Monday, 13 January 2014

Scratchbuilding a US M2 Medium Tank in 28mm Part 6

Picture 29 Hull Details:  While the track assemblies dried (Don’t rush them—when in doubt give it overnight to dry.) I was adding details to the hulls and turrets.  Here plastic strips add detail to the glacis, rear deck and machinegun turrets. Some thin sheet forms the side and top crew compartment doors.

Picture 30 Hull and Tracks:  Here a hull awaits attachment of the suspension units.

Picture 31 Tubes and Cylinders Two:  But first some more do-dads: the transmission covers and return wheel supports.  Thicker plastic can be built up by laminating thinner sheet.  Thicker ends on tubes can be sanded to create curve or domed tube-ends or caps.

Picture 32 Suspension Details:  A closer look at building complex looking parts out of basic shapes and layers.

Picture 33 Mounting the Tracks:  The tracks are then mounted with a transmission bit at the front and return wheel support at the back.

Picture 34 Mantlet:  A thick block of laminated plastic was carved into the shape of the mantlet.  This was then pushed into a ball of green stuff.  The original was pulled out before the green stuff dried.  Lower right is the plastic original, and lower left the green stuff mould.  When cured, the interior of the green stuff mould was wetted down with some water and ‘squashed onto a blob of fresh mixed green stuff. The two paint jars each have a formed mantlet.  Originally a squash mould was planned for the bogies, but the technique does not provide of a lot of detail.  Latex moulds are sufficient for the Alumilite.  RTV moulds would probably be a better quality option but are more expensive.

Picture 35 On Tracks:  The two tanks are shaping up nicely.  The mantlets were trimmed, sanded and installed.  Some brass rod will be used for the guns and machineguns. 

Scratchbuilding a US M2 Medium Tank in 28mm Part8

Picture 38 Adding a Tank Commander:  As you have seen the project evolved as it went along.  About this point I had ordered some Old Glory WW1 Americans for the force, and decided one of the vehicles needed a tank commander.  I made new hatch for the one turret and began to cut open the door.

Picture 38A Adding a Tank Commander:  The commander will be this prone OG loader.

Picture 38B Adding a Tank Commander:  The figure has been cut in half and a brass wire support rod added.  The hatchway to the turret has been trimmed and a new hatch door added.  A couple of gizmos from the parts box dress it up.  A tube spacer has been added in the turret to support the figure.

Picture 38C Adding a Tank Commander:  Some tools and bits from the spare parts box and some green stuff add some stowage to the tops of the tanks. 

Picture 38D Adding a Tank Commander:  The tank commander had his rear-end re-built with green stuff and some belt work added.

Scratchbuilding a US M2 Medium Tank in 28mm Part 7

Picture 36 Box of Details:  Here is a box of detail bits.  The small squares are the hatches for around the turret. A piece of thin plastic rod will be used for the hinges, and slightly thicker rod for the hinges on the doors.  The stepped tubes are layered Evergreen and are for the exhaust, as are the curved sprue bits from an old plastic kit.  Capped-tube domes will be used for the fuel caps and headlamps.

Picture 37 Adding Details:  Details added to the essentially finished models.  Brass paper clips formed the bars over the headlamps.

Picture 37A Adding Details:  Notice four machineguns (plus the main and co-ax) on the front and three outback.  I am not sure of the motion of the machine gun turrets, but I suspect they would allow an overlap of the two machineguns out each side.
I am also not sure who in the crew would operate each gun.  I suspect the front guns were fixed, likely fired by the driver and that it would not be possible to fire all the guns at once.

Picture 37B Adding Details:  Rear details include a heavy thread tow cable and a tow hook from the spare-parts box. 

Scratchbuilding a US M2 Medium Tank in 28mm Part 5

Picture 21 Starting Suspension:  While the structures were being built, usually while the glue was drying, I gave some thought to the suspension.  Originally it was planned to phoney-up the running gear from some model tank parts.  Most of my stuff is 1/72 which is way too small for this project.  I had nothing suitable, and thought about maybe squash moulding some components.  Again following the drawings, I used some Evergreen tube to plot out some bogies.  The Evergreen tube is available in nesting sizes so thicker walled tubes can be built up.  Here a driver on the right and a bogie assembly are set out on some scrap plastic card.

Picture 22 Suspension Elements:  A star shaped drive gear was cut from plastic sheet.  These are the parts for the bogies, return wheels and drivers.

Picture 23 Bogie Details:  A block of thick plastic forms the mount and a thinner Evergreen tube makes the return roller. 

