process struggles with superfine standalone details like freestanding handrails and undercar truss rods (Shapeways struggles with this too, I have some experience with their saggy Z scale tanktainers). Some curved areas on the models are made up of flat surfaces/polygons rather than truely smooth curves, but that is how they were drawn (way back when) rather than this being any printing problem.

The 3'6 gray resin is surprisingly sturdy, has a nice smooth finish, and details are for the most part rendered very crisply. Long unsupported sides can bow a little, but the instructions detail how to deal with that. My KSs had bowed sides but these were easily straightened in about 30 seconds after their warm water rinse. Quick, easy no problem at all.

After I'd finished entertaining passing vagabonds this afternoon, I had a closer look at an LC and KS top. I bought three KS prints as they are a difficult scratchbuild (has anyone in NZ120? UPDATE: yes, Trackgang has one) and a couple of LCs, because as a lover of the 1980s, you can never have too many, and it would be a good comparison with my existing models, and at 10 bucks a pop, it exactly fits the initial goal espoused at the top of this post.

One LC had one minor strata flaw visible above near the bottom of the sides, as if the model had moved a few microns during the print. This might have been covered by paint but why not eliminate it with a little scrawking with a flat edge. (The top looks bent on the far side here, but that is the phone camera lens)

I also scrawked the inside of the top to thin the slightly chunky design (without which, perhaps it would not print so well?).   There were no other visible imperfections, so a Peco 15 foot chassis was trimmed of its Britishness and installed. The following pic from an entry in this blog from 2008(!) shows the before and after elimination of extra brake shoes, suspension and handbrake, which can be done in about five minutes:

These printed tops are well designed to fit a bulletproof Peco chassis and hang down over the solebars a little, so you can even include the Peco steel weight without the thing sitting too high.

I've never been allergic to Peco couplers either, so they were also installed. I glue them in and have never had a problem with these short wagons, even on crossover pairs of points. 

Not bad to have a wagon after 15 minutes, here sitting next to a Trackgang LPA (which does have nice thin side walls) and a home-cast KP (which is just a hot mess).

The KS top had no visible flaws so it was bunged onto another Peco, it hangs nicely down as well, like the prototype. I had to remove the lower part of the printed coupler slot so the Peco coupler would fit. This was already clear on the LC as you can see in the pic with the upside down LC top a few pics above.

Paint was then liberally splashed on. I did wash all the printed tops before starting this project in lightly-detergented water but didn't bother priming anything. I almost never do, and the paint goes on well here, whereas the Shapeways models tend to suck up the paint. Tamiya NATO Brown with a few drops of my completely magic Game Color Bloody Red were a first attempt at Red Oxide. This looked a little chocolatey on the LC, so a few more drops of red were added and another attempt made, before moving onto the KS: both photographed here before the paint had dried:

Overall, the tops succeed in their goals. The KS is a little chunky in its sidedoor details and seems overscale in width, but that will never be noticed when it's bouncing along in a train. The LC's chunky walls will likely be partially hidden with coal or a tarp.

Overall verdict: bloody brilliant, and great value for money. 

P.s. see Rhys's initial 3'6 purchases here