Detailing Dragon's StuG IV

Article by Stefano Dell'Acqua - s(dot)dellacqua(at)brightsolutions(dot)it
Edited by Rob Haelterman

Disclaimer
This article is based on a post by the author at the Missing Lynx Braille Scale DG:
http://www.network54.com/Forum/47210/thread/1239870152/1240467932/Dragon%27s++Stug+IV+progresses+%28pics+heavy-tedious%29

The finished model should represent a mid-to-late Stug IV "mit Zimmerit".
I choose to represent '23', a Stug IV photographed in Prussia, characterised by Zimmerit, field applied gun bracket, and mixed cement/steel plate add-on armor for the casemate.
I used one box each of Dragon's Stug IV Early and Late, and some parts of Dragon's Stug III and Revell's PzIV.
Photoetched parts are Eduard's, and I'll use a Part gun barrel.
I based my modelling on the well respected Jentz and Doyle drawings, photographs, and books on the subject. A good digital caliper, and much time to spare are fundamental tools.

The basic hull is dimensionally correct. I used the late hull with early front- and side plates so that I had to modify the return roller mounting plates (from three to four), placing them according to the J-D plans. I did that because I wanted the late-style suspension stops (which anyway I removed and scratchbuilt at a later stage- these are oversimplified, rather thick, and misplaced, so I choose the scratchbuilding approach).

I added some bolts (sliced stretched styrene) to the transmission cover (some are misplaced in the kit), and detailed the suspension assemblies with bolts and leaf-spring ends.

Some more bolt heads were added: I used both punch-and-die and sliced sprue techniques.

The rear plate is dimensionally correct, I just thinned the horizontal strakes and substituted the tow hook assembly. The idler wheel/track tensioning assembly is approximate and needs some detailing.

I replaced some parts with more accurate, scratchbuilt items. The exhaust positioning holes are misplaced in the kit, I corrected the exhaust positions thanks to the J-D drawings. Weld beads have been added everywhere where needed, etching the plastic with a sharp 10A scalpel tip.

The front armor plate was detailed with new tow rings -a difficult work to get them right- but the end result is convincing to my eye. If you're interested in figures (I'm not usually, but this time I was curious to know) the lower hull has about 320 parts added to the original Dragon pieces. I must point out that the added parts just improve accuracy, as the basic shape is correct and the position of all of the elements is accurate except for the exhausts, suspension stops, and return rollers.

Upper hull/casemate
I tend to learn more and more about the subject while I'm modelling it- so when I start a new project I do lot of stupid errors. The first thing I did when I started the StuG project was substituting the hull-roof plate to the side of the driver's compartment (Dragon's is overly thick), then I added the driver's compartment to the casemate -WRONG!- the kit's part is quite misshapen, it needs to be lengthened and sloped. I modified it at a later stage, but in these pics it remains as first assembled. The fenders are scratch-built items with photoetched textured plates (Eduard StuG IV late set). Dragon's casemate is dimensionally OK with J-D (I mean to the tenth of a millimeter!) EXCEPT for the gun opening. It is too wide, and the Saukopf mantlet is oversized too as a result. The fix is not too difficult: I cut two new
cheek plates in plasticard of the correct thickness, the plates extending to the base of the casemate, then plied them to the correct angle (J-D helps a lot here!). I then cut away the kit's cheek plates LEVEL with the casemate sloped front plates (actually extending the width of the sloped plates). At this point I placed the new cheek plates respecting the right distances from the casemate sides (I pencil-marked those data on the right plate, it is barely discernible in the pic). Then filled the gap and restored the weld beads. This defect is, sadly, common to the newer Stug III mould.

The kit's Saukopf mantlet is plainly horrible. It's too squarish and, worst of all, oversized in width by more than 1mm. If you modify the casemate opening to the correct width, the shield won't ever fit inside the corrected opening... so again I took J-D and reshaped the manlet, turning the front part in a lathe and shaping the rest with files and sandpaper. Before reshaping takes place, you should be careful to fill the mantlet with epoxy putty- otherwise the sanding process will open holes in the top "corners" of the saukopf. The end result is correct to the tenth of a mm, at least for the dimensions that can be measured with my faithful caliper. Good news? The gun opening diameter is correct (about 2mm) so the replacement barrel will fit just right.
I detailed the front fenders with bolts and springs, added the concrete armor, and replaced the gutter (the kit's one is wrongly placed). Please notice the spare track section on the front plate: In Revell's PzIVs (having wrong sized track-links) just six links fit in this place. Dragon has right-sized links, but the links you get are... eight!!! Why?????? I cut the eighth link, detailed the ends and hollowed two horns, as in the pic of the original "23" I'm basing my work on.

