Scratch-Building in 1/76 Scale
-
By Andy Lang
This article by Andy Lang was first published in Dragon, the reprinted in 1997 in Tankette, the excellent memeber magazine of MAFVA (which I think is quite indispensable for any smallscale military modeller). Now it's once more reprinted, by kind permission of Andy Lang himself. I think it's the best ever written on the subject of scratch-building small scale tanks. For those who build WW2 or modern AFV:s, the need for scratch-building decreases with the current wave of new plastic and resin kits, covering almost any subject you can think of. We WW1 modellers are not as blessed (not yet, anyhow) and this technique should be considered, not just to fill a gap in your collection, but simple because scratch-building is actually great fun! Enjoy Andy's excellent article!
PART
1 –BASIC HULL CONSTRUCTION
1. One of the
great pleasures of modelling, to my mind at least, is having an idea of what a
particular finished model will look like and then seeing it take shape. This
enjoyment takes its purest form when scratch-building a model. Rather more
prosaic reasons for building from scratch stem from the lack of a particular
model in die ranges of the various manufacturers, or from the quality of kits on
offer. I personally find small-scale
resin kits rather limiting, particularly in the moulding of suspensions &
other detail. This should not be taken as criticism of all resin manufacturers -
there are finite commercial limits to what can be done with resin moulds.
2. A point that I feel worthy of mention is that
scratch-building isn't actually more difficult than super-detailing or
converting kits - to my mind there is every bit as much skill involved in
bringing up a moderate or average kit up to standard as there is in
scratch-building. However
many experienced converters & super-detailers seem to fight shy of
scratch-building. A more obvious difference is that of timescales -you cannot
just throw together a scratch-built model in a couple
of evenings. In this series of articles I intend to outline the I basics
of 1/76 scale scratch-building, with reference to a particular modelling project.
3. If you are scratch-building for the first time,
it is worth starting off
I with a fairly
easy project, like the Russian T 60 I refer to below. (Taking on a challenging
model, like the British A9 or French Somua S 35, will probably result in your
becoming fed up and giving up scratch-building, never to return. The little T 60
is the easiest scratchbuild l have come across - the hull & turret are all
flat plates, there are only a few rivets and the suspension components can be
taken straight from a couple of 1/76 kits without modification. I will refer
to this Model at various stages in my
discussion.
4.
I will assume that you have some experience of modelling and I don't propose to
discuss tools in great detail. My
own tool outfit is pretty modest and includes a knife & straight blades,
razor saw and a few needle files - round, triangular & square section.
For heavier sanding I use a nail-file & emery boards. I find that
finishing-off is best done with fine abrasive paper and by scraping with the
side of a knife blade. A more recent addition is a small hand-held drill,
together with a selection of bits - I have 0.3, 0.5, 0.7 K 0.9mm
diameters. A metal
ruler is normally deemed to be essential, but I have always preferred the clear
plastic type as I like to be able to see the plastic card underneath. I don't
seem to cut myself very much and the main problem is that the knife blade
periodically takes a small slice out of the ruler edge, however they are pretty
cheap to replace (the ruler, I mean, not my fingers!).
5.
A word on plans is probably also appropriate at this stage.
You will be aware of the importance of having a decent plan if you have
done any amount of modelling and the various sources are fairly well known.
Don't worry if you have a perfectly good plan in the wrong scale as it can
easily be reduced or enlarged using a modern photocopier. As a guide, the scale
factor for reducing a 1/35 plan to 1/76 is 0.46. Commercial photocopiers don't
seem to be able to do this in one go, so reduce your 1/35 plan by a factor of
0.68 then repeat the process using the interim copy (0.68 x 0.68 = 0.46).
6. I always work from a photocopy of the original
plan the reason for this (quite apart from the fact that it preserves the source
material) will shortly become clear. Unless you have a 'de-luxe' plan showing a
cross-section of the hull, you will probably find that the hull outline is
obscured in places by the trackguards & other detail, but it usually isn't
too difficult to construct the true shape of the hull cross-section on the plan
by projecting onto the side elevation from the other views.
Getting Started
7. The logical starting point for a scratch-build is
the hull and the generally-accepted method of construction is to build this up
plateby-plate, with the top, bottom, glacis and rear overlapping the hull
sides. I mention this now as it is necessary to allow for the thickness of the
top, bottom (etc.) when marking-out and cutting the hull sides. A decision
should also be made at this stage about the thickness of plastic card used for
the basic construction of the hull. As a general rule, 20 thou is a good
thickness to use for most 1/76 scale subjects, although 30 thou may be necessary
for larger models such as the Russian T35. Having made this decision, prepare
your side elevation by drawing in lines parallel to the faces of the hull sides
but moved in by a distance equivalent to 20 thou (about 0.5mm). If this is not
clear, then see Fig. 2. This is the actual size & shape that you will cut
out for the hull sides.
