BP Models

Build log for DML kit #6460 SdKfz 166 Stu.Pz. IV "Brummbar" Mid Production with Atak zimmerit and MK workable tracks.

A new project means starting at the beginning...so as you would expect with a Dragon Pz IV kit, Step 1 meant spending a lot of time on the sprockets, idlers, return rollers, and road wheels. I found a reference pic of one of the 3 vehicles the kit markings provide for, the Command version #1, and used that as a guide to decide on the style of idlers and return rollers. All of the road wheel halves had their mold seams sanded away with a sanding stick but left unassembled to make it easier to paint them later on.

I also assembled a short run of 8 links of the MK set to double-check the spacing on the sprockets, idlers, and return rollers to make sure everything would play nice later on as well.





Step 2 deals with the rear hull plate and I installed that to the lower hull first and then added the details to avoid issues with stuff getting in the way of a good join. Some light sanding at the base of the plate was all that was required to get a good fit with the weld seam line there. The Atak zim panels for the rear were added using Gator Grip glue and regular liquid glue around the edges to tack things down where needed. I opted for the heavy-duty towing hitch since that was a regular feature on Pz IV chassis at the time the Mid version of Brummbar's were built.



Step 3 deals with the hull front and the addition of the final drive front base plates. It's a good idea to install the nose plate first and then add the final drive plates after as they are a tight fit due to the small bolt detail on the one side of the drive plates. The tow points were added and the pins needed some trimming to fit correctly in the openings. Once that was set, I added the bolt-on armor plate for the nose underside from Step 6 and the installed the zim panels. Some slight putty work was needed between the joins on the two plate panels, easily taken care of with some Squadron White putty and a little sanding.



Next up will be the suspension and lower hull sides.

Continuing on from last week, this week's efforts focused on the lower hull and suspension.

Step 4 adds the base mounts for the suspension along with the bump stops and the rear towing hooks. The Atak panels for the lower hull are provided as a large single piece and some trimming was necessary here and there to get things to fit properly but otherwise no major issues were encountered. From experience, I know that the front piece that curves over the final drive will interfere with the fenders when it comes time to install so I cut that short on purpose to head off that issue.





Step 5 returns to the hull rear and adds the idler mounts and the exhaust. The instructions provide a choice of type of idler mount and after checking reference photos I went with the parts B15/14 as those are the later style appropriate for this vehicle's production time line. The multi-part muffler was assembled and the exhaust pipe thinned out with a drill bit and some trimming with the tip of a sharp #11 blade. I had to trim the Atak panels a bit more to allow the pipe support trays to fit correctly in this area as well.



Step 6 installs the hull glacis plate and the Atak set includes a resin replacement with separate parts for the transmission/brake access hatches. Those were added using CA gel and the narrow panel for the full front plate zim added along with a little putty to round things out in that department. The glacis spare track run will get installed later after the hull is painted to make it easier to detail it at that stage.



Step 6 also calls for the road wheels and suspension elements to be installed. The road wheels were left off for now but the suspension elements were added. They have just a little bit of play to them so it's important to get them all lined up correctly so that the vehicle will sit level later on.



That brought me to Step 7 which deals with the assembly of the fenders and their installation to the hull. I added the front mud flaps first along with their zim panels, carefully trimming them to avoid the interference problem mentioned previously with the lower hull sides. The kit designers didn't build in any tolerance levels for zim interaction in these areas so the added fractional mm that the zim creates causes issues if not dealt with accordingly.

The fenders were then installed using regular glue along the hull edges where they overlap and liquid glue at the rear where they sit flush. After that had set up, I added the rear mud flaps and finally the spacer parts between the schurzen mounts. The spacer parts don't have a large surface area that they attach to so it made sense to install them after the fenders were in place to avoid them coming loose or getting skewed accidentally during the fender installation. I also did a test fit with the casemate to be sure everything was playing nice at this stage.



Next up will be the upper hull elements!

My wife had a school event this evening so I was left home alone...and decided to sneak in a little extra bench time to take advantage of the situation!

Step 8 is a prep step that assembles the side air intakes and the rear engine deck top as well as the rear plate...and then puts them all off to the side until Step 17. There's no real reason to wait that long so I went ahead and assembled the rear hull and installed it into the lower hull. The Atak set includes a replacement rear hull plate but it doesn't have the spare wheel holder parts attached to it, so those will have to be transplanted from the DML kit part later on. It's also important to note that in Step 8 the diagram isn't very clear in how the step plate over the muffler/exhaust installs...it has three L-shaped support arms that install to the back of the plate and support the plate over the exhaust. The Atak side panels were added as well at this point.



