Diesel in a Day – Scratchbuilding an NZ120 DFT

Condensed from a series on Motorised Dandruff in June 2009  Diesel in a day: DFT from scratch

Condensed from a series on Motorised Dandruff in June 2009  Diesel in a day: DFT from scratch

DB says: It’s been more than 10 years since I made an NZ120 loco top from scratch, so I’m going to shake the cobwebs off myself and whip up a DFT.

Before you ask, it’s not going to be cast, RP’d or etched. Instead, it will be quick to make, cost next to nothing and require almost no skill. And as long as you don’t make a complete bollox of it, will look just as good as a cast, RP’d or etched top from three feet away.

For those who haven’t scratchbuilt in NZ120 before, it’s really quite easy, so much so that I’m going to try to make it in a day if I can, and then, assuming I remember to take a few pictures, will write up the experience for a few posts on the blog. Starting now.

The night before the day following.

If you want to play along at home, you might have your own plan, but if not, never fear, for I’ve included (attached to the end of this article) one I hodgepodged up this evening, based the drawings in an old Rails article. Interestingly, or perhaps strangely, that original plan had a nose that was way too steeply raked and the position of the cab windows was incorrect as well, as were quite a few of the DFT details. To fix these I found a side-on picture of a DFT I’d taken, placed it behind the plan so it was partially see-through, and traced in the new details. I won’t promise it to be a million percent accurate, but its not bad. But I digress.

Beside several copies of the plan, I’ll also need…

  • A sharp knife with a fresh blade or two
  • Metal straight edge ruler or something to guide that sharp knife.
  • Styrene (various)
  • Clear styrene (or business shirt boxing – anything see-through, thin and flat) for windows
  • Wire for handrails
  • Mesh for the rear radiators
  • PVA, plastic, contact and super glues
  • An old US N scale loco shell (almost anything EMD will do)
  • Miscellaneous bits of miscellaneous stuff – wire for brake hoses, misc bits of plastic and paper of various gauges and who knows what else.
  • If we get that far: paint and decals.
  • Oh, and eventually an N scale sd40-2 chassis (or a dash 8 if you must) to put it on. Kato would be nice if you have one handy.

Right… I’m off to get that stuff together and clear off a few inches on the workbench. I’ve got a busy day ahead.

Note: I don’t know what the blog software or your printer will do to this plan, but you’ll probably have to scale it down until the length over couplers (the "16688" dimension on the DFT side view) is a smidge over 139 mm. For folks running Windows 1992, even you can right click the above, ‘Save Target As’, open with Microsoft Paint, and in print setup, there is a scaling function. Or use a photocopier. Or maybe you have your own plan already. Some conditions apply. This offer not available in the Chatham Islands.

Diesel in a day: DFT Part 2

DB says: The time is 1:10pm. Gentlemen, start your modeling knives.

Let’s do the painful bits first, so grab those plan copies (you did print out some plans didn’t you?)and we’ll make some hood sides. A long time ago I used to painstakingly scribe the hood doors into plasticard, but hit on this idea in the late 80s when I used to have 1/64 vision: cut out the doors from a photocopied plan and stick them on the styrene long hood. It gives the model a 3d look, the panels are marked out nice and square for you, the printed panel, hinge and door latch detail will faintly show through the paint (then again you could always cut those out too if you were mad). And if that hasn’t swayed you: it’s less work than scribing and virtually impossible to screw up. Of course if you’re more comfortable scribing, scribe away.