Picture 23A Bogie Details:  Further details added.  The bolt heads are Grandt Line or Tichy Train model railroad bits.  Note the green stuff to fill in the gaps.  The spokes of the bogies will be filled in with green stuff and details added to the face plate and the swing arms with thin plastic rod.

Picture 24 Alumilite Components:  A series of latex moulds were then made and parts cast out of Alumilite.  The latex brushes on in many coats and is reinforced with cheesecloth.  Shown are castings of the bogie unit and a return wheel.  Since twelve bogie units were required, two moulds were made of the bogie unit.  A simplified drive gear was also made and moulded.

Picture 25 Assembling Suspension:  Support plates for the suspension were drawn out and drilled. The backs of the Alumilite castings were also drilled.

Picture 25A Assembling Suspension:  Since I wasn’t sure how well the castings would adhere to the plastic; the drilled holes were to act as rivets when epoxy glue was used to assemble the components. The back view of the suspension plates shows the epoxy “rivets”.

Picture 26 Suspension Left and Right:  The assembled suspension sides cut apart.  Make sure you have left and right sides.  There were a lot of air bubbles in the Alumilite parts.  Some filler and some terrain-mud will resolve any issues.

Picture 27 Trackwork:  The suspension plates were then trimmed to size and sanded for the curves.  The plates will also be trimmed to show track sag over the return rollers.

Picture 27A Trackwork:  Evergreen strip plastic was formed over the track side plates.  The liquid solvent glue holds the strip to the side plate.  A bit of Crazy Glue bonded the track strip to the bogies.  Liberal use of masking tape strips hold the strip in place until the glue dries.

Picture 27B Trackwork:  Inside view.  Note reinforcement strips top and bottom to hold the track strip in place.  Spacer blocks will hold the track assembly to the lower hull.

Picture 27C Trackwork:  Two assembled track units.  At this point I was looking at many, many hours gluing many, many small strips of plastic to create the track links.  Staring forlornly at my stock plastic box I came up with an alternative. (Remember that part about the only person you have to please is yourself and personal choices about how much work you want to do and how much detail you want to add?)

Picture 28 Track Details:  I had some formed plastic roof tiles that had a suitable “bump” for the track links.

Monday, 6 January 2014

Scratchbuilding a US M2 Medium Tank in 28mm Part 4

Picture 15 Planning Turrets:  The basic octagonal box structure was repeated for two turrets.  Note the top panel of the turret is sloped down at the front so top and bottom of the turrets are not identical.  This is structure, so thick plastic again.

Picture 16 Assembling Turrets:  Assembling the turrets.  Note the spacer to establish the height of the turret and that the front spacer slopes down to the front.

Picture 17 Plating Turrets:  Thinner plastic card is used to skin the turrets.

Picture 18 Basic Turrets:  The basic turrets.  A thicker plastic sheet will be used for the front plate of the turret.

Picture 19 Tubes and Cylinders:  A second structural element is round-section tubes.  Four machine gun turrets are required on each vehicle.  Here, suitable diameter Evergreen tube is capped with thin sheet.  When thoroughly dry, the cap can be trimmed and sanded to match the outside diameter of the tube.  The tube is cut to length and the open end capped, trimmed and sanded.  The capped tubes are then sliced vertically into halves.

Picture 20 Taking Shape:  The machine gun turrets are added to the crew compartment.  A plastic tube was added to the turrets to form a pivot.  Also added was a disk to the bottom of the turret to allow it to turn freely.  Some small similar thickness spacers were later added to the bottom of the turrets to eliminate wobble.  The upside down turret has a thick front plate added and has yet to be trimmed.  Note how the hull’s base plate will form the front fenders and rides above the area the tracks will run.

Picture 20A Taking Shape:  Top and rear view of the basic structures.  At this point, other than the tubes for the machine guns, there have been no curved structures.  This complex shape is built up with layers of flat sheet. 

Scratchbuilding a US M2 Medium Tank in 28mm Part 3

Picture 8 Drivers Compartment:  Here we start fitting some of the skins for the driver’s compartment. The front section forms a pyramid structure. Two sets of drawings I had did not match and one showed a “cheater” plate to fill the driver’s compartment and the crew compartment. Notice how the back of angular plate, the side plate of the driver’s compartment, does not meet with the line on the crew compartment.

Picture 8A Drivers Compartment:  This becomes more apparent when skinning in the upper sides of the driver’s compartment and the purpose of the “cheater” plate becomes apparent.  Note the gap between the upper and lower plates of the driver’s compartment.   The lowest glacis plate is also installed and can be trimmed to size and edges filed to shape.

