Cleaning up FDM prints

Cleanup tools for PLA filament

One way in which FDM prints fall down compared with resin prints or traditionally moulded and cast models is in the visible layer lines that show up, even when running the printer right at the limits of its capabilities.

Printed at a layer height of 0.06mm

Most of the time, the layer lines aren't actually that much of a problem, especially for my purposes, which are primarily tabletop gaming. A decent paint job will disguise most of the problem, and during a game, the right silhouette is much more important than the miniscule details on a model.

However, from time to time, I do like to smooth out layer lines or other printing artifacts.

The fact is, there's no instant, automated way of doing that with PLA filament. ABS can be smoothed out (though with the loss of sharp detail) by melting the surface with an acetone fume bath, but that does absolutely nothing to PLA. To smooth out PLA, we have to resort to manual labour.

The tools I use are simple: a couple of fine needle files, and a couple of scrapers I made from stainless steel laboratory spatulas.

The process is also simple: I just file and scrape at the surfaces of the model until they're acceptably smooth enough to be painted. Quite often, that doesn't have to be completely smooth; just knocking off the corners of the layers of plastic is enough to give me a markedly better appearance once painted. It's a tedious process, but not difficult.

I use files in preference to grinding with sandpaper or diamond pads, because the teeth of files actually cuts away the surface of the plastic cleanly, whereas sandpaper, even in very fine grits, just abrades it roughly. You can get a very good surface with sandpaper, but you need to go down through a series of progressively finer and finer grits until the surface abrasion becomes effectively invisible. Files are a lot faster.

Are These The Droids You're Looking For?

I've made a couple of quick, simple Star Wars-ish droids for 3d printing. They're available download (free) at https://www.thingiverse.com/thing:4006771

The one on the far left was printed at 100% scale, the other two at 75%, and they're sitting on laser-cut 3mm MDF bases. The figure is a 35mm WotC pre-painted Rebel Pilot.

Dragons Teeth

I've made myself some modular dragons teeth tank traps for my 15mm WWII games.

They're 3d printed, and the STLs are downloadable from https://www.thingiverse.com/thing:3988309

I was considering putting a low-wire entanglement between the concrete bollards, as was often done to hamper infantry as well as vehicles, but decided against it. I may change my mind later on.

Afrika Korps in 15mm — a beginning is made

Having made the decision to stick with 15mm for my Afrika Korps, I've had the 3d printer working overtime to get the core of the Korps established.

The only one of these models that isn't 3d printed is the painted Panzer IV F1 at centre rear; that's a 1:100 (15mm) PSC model.

I'll do another couple of Panzer IV D, and then I'll get on to transports and things. Anti-tank guns might be an issue, I'll probably have to buy those, along with some infantry. I think I might have a BF PaK 38 in amongst my stuff; I shall have to see if I can dig it out. And I have some other useful bits and pieces from the PSC 15mm early-war German heavy weapons box that can be painted in desert yellow and put into service.

Vallejo Caunter Set

 I just got a set of Vallejo ModelAir paints that I'd ordered some time ago, their Caunter British Colors set.

In fact it's not just for the Caunter scheme, as it includes BSC 61 Light Stone and BSC 49 Purple Brown, used after the Caunter scheme was prevalent, and Khaki Green No.3 which was the standard base colour in which pretty much everything was painted for Home Service and France.

I've been using mix recipes for all of these, of variable reliability, but it's convenient to have a pre-mixed solution that I can just pour out of a bottle.

The colour described in the Caunter scheme as Slate Grey is named here Dark Green, and I don't know if that's because Vallejo are trying to replicate the British early-war Dark Green No.4 or if they've just mis-named the Caunter shade.

I've not even sure if the two paint colours were actually different, in fact. They may well not have been, and simply been named differently in different painting specifications of the time.

I've been using Vallejo German Field Grey for Slate Grey, and that does seem to be quite similar to the colour they've presented here. I've been using Olive Grey for Dark Green No.4, and that looks OK to my eye, so I'll probably just carry on with that.

More Scale Comparison Dithering

Left to right:
Battlefront 1:100 (15mm) PzIII Flammpanzer
3d printed M.Bergman 1:200 PzIII L
Ancient GHQ 1:285 PzIII J

I've been fiddling around the edges of building some WWII desert forces, and now my procrastination and prevarication has come to a head: which scale should I commit to?

They each have their pros and cons.

I already have a few 1:100 (15mm) bits and pieces, mainly British and Italian. I don't have any Afrika Korps infantry, but that's fairly easily remediable, and I have access to digital models of pretty much all the vehicles I'd really need. The down-side is that they take a while to print and they do need quite a bit of painting to look good, and also they're large enough that my 900 x 1800 mm tabletop really doesn't look like wide open desert when I'm using 15mm stuff on it. It's fine for a game like Chain of Command, a bit cramped for something like WRG 1925-50, Fist Full of TOWs or Battlegroup.

1:150 (10mm) isn't really all that much smaller than 1:100, and needs pretty much as much attention to painting as 15mm models. The benefits of that scale, such as they are, don't outweigh the fact that I already have a decent head-start on the models I need in 15mm.

I'm completely new to 1:200, so I would be starting from scratch, needing not only the vehicle models, but also buildings and similar terrain — fortunately, buildings aren't a very prominent feature of a lot of WWII desert battlefields. I can print most of what I'd need, and a tank like the Panzer III shown here only takes about an hour and a half. Painting to an acceptable standard is pretty easy. I'd probably have to use 10mm infantry from somebody like Pendraken, and they'd look a bit big next to the 1:200 vehicles and guns; that is a concern. Also, since nobody I know locally has a 1:200 scale force of their own, I would have to provide the troops for the Commonwealth, Italy, and Germany to be sure of having sufficient forces for a battle. This scale is small enough that my gaming table starts looking acceptably large, and the models are small enough for big battles while still being large enough to distinguish easily.

1:300 - 1:285 is a scale that I already have quite a lot of, and it's a scale that works well on a fairly small table, or makes a moderate-sized table like mine look positively huge. The only issue with it, from my point of view, is that with age my eyesight has deteriorated somewhat, and the models and figures on the tabletop have become difficult to see properly unless I'm sitting right over them. I'm not so blind that they're unusable, but the fact remains that my eyes are not as good as they once were, and it's tiresome having to squint and peer to make out what I'm looking at.

LATER:     I've decided to stick with 15mm for the present moment. It's logistically more convenient in every way than starting on a whole new scale that nobody else in Christchurch has ever heard of, plus, I can build on the few bits and pieces I've already got in that scale.