The installation into the hull in Step 17 includes the install of the rear bulkhead, the tread plate floor for the fighting compartment, and the gun mount base. The base is a 4 part affair that has to be assembled just so or it won't be possible to fit it into the hull in the correct position. You cannot assemble it outside the hull as the diagrams indicate and then install it as one piece into the hull. This is due to the way the two side supports interact with the hull...they have slots in their sides to fit into the angled "ribs" molded into the lower hull and also slots on their feet that match up with tabs on the hull floor. You have to install these first, then position the top part, D7, within the hull at a slight angle to clear the fender edges, then turn D7 to sit properly and flush on the side feet. The front support should be glued to D7 prior to doing this. It took me a couple of different attempts to figure this out, hence the glue marks on the hull floor you see in the photo.



The interior tread plate part, D6, should then install into position between the rear bulkhead and the gun mount. A test fit showed this was no problem and while my back was turned to take the photo above, my beloved boxer Brenda somehow managed to get hold of the plate. She only had it for a few seconds but the damage was done as she's a "power chewer"!



It's not a big loss as I wasn't planning to display the hatches open for the interior and this sealed it for sure if I did have any doubts otherwise!

Next up will be working on the 15cm gun assembly.

This weekend's round of bench time was very productive and work continued on the gun and superstructure. I decided to build the gun first as it's designed to go into a static mount in the fighting compartment and everything else revolves around it as a result in terms of fit and placement.

That meant skipping to Step 11 which assembles the gun and breech as well as the collar and recoil cylinders. The breech block can be left movable if you so desire and some sanding is necessary on the join halves of the breech but otherwise it's a straightforward step.



Step 12 combines the elements from the previous step and adds the recoil guards. Step 13 assembles part of the gunner's side of the gun mount by adding a choice of two different styles of traverse gears. I chose the simpler type for expediency.



Step 14 completes the gunner's side of the mount with the addition of the gunner's seat, the gun sight, and the elevation wheel. There's also a toothed gear that is added that the instructions indicate shouldn't be glued...I tried this out and found it to be unnecessary to allow the gun to elevate and omitted it since I'm closing up the interior anyhow. I suppose if you were really really careful with the glue you could find a way to make the gear actually "turn" with the gun as it elevates but it's not essential to the gun assembly in the long run.



Step 15 is the moment of truth, it adds all of the previous components together along with the base and ball mantlet to create the full gun assembly. The fit on E19, the ball mantlet, was too tight for the gun barrel to slide through so I had to trim and sand it with a round needle file on it's inside diameter to get the gun barrel to fit. Even then it was an extremely tight friction fit and a challenge to get it to slide all the way down. It also has to fit tightly over the side hinge points of the gun mount and the fit has to be just so for it all to work. I got it as far down onto the mount as I could make it go but I suspect that it needed to go about another 1mm or so to actually fit correctly. Unfortunately the friction fit made it impossible for me to remove it and try again...and this in turn resulted in some issues down the road in the following steps.



I added the interior plate from Step 9 and did a test fit with the gun mount dry-fit in place and sure enough, the mantlet interfered with the fit, causing the rear of the superstructure to not align properly with the fenders and engine deck...a major problem. This meant that the interior ring around the ball mount needed to be trimmed back to allow the mantlet to clear it. This was done with careful trial-and-error and much trimming and sanding.



This led me to wonder if the same issue might be encountered with the exterior circular plate, so I added the Atak zim panels and resin plate and did a test fit. It too had the same issue, so same trimming and sanding treatment was called for. I also used some Squadron White putty thinned with liquid cement to fill small gaps around the circular plate and create a unified look with the rest of the zim panels.



I decided to go ahead and zim the rest of the superstructure before installing it to the hull to make sure I didn't run into any more fit issues. I decided that I would not mount the schurzen rails and opted instead for just the small mount tabs as called out in Step 21. The tabs were installed first and the zim panels added after followed by the lifting hooks and pistol ports from Step 9. Small amounts of trimming were needed here and there and lots of test fits with the lower hull, so I'm glad I decided to zim first. I also opted for the command version "adler's nest" 2nd antenna mount and added that from Step 18.