I scratchbuilt the casemate skirts, used a refined Dragon StuG III cupola (some adjustment is needed to fit it), antenna mounts, and fan cover. The pic of the casemate roof of "23" shows that the MG is not mounted, while the Nahverteidigungswaffe seems present (odd enough?). Also, the three-pilzen configuration is well apparent. At this point many hull details are still missing, they will be added after the "rough handling" required for the assembly of the lower hull.

Wheels, or How To Ruin Your Entire Week
Shortly, Dragon's wheels have the wrong diameter, wrong rim diameter, and are a little off in terms of concentricity. Revell wheels are spot-on in diameter (in the pic a comparison of the two, Dragon's gray, Revell's yellow). The rim diameter seems fairly good, but have depressingly shallow detail. I tried an hybridization of the two kinds: Revell wheels with Dragon hubcaps, far from perfect but quite convincing at the end.

First step: how to get them aligned?
I holed through Revell hubcaps with a 1mm drill, then carefully assembled the wheel pairs and inserted a 1mm styrene rod as a mounting pin. Then I built a flat surface with a gig in which the wheels are kept in place. The flat surface keeps the faces even, the styrene "main" rails keep them aligned to the ground (the two interleaved rails push the wheels against the flat surface, the two side rails keep them aligned).

At this point I inserted and glued the hull in place, reinforcing with cyano glue.

Et voilà, after breaking the gig and extracting the hull you can see the yellow wheel spacers still in place.
They are cut-to-size layers of Post-it stickers (the number of sheets gives the right spacing, about 0.36mm). They stick in place 'cause.... well that's obvious! Notice that Zimmerit appeared overnight!

Now, the gig ensures that the wheels are well aligned in a row, but the two rows are not aligned reciprocally if the hull is twisted. I marked with a green marker the wheels bottoms then sanded lightly over an abrasive planar base until seeing all of the green marks touched a bit by the sanding operation. Now the wheelbase is flat with the terrain.

The hubs are explanted from the Dragon rims and transplanted. Difficult/scary++ operation...

...but the result is nice indeed (at least I think so!)

The sprockets had the rims hollowed out; I also reduced the hub diameter, so that I had to modify the cone of the lower part; this was quickly done in a lathe. The hollowed rims will give a great improvement to the realism of the finished model.

Installing the return rollers.
Again Post-it spacers and caliper measurements help to place the rollers in the correct reciprocal positions

The model today: lower and upper hull are cemented together, and the driver compartment has been modified.

The lower hull has been pre-painted with dark yellow.

The hull is now modified with the correct slope of the compartment on the right front of the hull: I sawed away a wedge of it, pressed down the front part, glued then puttyed and sanded it plain. Now it has a correct slope and the protruding front armor plate.

The rear side, waiting for more details. I corrected the thickness of the rear armor plate, hence the white stripe filling the original separation mark.

At this point I'll start with the final detailing phase, then paint will follow, then tracks will be installed, then the weathering process... I hope to get there soon, but it will be difficult... baby cries at the horizon!

Post Scriptum
1. The escape hatch was something I was not aware of at the beginning, I hated that strange, circular "sink mark" in the lower hull and I removed it! Later I understood it is an escape hatch! As I was trying to explain, I do lot of stupid things at the beginning of my projects... I did not try to restore it 'cause it's almost invisible down there.

2. Craig Ellis is selling a modified driver's compartment and mantlet which is probably more accurate than mine, and is an easy swap with Dragon part.

3. About the Zimmerit, I used a fairly exotic technique. it's a photosensitive cement applied with an odd spatula-tool of mine, and is about 0.08mm thick... I tried this method for a full month before even starting with the model.

4. About the roadwheels: after looking at pics of the real thing I noticed that the Revell hubs are too thin; actually the entire rim is quite shallow, while Dragon's is much better. I choose a compromise in accuracy, while the best way to have a correct roadwheel would be reducing the diameter(s) of the Dragon parts. Anyway it's just a matter of personal preference; in the past months I've appreciated the beautiful Stug of Alex Clark in which a masterful use of lights/shadows gives the Revell rims much more a 3D look than they actually have!