Cutting around all the panels and door hinges can be time consuming, but the work can be sped by making all the (mainly longer) up-down cuts in one go and then spinning the plan 90 degrees to do the short ones.
We’ll cut the cab out of paper as well (gasp – I’m sure this is not how Alec Fenton made his masterpiece 1:64 DF), but instead of sticking it onto styrene, we’ll use clear plastic instead. This will give the cab structural rigidity, gives flush windows, the paper is much easier to cut holes in than plastic, you should be able to see the printed ‘window rubbers’ through the paint, and again, it’s all marked up nice and square for you. In the plan attached to the first DFT post, I included some cab fronts devoid of handrails, horns and other stuff that might show through the paint later on as well as the two different cabside window layouts. Yes, I should have included two cab sides of each….
I use a SHARP knife and a metal ruler for the really long cuts and the all-important cab parts, while doing the rest freehand. Do the cab windows before cutting the cab out, or you’ll likely break the really thin windowframe sections. I do the ‘rounded corner’ windows by cutting the four sides into the start of the curve and then use the point of the knife to ‘cut the corner’ straight. If that makes sense… so in actuality mine are octogons with long vertical/horizontal sides and tiny sides in the corners. That still doesn’t make sense does it… When you’re done with your cab, turn it over to the unprinted side and check out your windows – sometimes the black window outlines can disguise a window that’s not so square. you could cut all the panels out individually, but I tend to keep them together in a long string and scribe the 5 or six in-between panel lines after everthing has set. This time I didn’t do this until the paint was on. Now it’s time to cut out some plastic to stick your paper whotsits to (above). If you have your chassis handy, now would be a good time to check how wide it is by eyeballing it against the back wall of the plan and determining whether you can fit it inside a scale-width hood, or whether you’ll have to fatten up the hood and have thinner walkways. The Kato SD40-2 lets me do a narrow hood with quite thick (about 1.5mm) plasticard sides for strength, the older Bachman Spectrum -2s require thinner plasticard and/or a wider hood to fit.
I cut out some holes for rear radiators and rear horn, and then attached the paper cutouts with a thin smear of PVA as I’ve always done (not too much or your panels will wrinkle). A wee way in, I noticed a problem with some of them not sticking, so I used plastic glue from then on in. I swear I’ve never had this problem before (as the bishop said to the actress). For the cab sides, I cut the clear plastic backing a little smaller than the paper in the fore-aft dimension so the paper wrapper would overlap the cab front and rear walls and give neat corners.
If you get PVA on the actual windows, a cotton bud works wonders. If you get others glues on them, well, you’re screwed really. It’s all or nothing here folks!

(Above) So here we go – paper cutouts are stuck on the hood sides, the port-side blower duct and side air ducts (from layered rectangular styrene rod) have been built (one attached), the cab paper bits have been stuck onto clear styrene and a floor plate has been cut out of 1.5 mm plasticard to fit the chassis snugly.

I’ve made a rear cab wall out of plastic to give the cab more strength as well, made in reference to the front cab wall, not to the plan. If I made it to the plan, inevitably I’d end up with different front and rear roof profiles, and this is quite the pain to deal with later.

Walls assembled.

I spent some time thinking about the corner angles on the long hood roof, but fell back on an old ‘cheat’, where I added one thin piece of sheet on top to keep the sides together, and then attached a 1mm thick piece the width of the

roof-top surface

on top. This gives a stepped profile that you can see in the pictures rather than the nice flat angle you’d expect – but never fear, we’ll cover that with paper (the new miracle product) in the next step. The reason I do this rather than scrawking styrene to the angle or sanding balsa is that this gives me a nice straight roof profile – there’s no way I’d sand something this straight. The paper with its glue and paint is plenty strong as well – the DF6277 and 6064 shells were built about 16 years ago with this technique.

And here it is. You can see the ‘stepped plastic profile’ in the foreground above the blower duct and at the rear, while paper panels cover the middle engine room section with a nice angled profile. These roof panel pieces are cut out individually (again to add some ‘3d’ to the roof) using the plan as a guide. Luckily 🙂 the DF and DFT side drawings line up on the plan, so you can put a ruler between the roof sections of them both, cut some lines vertically to get the panels the right widths (note that the are not all the same width). and then cut the panels to length so they will wrap over the roof – do one first to get it right, then cut all the others in one foul swoop to match.

Diesel in a day: DFT Part 3

DB continues from where we left the last episode….

Now it’s time to start attacking that N scale donor shell for some detail parts. I used the SD40-2 top’s dynamic blisters (sanded down a little to make them a little less angley) and an SD70 fan for the dynamic brake fan (as it’s larger than the dash 2 fans, although you can get away with either). The main intakes can come from almost any American engine shell, but I used the SD70 ones again – they’re a little bigger. On the DFT, the one on the port side is longer, extending further aft. Avast landlubbers! Raise the mainsail and deploy the sphincter to leeward! I know these aren’t the ‘official’ locomotive-navigation terms, but they make far more sense to me than No1 end, A side. Note also the rear horn recess made by pushing the paper panel down into the notch created for it earlier (just north of the south radiator at about 2pm). The DFT roof adornments took longer to make than expected given that they look pretty simple. I scrawked a thickish piece of plasticard for the raised manifold cover (it probably should be a little taller) and used the exhaust port from the SD70 shell after severely thinning it in most dimensions. Close enough.

