Building a Small Scale BAT-M

Douglas Bauer

One of a long line of purpose-built engineering vehicles, the BAT-M was produced by the Soviet Army in the 1960s, and was primarily used for road-clearing and excavation. Its electro-hydraulically operated plow could move up to 200 cubic meters of earth per hour, and could be placed in a travelling position over the rear of the vehicle.The BAT-M was also equipped with a rotating crane and a hydraulic winch which aided in vehicle maintenance and retrieval. The T-55 chassis is used as a basis for the vehicle, with a modified truck cab for the driving and crew compartment. The BAT-M usually carried no armament, except for personal weapons carried by crewmembers. It had a filtration system which allowed it to operate in contaminated areas for short periods of time. The two-man crew could place the vehicle into operation in 5 - 7 minutes. After several years’ service the BAT-M was replaced by the BAT-2.

Technical data:

Chassis: AT-T tracked heavy artillery tractor

Weight: 27.5 metric tons

Crane capacity: 2 tons

Winch capacity: 25,000kg

Top speed: 35 kph

Range: 500 km

I first saw this unusual vehicle while browsing through Henrik Claussen’s website. I’ve always been interested in rare and unusual armored and soft-skin vehicles and I asked Henrik if he could send me some more photos of the BAT-M. After receiving the photos I enlarged them and printed them out in color. After careful study of the prints, in order to determine a logical construction sequence, I was ready to begin the project. I had decided in advance to model the vehicle in 1:72 scale. The model was constructed using styrene sheet, rod, tubing, and strip. Gap-filling CA glue and Weld-On #4 were used for joining surfaces and applying detail parts. I found that using gap-filling CA with a kicker greatly reduced drying times when filling seams and forming curves. Just be sure to file and sand it within an hour of its application, as it will quickly become rock-hard and resistant to sanding. One of the most difficult phases of the project was shaping the compound curves of the truck cab, but it was mostly time-consuming filling and sanding. A lot of folks use Grandt Line nuts and bolts for detailing, but I prefer another product: Plastruct manufactures hexagonal styrene rod, which, when wafered with a sharp hobby knife, will produce a perfect hexhead bolt. The rod can be found in sizes from 1/8" to as small as .020", I was initially using wafered round stock for boltheads, but even in 1:72 scale hexhead bolts add a lot more realism to a model. When attempting a scratchbuilding project such as this it is a tremendous time (and sanity-) saver to have some knowledge of resin casting techniques, and there are a lot of articles on the subject in modeling publications and on the Internet. The ability to cast such items as road wheels, sprockets, track links, etc., will speed up your work and eliminate the tedious chore of making all the road wheels separately.

In order to have something with which to gauge my measurements I purchased the ESCI T-55 kit in 1:35 scale; from this model I took my chassis measurements and scaled them down appropriately - for ease and simplicity I merely halved the 1:35 measurement, then subtracted about 0.5mm or so to reach 1:72. For me, that’s one of the plusses of modeling in small scale: although I do strive for accuracy, in such a small scale 0.5 to 1.0 millimeters either way doesn’t really make that much difference in the end result.

CONSTRUCTION

Chassis and running gear

Once the dimensions were obtained and scaled down I cut the basic chassis shape out of .030" sheet styrene - you can use sheet of this thickness because the cut edges will not be showing, and the thickness adds strength to the body. I scaled-down a road wheel, sprocket, and idler wheel set from the ESCI T-55 kit and produced a styrene master for each assembly. [Batm_3] Because I’d be casting 20 road wheels, I made three molds to ensure the quality of the castings (each use will cause the RTV mold to lose a little of its elasticity and dry out - and with smallscale I seldom use a barrier coat). Once a pair of road wheels had been cast and cleaned up and temporarily glued together I could use it as a gauge to determine the proper width of the fenders. For my model I made a resin casting of some ESCI T-62 hard plastic tracks - but you can use the plastic ones if you want. I placed a section of track atop the wheels and measured the distance from the side of the hull to the outside of the track...then added two millimeters to allow for error, and this was the width of the fenders. This is a critical measurement, for nothing is worse than scratchbuilding a model, only to find the tracks won’t fit. Having all the road wheel sets will also allow you to determine the proper spacing for the wheels, plus the drive sprocket and idler. I then prepared scaled-down versions of the suspension swing arms, but didn’t glue them into place yet - I knew I’d only end up breaking them off during construction.

cab

Then it was time to tackle the cab. I wanted to detail the inside of the cab, so I used my imagination and the realization that it would be difficult to see much of the interior in the first place...that made things considerably easier. A bench seat, some instrumentation, steering controls, and hydraulic levers were added to a floor plate which fit inside the cab walls. I didn’t glue the floor to the cab yet because there would be considerable sanding and shaping to get the cab contours right. The cab was assembled using .030" sheet - again, for strength. A triangular piece of solid styrene was placed along every joint - this provided the extra plastic that would be needed to bolster the joint when shaping began.