8. Next cut some small strips of Sellotape or
masking tape and stick the plan photocopy to the sheet of 20 thou card. Take a
set of compasses (or mount a needle in your hand mini drill) and prick through
the paper into the plastic card at each corner of the side elevation. Carefully
remove the plan and join the dots on the card with a fine pencil before cutting
out with a sharp knife. When you come to prepare the second hull side, stick the
plan back on as before and pick up the holes already made in it with your needle
(or whatever) before repeating the process. The beauty of this method is that it
is easier to get two identical hull sides. However it should be realised that
this technique cannot be used where the subject vehicle has hull sides which
slope vertically (like the A9) or horizontally (like the -front of the Russian
BT tanks) since the side view is foreshortened. In this instance the shape of
the hull side needs to be constructed on the plastic sheet.
9. The next task is to cut a long strip of 20 thou
card from which will be made the hull bottom, top, glacis etc. The width of this
strip will thus be width of those pieces. This strip will be all that is needed
for the hull of a tank which has a simple basic design (like the T60), but many
vehicles will have upperworks which overlap the tracks and wider pieces will be
needed for this. These can be out from a wider strip. The length of each
individual piece can be taken from the drawing, but care must be taken to allow
for overlapping pieces where appropriate. If two plates are going to meet at
about 90 degrees then one can be made to overlap the other - this is easier than
chamfering both edges to a 45 degree angle. More acute or obtuse angles require
chamfering.
10. The need to chamfer the edges of two pieces of
card which join together stems from the fact that plastic card of any thickness
is three-dimensional. If the edges of two pieces meeting at an acute angle are
not chamfered then a V-channel is formed at the join. This is unsightly, wrong
and makes the structure very weak. It is really vital to chamfer the edges so
that the two plates butt neatly together. This is simply done using a file or
the edge of a knife. One other point to remember in preparing the basic hull of
the vehicle is to cut out any openings (for hatches, engine grilles, etc.)
before assembly and, where appropriate, to install grilles and the like. More on
engine grilles later on.
11. Twenty thou card is not a realistic thickness
for hull & turret tops since, in I/76 scale, it equates to about 40mm of
armour, however this is only apparent if it intended to leave open hull &
turret hatches. The problem can be partially circumvented by making a
‘sandwich’ of plastic card for the roof, or whatever, in which the hatches
are to be cut. The upper part of the sandwich is cut from 10 thou and the
required hatch opening is cut out to the correct size. Underneath this is
cemented another piece of card in which a larger opening has been cut. The
apparent thickness, viewed from above (outside the vehicle) is that of the 10
thou card, yet the structural rigidity of 20-30 thou card is retained.
12. You will probably find that the action of
cutting out the various parts required causes small burrs to appear along the
edges of the card - remove these with the edge of a knife blade or with fine
abrasive paper. It is now theoretically possible to start assembling the basic
structure, however if it is cemented together in its current form it will lack
rigidity and he prone to flexing. To strengthen the whole thing internal
supports or bulkheads are needed. The shape of these will generally be the shape
of the hull cross-section, but take care to allow for the thickness of the hull
sides, top & bottom. For the method of construction I have outlined above,
the bulkheads will be some 40 thou narrower than the strip from which the top,
bottom, glacis, etc. were cut. Transverse bulkheads are the norm, but fore-andaft
bulkheads are sometimes of value, usually when they are used to support a 'ridged-roof'
type of structure such as an engine deck. The exact number of bulkheads required
will depend on the dimensions and proportions of your model, but I usually aim
for one every half inch or so.
Basic Assembly
13. Assembly of the basic hull can now take place,
but before doing so take a few minutes to ensure that everything is ready for
assembly - it's very frustrating, not to say difficult, to have to take it apart
again! Prepare some short narrow strips of Sellotape or masking tape to hold
everything together while the cement is drying. Start assembly by cementing one
hull side to the base, next add the internal bulkheads, the second side and then
the glacis, rear, top, etc. Always use liquid cement for gluing the various
pieces together - superglue tends to dry too fast, thus preventing any small
adjustments that may be necessary. Superglue can however be used to reinforce
existing internal joins as it can be used fairly liberally without melting the
card.
14.