With all that out of the way, it was time to install the superstructure to the lower hull. I used a combination of regular glue, liquid glue, rubber bands, and finger pressure to get a good join all around.



Next up will be the roof and small details and then I'll start in on the tracks.

The Memorial Day weekend just happens to coincide with the completion of my latest MBA class so in celebration I'm posting an update a day earlier than usual because this is as far as I'm going to get this weekend!

Work continued on the fighting compartment roof as called out in Step 10. All of the hatches were installed in the closed position with the exception of the commander's "rabbit ears" scope hatch. I installed the base for the scope to the roof plate and will add the scope itself later after painting since a test fit revealed I could easily install it through the opening without problems. The plate was attached to the vehicle first and then the hatches and details added to avoid any complications with the fit. The gunner's sight and the driver's periscopes were masked with small amounts of blue tack putty to keep their faces clear during painting and small amounts of Steel painted on their rear faces to provide a little reflective color.

I also paid a little more attention to the ball mount collar...I wasn't 100% satisfied with the fit/gap look around the edge so I used some of the thin resin carrier film from the Atak set and some CA gel to add some strips around the curved portion to tighten things up a bit. Careful trimming with the tip of a #11 blade removed the excess and a little bit of sanding to make sure it was flush was all that was needed to improve it to my satisfaction.



With that done, it was a case of going through the various steps in the instructions and looking for details that needed to be installed before painting and cleaning up the stuff that had been temporarily skipped. I used the kit-supplied PE to add the rear superstructure scalloped braces, installed the fire extinguisher, the rear Notek light, and the rear side tool box. The antenna mounts had their bases drilled out with a #76 finger drill to prep them for the installation of brass antennae later on. I also surgically removed the spare wheel portions from the original kit rear engine deck plate and transplanted them to the Atak plate and added the rest of the mounts with CA gel.



The front fender details also received some attention. The front Bosch light was assembled and installed with some 0.5mm solder added to create the missing wiring conduit. The jack was also assembled and installed into position to round things out. The other fender tools and details will be added later after the hull base coat is applied.



The reason this is where the update stops for this weekend is due to the fact that the next step is the MK track assembly. That's a somewhat repetitive task and won't get done this weekend so there's no point in holding off as a result. Once the tracks are done it will be on to the painting stages!

Dealing with the track assembly is always a time-consuming and repetitive exercise but the payoff comes in the end in terms of flexibility with the weathering and other finishing steps, so it's worth it. The MK set assembles fairly straightforward, just a matter of removing the links from their sprues, cleaning up the attachment points, and using the supplied jig to assemble the runs. The set includes 2 jigs, so it's possible to work on two sections of 8 links at a time which allows the glue to set up on the pins and guide horns but not cause an interruption in the process. The pins come with their own handles which simply twist off while the guide horn handles need to be removed with sprue cutters and the attachment point cleaned up a bit with a sharp blade tip.



The set recommends 99-100 links for a Pz IV family vehicle but I stopped at 96 links to allow for flexibility when the time comes to install the tracks onto the suspension and will add the extra links needed at that stage. So 192 links, 192 guide horns, and 380 track pins later, the runs are done!



Next up will be painting the exterior and moving on to the remaining details.

This weekend was a productive one with a lot of progress on the paint work for the exterior. Not a lot of prep work was required except for the mounting the road wheels, sprockets, and idlers on trusty toothpick handles using blobs of blue tack poster putty. First round of airbrush work involved the application of a primer coat of Model Master enamel Italian Dark Brown. This helps check the putty work and insures there isn't any bare plastic peeking through the base coat.



Speaking of the base coat...that was applied next by airbrush using a 50-50 mix of MM enamel Panzer Dunkelgelb/Light Gray. I used multiple passes with the airbrush to slowly build up the finish instead of applying as a single heavy coat. This is particularly necessary due to the increased surface area and nooks/crannies produced by the zim application.



Next up was the camouflage pattern. Using the reference photo I dug up earlier along with the box art, I applied a brown squiggly pattern freehand using a 50-50 mix of MM enamel Military Brown and Leather. The pattern deliberately stops at roughly the height of the schurzen plates on the hull side to mimic what the reference photo shows.