Use CA glue for this operation. Another way to do this would be to apply a thick bead of CA glue along the joint and spray it with accelerator...either way, the result will be the same. Next I filed and sanded the compound curves of the cab, checking constantly for symmetry. Once the correct shape had been achieved, I used a Dremel tool with a cutter to curve the triangular plastic braces (or the CA bead) on the insides of the joints. If you don’t plan on modeling the doors open, this step can be omitted. The doors are simply a three-piece lamination, sanded to produce the proper shape. I used .010" rod to detail the hood, and for the rain gutters above the doors. Quarter-round was used to simulate the expanded metal cooling slats on the sides of the engine compartment. I simply cut an appropriate number of equal-sized pieces, gently tapered off the ends and glued them to the sides of the engine compartment - rounded side facing front. The grill was cut and filled with vertical .020" slats. Lights and light guards, grab rails, windshield wipers, and door hardware can be added later, but be sure to add the clear windows or you’ll certainly struggle to install them with the cab glued to the deck.

Hydraulic crane and hydraulic rams

The next assembly was the hydraulic crane. Basically a hollow, tapered, and angled beam, I drilled out some evenly-spaced lightening holes, making sure they matched those on the other side.

It’s a good idea before gluing the crane together to paint the insides flat black, so the white styrene won’t show through the holes once it’s been assembled. The winch motor and take-up reel, and wire fairleads were added next. The rotating base of the crane is a tapered cylinder formed by using telescoping plastic tubing, the edges filled with CA glue and sanded to shape. After determining the proper angle for the crane, and, using a small hydraulic ram, I marked the placement for the ram attachment points. A word about the rams: you’ll need to make six for the dozerblade, and one for the crane. Let’s stop for a moment and discuss their construction: care must be taken to ensure that all the hydraulic rams and their cylinders are of equal length, to avoid tears and heartache when it comes time to put this all together. It may seem tedious, but I assembled the rams as they are in real life – in this case, styrene tubing is cut to the proper length and capped on both ends with a plastic wafer; then a hole is drilled in one endcap and the piston placed inside the cylinder…in this way, minor adjustments can be made.

Needless to say, a lot of dry-fitting throughout the project is in order. I recommend using a good quality liquid glue for final assembly of these low-tolerance parts, as it will give you the opportunity to make those minor adjustments. If extra strength is desired later, one can apply thin CA to the joint and let capillary action draw the glue to the spot. Each ram needs two hydraulic lines - a supply line and a return, one at each end of the cylinder. For the fittings I used .045" rod: I drilled a small hole in one end to accept the .022" solder wire (from Radio Shack) hydraulic line.

The lengths of the lines will depend on the placement of the rams - more on that later – just make sure you have enough. Since I had no idea where the hydraulic pump was located, I stuffed the ends of the hydraulic lines under the fluid tanks. Once painted, the Bare-Metal Foil can be added to the end of the piston...a nearly-impossible task once they’ve been glued to the model.

As with other models consisting of many different sub-assemblies it is probably best to paint each assembly as it’s completed. As far as weathering goes, with a model of this genre it might be easier to weather as you go - my preference is to weather with pastel chalks instead of washes. It’s much easier to control the weathering effects and "blend" the assemblies together. I guess it’s purely a matter of personal preference. My technique is to paint the model in the basic color (I used Testor’s Russian Armor Green enamel)...in this case, since the paint is a semi-gloss, I had to spray a coat of Testor’s Dullcote to provide a surface for the pastels to adhere to. Once the Dullcote is dry, grind up some black or very dark brown pastel chalks on a piece of sandpaper; then, using an old #2 filbert brush apply the chalk to all the corners and joints, around detail parts, and everywhere you’d want an oil wash to collect. You’ll want to apply it rather heavily, because once you hit it with the Dullcote sealing coat, the air from the airbrush will blow some of the chalks off the model. Once that’s dried sufficiently you can drybrush as usual.

Dozer blade

The dozer blade is merely heat-curved .030" sheet, and the supports are forms shaped with more .030" sheet. Using thick plastic allows one to round off corners without sacrificing strength. The photographs show various views of the blade and its supports, plus attachment points for the hydraulic rams. [Batm_7] [Batm_8] The three-part blade was glued onto the supports, then re-inforcing gussets were added. Again, careful measurements and dry-fitting are imperative. Once completed, it was painted it and placed it aside...it was the last thing added.

accessories

Now the two hydraulic fluid tanks and their supports were constructed, with their associated plumbing. The tool boxes were constructed of solid styrene pieces with thin plastic lids. Don’t forget the typical Russian re-inforcing ribs on the lids. Don’t glue the toolboxes in place until you’ve determined exactly where the ram attachment points will be. I placed a scratchbuilt dozerblade depth minder on the deck, plus assorted cables, chains, wooden blocks, and tools. I even added a tiny cutting torch, made from styrene tubing and thin solder for the oxygen and acetylene leads. Observe the fairlead on the left of the crane base: a wire leads out of a rear-mounted winch (under the chassis, out of sight, so you need not make one), through the fairlead and is attached to the left of the blade support. Heaving around on the wire would help raise the blade into the travelling position, where it rested on two sturdy posts.