With the heavy lifting done, I figured it was safe to install the cab, and a minute later it was in place. A nose was then made from thick plasticard and left to set. Cripes, it’s been a long afternoon. Time for dinner methinks. Time is 6:30.

Post culinary replenishment, the nose was sanded to shape and attached, along with a few other detail items. The cab roof was made from very thin aluminium sheet – highly recommended. That cab corner joint looks a little messy toward the bottom in the closeup picture but I don’t remember noticing that at normal magnifications. I hadn’t noticed how the laser printer dithered the window rubber surrounds either. Maybe I need glasses.

You may also be able to see how I deployed my 25 year old razor saw to cut a notch along the front of the anticlimber. Later on I’ll stick a handrail in there.

Some false rear radiators were made from roofing styrene painted gray, and the see-thru mesh attached with contact and superglue. Here the big roof one is about to go on.

9:25 pm and I’m pooped. Technically that’s the top done in a day. At least the top of the top. Less than a day really given the 1pm start. I should go on to add headstocks and the undergubbins to finish it off… but… the only TV show I watch – Two and a Half Men – is about to start.

It’s all about the priorities.
More to follow, so don’t touch that dial.

Diesel in a Day (or two): DFT Part 4

A few days hence, DB returns to the safety of the train room.

When we left our last exciting episode, things were pretty much complete above the side sills, so that left the nether regions to do. The DFT s(and DFs) have a big girder under the sills, but I don’t have any plastruct girders and attempted to make something credible up out of some flat strip with a tiny square rod stuck on one edge. These are lying under the DFT cab in the pic below although they’re pretty hard to see in this pic.

I also fabricated headstocks – the front one has a little more detail than the back as I rarely look at the back of these things when they’re chugging around a layout. These were each attached to a big square styrene rod to keep things at 90 degrees to the floor. These rods will also be the mounting place for the couplers later on. Speaking of couplers, as I’m not 100% sure where they will sit at this stage, I made a reasoned guestimate and cut a decent sized hole for them in the headstocks that I can with paper later on if need be. Good old paper.

The homemade faux-channel was then glued under the floor between the ends of the rods – all carefully calculated so the ‘girders’ would sit outside the Kato mech’s pickups.

For my other DFs I made all the fairings, steps, jacking pads/sandboxes/etc by cutting them out of the paper plan and simply glueing them on. These have for the most part held up pretty well over the past 20 years but this time I went to the other extreme and made them all out of styrene, mainly out of solid rodding (I just love all those strips and shapes and squares and rectangles and things).

The main air tanks could have been stolen from the SD40-2 shell as I’ve done in the past , but they are a little small in diameter, so this time I made them out of airplane-kitset-sprue stuck in a big drill and attacked with sandpaper to round off the ends. The poor man’s lathe. I didn’t bother with that last step for the two wee cyls under the cab on the port side.
I went to town and made a few other details that I could see in the grainy protype pictures available on the web from plastic and wire (traction motor cables). The most silly being the wee lifting eyes above the bogies and on the headstocks. I’m not sure whether much of this will be visible when the paint goes on… A few lift rings for the roof, a sinclair radio antenna, ditchlights, wipers and brake hoses came from my collection of US N scale detail bits, but could just as well have been made from styrene and fine wire. Or left off. The headlights front and rear came from US shells, as probably did those horns, which are actually pretty awful. A lot of these details seem to vary by loco so again, mine might be a bit ‘representative’ rather than an exact copy of a specific loco. It’s the effect that matters in NZ120.

Despite that comment, those with 20/20 memories may have detected that the cabsides (and the previously grossly oversized MU connector on the nose!) have been replaced since last time. I was going to make a black DFT with powdercoated sliding side windows, but have since decided to do 7132 in blue, which still has the original style side ones.

I wish it still had the original front windows rather than the cross-eyed triclops look as well…

Diesel in a day (or three): DFT Part 5

I ended my second afternoon of DFTing by painting her up blue, yellow, gray and black, and now that the paint is dry, its now time to wrap things up by documenting the third visit to the trainroom.

Going back to that epic post on colour, I began the session by dulling down my deep sky blue and dark gray with a wash of rapid-drying light gray acrylic which has made it look a bit more like the real 7132 trailing in this shot from a few months ago (which has just this week become my inspiration for this model).