There are a number of important points to stress about the whole procedure of
basic construction. Do try to be accurate in the marking & cutting out of
the component parts - it should be possible to work to an accuracy of at least
0.5mm, probably less. Even small errors, particularly in length, will be very
apparent when you come to fit the suspension! In connection with this, try to
get into the habit of discarding anything which you know to be wrong or substandard.
When assembling the basic hull, take great care to ensure that everything is
square where it should be. Don't just trust
your eye to do this, use set-squares or a jig to ensure that your 90-degree
angles are just that. If it's any consolation, experience is no guarantee of
getting this right by eye alone (as I have recently found out to my cost).
15. Once the basic hull structure has been assembled
put it aside to set thoroughly - this will take 24 hours or so. It can then be
tidied up, which usually means removing the slight overlap of the top, bottom,
etc., from the hull sides and removing any burrs which have risen between two
joints. These processes can best be done by scraping with the side of a knife
blade, finishing off with fine abrasive paper.
PART 2 – DETAILING
1. The choice of detailing as the second article in this series might seem a strange one as I have yet to discuss some basics such as the construction of suspensions and the like. However I prefer to do my detailing as I go along. This is not to suggest that it is a chore - I personally find it the most rewarding part of producing a model. It is difficult to know exactly what detail can and can't be included on a 1/76 scale model - there is often a trade-off between making something that is slightly over-scale or not reproducing it at all. I usually try to reproduce something as finely as possible, then see if it looks right.
2. Most modellers will be familiar with the basic
materials used for detailing - plastic card of various thicknesses, plastic rod
and strip. The most useful way to acquire the latter is to buy the packs which
contain an assortment of various sizes and diameters. Plastic tubing is also
invaluable and can he stretched over a candle flame in the same way as sprue to
produce fine diameter gun barrels and exhausts - if you get this right (I don't!).
you can even produce the correct taper to gun barrels. 1 don't make great use
of stretched sprue, preferring to use very fine 10 thou plastic rod this
ensures a consistent diameter if a quantity is needed. [ supplement this with 5
amp fuse wire, used when sharp curves or radii are needed (plastic rod seems to
spring out of these shapes). One tool that I didn't mention in my last article
is a pair of fine needle-nosed tweezers - these are obviously very useful for
detailing.
3. It is obviously impractical to explain every
technique used in detailing - each model is different in this respect. However I
intend to outline some of the areas which are common to all or some vehicles.
Hopefully you will then be able to translate these techniques to the actual
vehicle that you are modelling. One general tip 1 would advise is to build a
balsa cradle to support the model while detailing and finishing the hull - this
minimises the handling of the model and the risk of damage to the work already
completed. If the cradle is built such that it does not project above the
trackguards it can be used until the suspension components come to be fitted.
Engine
Grilles
4. One bit of detailing that you will probably
encounter fairly early on is the production of engine grilles. These fall into
two general types, mesh & louvered grilles. Neither is too difficult if some
forethought is given to construction and
this is not started at too late a stage. A little effort on louvers &
grilles often pays a handsome reward whereas few things look worse than a
black-painted rectangle representing the same!
5. The appearance of etched brass now means that the
mesh type is probably the easier to make, although the required design will be
dictated by the vehicle being modelled. t use a fine etched brass mesh sheet
from the Airwaves range marketed through E D Models even better (if you can find
it) is a fine gauze sold, 1 believe, under the ‘Truckmaster’ banner.
Modelling in 1/76th doesn't seem to call for the extensive use of etched brass
that appears ‘de rigeur’, in larger scales and I personally fi nd it
difficult to use, but I make exception for these mesh sheets.
6. The exact design will depend on your prototype,
but the mesh can he arranged to sit below, level with or proud of the engine so
itself. Construction starts during basic fabrication of the hull (rear) when the
square aperture is cut out. Make the cut-out slightly smaller than the size of
the finished grille by about half a millimetre all round - the difference is
used as a small lip to support the etched brass sheet. The hull interior
revealed by this aperture is painted matt black. On the T60 the finished grille
is raised slightly above the engine deck and 20 thou strips can be used to do
this. The rectangle of etched brass
representing the grille is then cemented in place using a sparing amount of
superglue. Finish the grille with strips of 10 thou along each edge.
7. Louvered grilles are harder to make but
still worth the effort. The basic grille is made from a sandwich of wide and
narrow strips cut from plastic card. The wide strips will represent the louvers
while the narrow strips
will
space
then correctly. The exact thicknesses required will depend an your prototype,
but 10 thou is a good starting point. The louver spacing will only appear even
if all the faces are deburred before cementing and if the narrow strips are
sufficiently wide, about 60% of the width of the wide strips. Both vertical and
angled louvers can be made.