Final assembly

Once all the sub-assemblies were completed, painted and thoroughly dry, it was time for final assembly. The road wheel halves were glued together – I CA’d a thin styrene wafer between the two wheels…this allowed me to make sure the wheels were even when liquid-glued together (using CA to glue the resin wheels together would’ve given me precious little time to ensure their evenness). Next I CA’d another small styrene wafer to the hub of the inside wheel…this would allow me to make adjustments when I glued the wheels to the styrene suspension swing arms. Once the swing arms and wheel assemblies had dried, I was able to liquid-glue them to the sides of the hull – paying careful attention to the spacing. The drive sprockets and idlers were saved for later. When I was satisfied that they were properly spaced and the model sat evenly on the wheels, I set the chassis aside to dry thoroughly. The next day I prepared the tracks – I had previously cast several sections of track from my RTV mold, painted them with Floquil’s Rail Brown, and weathered them (for added realism, superglue some small triangular guide horns on the individual links..it’s not necessary to do each one, maybe every other one – and don’t forget to dull silver highlight the worn areas). After supergluing a piece of round stock to the centers of each sprocket and idler to act as an axle and drilling a corresponding hole in the chassis, I prepared them for the tracks. Since the track links wouldn’t fit around the sprocket, it was necessary to file away several teeth…an arc of about 160 degrees. Now I glued the separate links around the sprockets and idlers, and when dry I touched up the whole assembly with paint. The top and bottom track runs were superglued in place, and their ends mated with the ends on the sprockets and idlers. In retrospect, I think I might better have used an epoxy cement for this step, as it would have given me a lot more time to ensure proper placement of the track pieces. Needless to say, this step can be very exasperating, but patience and planning will win the day.

Now the cab was glued to the chassis….then the hydraulic fluid reservoirs were attached. The pre-assembled crane was centered on the rear of the chassis and glued into place. I used low-tack masking tape to secure the chassis and the dozerblade in place while I positioned the hydraulic rams – don’t drink a lot of coffee before attempting this step, you’ll need a steady hand!! - I also marked on the chassis and dozerblade where the ram attachment points would be . The styrene attachments were then CA’d to their respective positions and the rams attached to them with liquid glue. I took a break and walked around the room, then returned and closely eyeballed the entire model, looking for symmetry and evenness, adjusting as needed. I let it set for about an hour then checked it again; when I was satisfied I touched each attachment point with a drop of thin CA to strengthen the joint. This part of construction is pretty much a matter of what works best for you. Another modeler may find a better way to do it (and I hope he does), so feel free to experiment. Windshield wipers, loading light, taillights, and headlights and guards were added last.

The base

I found trophy shops to be good sources for smallscale model bases. They have a wide selection of wood or simulated wood finishes, as well as solid colors – and the best part is, they’re ready-to-use. For the BAT-M I used a plaque that had a rough texture to it, because I knew I’d be using Celluclay and I wanted a surface it would easily adhere to. I slathered on the papier-mache in an appropriate thickness, then, using an imitation dozerblade made from scrap plastic I made the blade’s track through the "earth". Once that was done I took a piece of track and made impressions in the groundwork…don’t forget to make small grooves in the smoothed earth behind the blade to simulate where rocks have scratched the surface (not critical, but adds an extra touch of realism). I then painted this area of the still-wet groundwork with a dark brown acrylic. Next I placed the model into (notice I said "into" and not "on") the groundwork…this vehicle went through the terrain, not over it! To make sure the model stayed put on the base I added a bead of white glue under the tracks; then, using the blunt end of a paintbrush I pushed the tracks well down into the Celluclay, giving the impression of great weight. When the Celluclay had dried I added more of the stuff mixed with "Static Grass" along the path of the dozerblade and in front of it…I also put random clods of "earth" around the tracks as well. Once dried, this was also painted with a dark brown acrylic, and drybrushed with earth tones, and an occasional touch of green on the grass. "Static Grass" was also spread on the remaining groundwork and finished appropriately.

I spent over 100 hours on this project, which was made so much easier because I had access to well-detailed photographs; but like any model of a rare or unusual vehicle, a certain amount of educated "gizmology" is required, and the BAT-M was no exception. For pure enjoyment and a true test of your modeling skills, I would encourage everyone to experience the challenge of smallscale scratchbuilding.