I absolutely loathe doing handrails, but once they’re done they make everything look more finished. I used very fine brass wire this time instead of my usual piano wire and the superthin ones look waaaaay better. The light attached to my workbench (the black thing in Ev’s workbench post) has a (scratched) plastic magnifier built in that has never been used until painting those handrails. Boy does it make that job so much easier. My eyes must finally catching up the rest of me.
Tranz Rail’s flashy decals were from the superb Etchcetera (Andrew Wells) DC set – the cab numbers aren’t the right font for the blue livery, but they will do for now. I gave the loco that ugly ‘patch job’ look with one more wash of the gray paint in an approximate rectangle. For some reason, many of the DFTs got a much lighter patch than their underlying blue paint. I might cover some of these ‘finishing’ steps in more detail in future models/blog posts because I forgot to take pictures and I’m sure you’re getting sick of DFT tops by now.

Finally, a Kato SD40-2 chassis for it to sit on: I pruned the shock absorbers and some of the ‘underbrake’ bits off the bogies and made battery box sides from strene. The -2 fuel tank was simply shortened to save time as the end profiles are similar.

And that’s that!


Having not seen a lot of real DFTs in action, I must confess to not being a huge fan of them …last week. This project started out more as something that would be ‘good for the blog’ rather than a loco I just had to make, but once the thing started to come together, I started to enjoy that feeling of making something from scratch and am now quite in love with a model which turned out really well.


Dangerously close. Ditch lights in, but needs headlights.

Having said that, if you are going to have a go at scratchbuilding for the very first time, I’ll warn that the DFT is a more difficult model than I’d thought. There’s all the lumps and bumps, the underframe stuff, the painting of the raised walkways and yellow stripe – that make it quite a bit more tricky than doing, say a DC, which would be a more straightforward scratchbuilding project.

And -before I forget – something I forgot to do on this DFT, was to make the whole top about a mm shorter than it should be as I did with my DFs. This would have tightened up the gap between the rear bogies and the back end a smidge, although looking at the pics above it doesn’t look too bad.

Scratch That

I started this project with the comment “Before you ask, it’s not going to be cast, RP’d or etched. Instead, it will be quick to make, cost next to nothing and require almost no skill.”

That wasn’t intended to be a swipe at the technologies that will turn NZ120 upside down in a few years. But… isn’t that what everyone said ten years ago? I’ll reiterate from a few months back: manufacturers rarely produce products for love, the market is tiny and bringing products to that market is an incredibly time consuming and expensive proposition. You do the maths.

My point is this: you can wait for things to drop into your lap, but you can also make something out of nothing today, and get a great feeling of accomplishment from doing it. Surprise yourself and then surprise someone else with it and perhaps get them interested in the scale. Given the usual 2-3 foot viewing distance, there’s no better scale than NZ120 for scratchbuilding stuff; which is a good job given the incredible number of fancy kitsets and RTR items available.

So get of that armchair, bring that beer with you and have a go. After all, this DFT top isn’t too bad for a ten dollar, paper-and-plastic, two and a half day effort eh? As Bruce Forsyth used to say : “Hope you’re all doing this at ‘ome!”

3 Replies to “Diesel in a Day – Scratchbuilding an NZ120 DFT”

  1. Computer controlled cutting

    Mr. Druff,

    I received a flyer from a local craft store and discovered an amazing tool!

    It is aimed at the Scrap-Book hobbiest, but I think that it will revolutionize the Card-Stock modelling Hobby!

    On doing a little online research, I’ve found two different machines that both work like stylus printers, but they cut paper and cardstock.

    Robo Craft:  http://www.craftrobostore.com/

    and the one that was in the flyer

    CriCut: http://www.cricut.com/

    There’s pros and cons to each machine, but they both hold some promise.

    I think that these machines will handle thin styrene and the CriCut also has a metal engraving head…

    My innitial hesitance at getting one was because the CriCut operates with expensive font cartidges.

    But I found out that there is also software so you can make your own designs…

    Sure Cuts A Lot: http://www.craftedge.com/index.html

    I’ll post this message in the forum for discussion….

  2. DF in a day..

    Heres my attempt. 5 Hours spent on it thus far.

    Suprisingly simple with the right materials. “The thought of the thing is far harder than the thing itself…


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