8. It is important to get the size of the louver
right. The depth obviously must be such that it will fit into the hull. The
length and width of the louver should be exactly the same dimensions as those of
the aperture into which it will eventually fit. Cement spacers of 15/20 thou
plastic card to the ends of the louver 'sandwich' so that the upper face of the
louver projects above the top face of the spacer by an amount equal to the
thickness of plastic card used for the hull deck plate. The finished louver is
then cemented snugly into the cutout so that the top face of the louvers is
flush with the outer face of the engine decking.
Trackguards
9. Almost all tracked AFV's after 1918 had some form
of trackguards and these are best made from 10 thou plastic card. The easiest
way of getting everything the same width is to cut one long strip of plastic
card for all the pieces required. In many cases these trackguards were
fabricated from thin sheet steel and had strengthening ribs pressed into them.
There are a couple of ways of
reproducing these ribs. The easiest is to score the plastic card with a
scribing tool or tip of a knife blade, deburring the piece an completion. A
harder, but slightly more effective way is to make the trackguards from a
sandwich of 5 thou plastic card, the lower half being the
full width of the finished trackguard with thinner strips cemented on top,
leaving gaps where the pressed ribs are required.
10. It isn't necessary to mark the position of the
trackguards on the hull sides before assembly of the basic hull as pencilled
lines will often be removed in the course of tidying up the construction.
However don't leave it until the suspension components have been added as it
will then be difficult to position a ruler on the hull side. The trackguards
need to be supported perpendicular to the hull sides while the cement dries.
Many vehicles had either overlapping superstructures or stowage boxes above the
trackguards the T60 has small stowage bins either side of the rear hull. The
vertical faces of these items, if prepared in advance, can be used to support
the trackguards during construction. However some vehicles, the
Russian BT series among them, had pretty bare trackguards - these can be
supported in construction by right-angled sections of balsa wood attached to the
hull sides using double-sided tape (good-quality tape is quite powerful, so
remove some of the 'stick', by pressing your fingers on it a few times). The
balsa blocks can be removed once the cement has dried thoroughl. Obviously this
can't be done if the roadwheels have already been cemented in place.
11.
Tack the trackguards lightly in position and check their position and alignment
before running liquid cement along the join with a brush. Triangular fillets
will often be needed to reproduce the web joining the front section of the
trackguards to the glacis plate. Many vehicles have rounded front and rear
trackguards. Gentle curves can be reproduced by pressing the plastic card round
a suitable former (such as a ball-point pen barrel) until the required shape is
achieved and held. More pronounced curves are best made by cutting out and
sanding the profile required from balsa and moulding the flat trackguard around
it in boiling water. Trackguards with rounded edges can be made by scraping the
outer edge with a knife blade until
Rivets
12.
The subject of rivets is often a contentious one amongst modellers. Probably
the best option if it is a task new to you is to try a number of the different
methods and see which suits you best. Obviously it is better to choose a subject
which has a relatively small number of rivets (only a few vehicles have none at
all) if you are doing it for the first time. The basic options are as follows:
a.
Ignore the rivets until the painting stage, then represent them with small dots
of rust-coloured paint applied with a fine brush. I find this method
unsatisfactory - it is difficult to apply straight rows, difficult to get a
consistent size and the finished items appear two-dimensional (which they are).
b.
Shave the rivets off a suitable AFV kit (the Airfix Lee/Grant is popular for
this) using a sharp knife, then pick them up one by one (with the moistened tip
of a knife blade) and apply to your model using plastic cement, the latter
smeared on in very small amounts with a fine brush. Again, I personally don't
like this method - many 1/76 kits have rivets like soup plates and it is
difficult to shave them off to a consistent size.
c.
Cut the rivets individually from 10 thou plastic rod using a sharp knife, then
pick them up and apply as for b. above. This method isn't particularly easy, but
it's not as bad as it sounds. Don't make a `log raft' of plastic rod and stick
it to double-sided tape before slicing the rivets off in groups - it's nigh on
impossible to lift them off again' 1 work on a glossy magazine and the slight 'give'
in the surface stops the rivets shooting off in all directions if they are out
slowly and with a sharp knife. Carefully moisten the tip of your knife blade
before using it to pick up the rivet. Once the cement has dried, the heads of
the rivets can be carefully sanded using fine abrasive paper to produce a
uniform row of rivets.
d.