Picture 9 Cheater Plate:  The “cheater” in blue, fills this area.  This is not obvious in the drawings, but is clearly visible on photos of the real vehicle.  The pyramid structure of the driver’s compartment is not true pyramid.  In this case, as the model progresses, the model itself will direct how it is to be built.  Note too that overlapping plates can be installed on the inner edges, and the overlaps can later be trimmed to size.

Picture 10 Lower Rear:  The lower rear, showing the floor plate. Note the lower rear is actually two plates so the side plates and rear base plate need to be trimmed.

Picture 11 Trimming the Rear Deck:  Here a razor saw aligned with the trimmed lower side plates will be used to bob the vehicle’s rear end to the correct angle.

Picture 12 Filling in Rear Deck:  The upper rear decked in.  Note the use of thick and thin for structure and for sizing.  You sometimes have to recess one part to set in an additional panel or make a part out of thicker stock to come up to the correct measurements.  Generally structure is thicker than ‘skin’.  The rears of the upper and lower sections are now at the correct angle.  The lower side plates are yet to be trimmed to the correct angle for the lowest rear plate.

Picture 13 Basic Hulls:  The “basic” hulls.

Picture 14 Basic Hulls:  Side and rear of two basic hulls.

Picture 14A Basic Hulls:  Here I took my Dremel to the floor and up thru the base plate.  I had planned to add some weight to the models.  This also gave access to the interior structure if required later.  Ultimately neither the weight nor the access was used. 

Friday, 3 January 2014

Scratchbuilding a US M2 Medium Tank in 28mm Part 2

For the M2 model the plane just above the tracks is a good starting point.  I began with a rectangle of plastic the width of the model but longer than that required.  I will build the tank’s upper works on top of this plate, and the lower works on the bottom of this plate.  This plate forms the foundation of the model, so make it out of heavy stock, in this case, 40 thou sheet.

Picture 1 Starting Point:   Shows the base plate. It is probably as easy to build two models as to build one, so construction was started on two vehicles.  Also shown here is the upper deck.
The upper deck was scaled off the drawings and drawn out straight onto the plastic sheet. Since the turret will mount on this deck, it and the spacers supporting it, were cut from the heavier 40 thou sheet.

Picture 1A Turret Deck:  This shows the upper deck plate. Note the arrow and the correction in the upper right corner.   While the basic rule is measure twice, cut once, most things can be corrected as the project moves along.

Picture 2 Assembly One:    Shows a “front view” of the basic assembly.  I use Testors liquid Plastic Cement for the styrene parts.  The forward part of the base plate is much longer than required; it will be trimmed in following steps.

Picture 3 Plans on Materials:   Since we have scale drawings, parts can be measured on the drawings and transferred to your stock.  This is the left and right sides for the rear of the vehicles and since this is ‘skin’ and not structure, it is lighter 20 thou plastic card.  Two vehicles: so two lefts and two rights, two ups and two downs, as the depth of the rear structure is not half way!  Keep your left/right and up down spacing correct.  Laying them out as a group ensures equal measurements.  Note the double line where a measurement was checked and corrected.  The trick then is to remember which line to cut.  If a piece is miss cut, it is usually best to discard it and cut again, rather than fiddling to fix it.

Picture 4 Side Plates:  Here we start to “skin” in the upper structure.  The ‘octagonal’ crew compartment is skinned in and the side panels are mounted.  Note the reinforcement bit on the upper right.  Try to get a tight corner along the edge of the base plate.  Notice too, the side plate sits on top of the base plate but the top plate is inside the side bit.  Basically the purpose of the base plate is also to preserve the dimensions of the vehicle, providing a straight line from the front fenders to the side plates.

Picture 5 Lower Hull:  Here, side plates for the lower hull are sketched out.  These side plates will support the tracks so they are also heavy stock.

Picture 6 Lower Hull Two:  The model itself forms part of your building plans.  The underside of the base plate is marked for a centre line and the position of the lower side plates.  A line across the vehicle marks the rear edge of the crew compartment and references measurements front to back.

Picture 7 Lower Hull Three:  This photo shows the lower hull plates assembled with a rectangular lower plate.  Also installed is a lower glacis plate, and part of the “pyramid”.  Using a top view of the drawing the width of the pyramid plate at the upper glacis can be determined. The length of the angled plate can be taken from a side view of the vehicle. -At this point, you are into the world of ‘as-builts” if your model is not to the scale or size you want, it is probably best to start over before you do too much work.  Otherwise, use the model to determine the dimensions of the parts.  It is as you built it.  The width of the front glacis is the width measured on the model.  What I have done here is trim the front portion of the base plate to leave the front fenders sticking out. I then trim the plate to allow the front glacis to assume its natural angle.  It will be very close to the drawing and it’s up to you how close you need it to be.  For me, this is close enough.