Last step involved applying a mist coat from roughly 12" away from the model using a heavily thinned mix of the base coat and opening up the airbrush needle all the way to create a nice wide pattern. This toned down the camo work, fading it slightly, and tying it in nicely with the base coat as a foundation for more work later on in the weathering stages.





The road wheels, sprockets, and idlers got their due as well. They were primered at the same time as the hull and the rubber portions painted via airbrush using MM enamel Gunmetal (not the Metalizer!). The hubs on the road wheels were airbrushed using a circle template to mask the rubber tires.



Next up will be working on the exterior details and getting things ready for the weathering stages.

Spent some time working on the exterior details and getting them installed. First order of business was assembling and installing the road wheels into position on either side and the spare road wheels for the racks at the rear. Then came the tools and tow cables. The left side received the idler tensioning wrench and jack block and it's important to note here that there are 2 holes that need to be opened up on the fender to accept the block but the instructions don't call this out at any point in the assembly. I modified the block somewhat, adding in the missing woodgrain texture on the sides by scribing in some lines with the tip of a sharp #11 blade. The block was given a foundation application of the 50-50 dunkelgelb/light gray mix used for the hull followed by a thinned wash application of MM enamel Leather. Once the wash had dried, I added some Burnt Umber pastels for a bit more variation. The wrench was detailed with MM non-buffing metalizer Gunmetal and lightly dry-brushed with MM enamel Steel.

I also detailed the gunner's scope and installed the "rabbit ears" scope for the commander at this stage.



The right side didn't have much to install, just the track changing tool and the tow cables. The tool was painted the same as the wrench on the other side as were the tow cable ends. For the cables themselves, I replaced the kit-supplied steel wire since it was too stiff with crochet rope thread of a similar diameter. To prevent "fuzzing" of the thread, I dipped it in Future and let it air-dry before painting it with the MM non-buffing metalizer Gunmetal and attaching to the cable ends with CA gel. The result is a more flexible cable that could be positioned as needed. The instructions-recommended length of 115mm is about right and DOES NOT include the length of the cable ends in that calculation.



The rear hull details got some attention as well. I used Tamiya Clear Green for the Notek convoy light lenses and Clear Red for the reflector. The exhaust was detailed with a base coat of MM non-buffing metalizer Gunmetal followed by a thinned wash application of enamel Rust. I used black artist pastels on the domed pipe cover to simulate exhaust accumulation. The starter crank was detailed and installed with CA gel, the only slight modification coming in the form of removing the molded on clamp handles and replacing them with PE handles from a Griffon tool set for added detail.



I still need to work on the spare track runs for the front hull but will take care of that when I finalize the main track runs for consistency. Then it will be on to the decals and weathering stages.

Managed to get in a good bit of work on the Brummbar this weekend and have some solid progress to report as a result. First up, some "pre-weathering" attention was given to the lower hull and running gear. I stippled some MM enamel Burnt Umber to simulate scuffs and scrapes and also applied some MM metalizer non-buffing Steel to the contact surfaces on the return rollers, idlers, and sprocket teeth. I used blue-tack to dry-fit the sprockets and did a test fit of the MK track runs to see how many links I needed to add to get the sag I wanted. 99 links in total did the trick and the idlers are still movable to allow for final adjustments when the tracks are permanently installed later on.





I also worked on the hull front spare track runs. I used the kit-supplied Magic tracks for these to add some visual variety since the solid-horn type of tracks were a later type than the main track runs with their hollow guide horns. I used a #76 finger drill to open up the track pin holes on the first and last links of the larger run on the hull nose for some added detail there and the small cleat faces needed to be trimmed off to allow them to fit into the holder due to the zim pattern reducing the clearance a bit. Both track runs were given a base coat of MM non-buffing metalizer Gunmetal, lightly dry-brushed with enamel Steel, and followed by a couple of applications of a Rust wash. I added some dry-brushed enamel Burnt Umber for variety and installed them into position. I also detailed the driver's periscope while I was at it.



Those were the last remaining details needing attention, so the entire vehicle was airbrushed with Future acrylic floor polish straight out of the bottle to seal in the paint work and prep for the coming weathering stages. I applied the simple decal markings consisting of a single-digit hull number and crosses using Walther's Solvaset to get them to lay down over the zim surface. A 2nd coat of Future to seal in the decals and she's all set for the next stage of the finishing process.