The last option is the well-known one of embossing them on the reverse of the
plastic card using a needle or compasses. This method is certainly quicker than
b. or c. but I feel that there are a number of problems associated with it. It
isn't always easy to get a consistent size of rivet, the rivets must be embossed
before the required shape is out from the plastic sheet (or the part will
distort) and, finally, the technique cannot be practically used on plastic card
of 20 thou or thicker. This last point means that the basic construction must be
done without rivet detail, then `skinned' using 5 thou sheet on which the rivet
detail has been embossed.
13.
As you have probably guessed I use method c. above and it works for me.
Whichever technique you employ, don't try and do too many rivets at a time - I
aim to finish about thirty or so in a session, then do something else. I don't
actually mark the position of each rivet on the model with a pencil but rely on
positioning them by eye. This is easier if working along the edge of a panel or
surface (as is often the case). A pencil line helps if running a line of rivets
across the middle of a panel or face.
Other
details
14.
Most vehicles have some form of exhaust and these can be made from plastic rod
or sprue, with pipes from thinner rod. A nice touch is to make the end of the
exhaust pipe from 'stretched' plastic tubing so that it appears hollow. Plastic
tubing can, with care, be stretched over a tlarne in the same way as sprue. Many
vehicles, particularly those dating from the 30's and 40's, had grilles or
screens fitted over the exhaust silencer. These can be made from the same etched
brass gauze referred to above. Cut out a rectangle from the brass sheet, anneal
it over an exposed flame and bend it to shape. Usection screens can be formed
around a short length of rod or sprue. If your screen has a frame, bend the
brass to shape before adding the frame from 5 thou card.
15.
Gun barrels can be made from plastic rod or tubing of the appropriate thickness.
I have already mentioned that a taper can be produced on small-calibre gun
barrels (typically, 37mm guns in (1/76 scale) by stretching plastic tubing over
an exposed flame - a point I didn't make is that care is needed to ensure that
the stretched tube stays straight as it cools (few tanks have curved gun barrels...
). Larger-calibre gun barrels in 1/76 scale can be made from plastic tubing
without the need for stretching and a taper can be introduced on these by
careful sanding with a knife blade and with a collar of abrasive paper wrapped
around the tube.
16.
Small lifting eyes are best made from 5 amp fuse wire twisted around a pin. Cut
off the eye together with a small stub of the twisted section, then glue the
stub into a fine hole drilled in the surface of the model using a smear of
superglue. Larger eyes can be made from the small rings which form part of many
Historex figure kits, if you have a means of identifying and purchasing these (Historex
parts used to be available separately. but 1 don't know if this is still the
case). Hinges on visors, crew and engine access hatches are made fairly easily
from scrap card and fine 10 thou plastic rod. The pattern of these will vary
front vehicle to vehicle.
17.
Exposed headlights are something of a problem, especially if something more than
a silver-painted face is required. If the headlights are especially prominent,
like those of the British A9 or Matilda I; then it is worth making an effort to
reproduce them accurately. The method below is some considerable trouble but is
fairly effective. It uses the clear sprue found in model aircraft and (a few)
AFV kits. File the rear curved face of the reflector on the end of the sprue,
then sand and polish it to as smooth a finish as possible. Next, cut vertically
through the sprue to produce the headlight which can then be mounted on the
vehicle using either a short length of rod or stretched sprue or a frame made
from fuse wire (as appropriate for your prototype). The two finishing steps need
not be done straight away, but should be performed before the model is finally
painted. These are as follows:
a.
Paint the reverse face of the headlight silver.
b.
Mask the front face of the headlight using masking fluid or small circle of
masking tape.
18.
If the above sounds difficult, then I can only say that it is! Headlights made
in this way are very flimsy, especially if mounted on a fuse wire bracket. I
don't think it is a practical method for lights smaller than about 1.5mm
diameter and these can be made or adapted from those contained in AFV kits.
These items can be hollowed out and the reflectors painted a silver/grey colour
if desired.
19.
There are two ways of representing closed hatches and panels such as those found
on engine decks. One way is to scribe the outline of the hatch using dividers, a
scribing tool or the tip of a knife blade. This technique is quite reasonable
but it can be quite tricky scribing circular corners and irregular shapes. It
can also be difficult to hide the evidence if you make a mistake!! The other way
is to use 5 thou plastic card. Incidentally, if a hatch is flush-fitting with
the decking, try not to take the lazy way out by just representing the hatch
itself from 5 thou. It is more realistic to cut out the deck surrounding the
hatch from 5 thou as well, leaving a small gap to delineate the panel.
20.
These then are a few of the techniques that f use when detailing a scratch-built
model. I would be the first to admit that they are not the last word on the
subject and would encourage all to try their own ideas. You might even end up
writing an article!
One
area of detailing that 1 have not covered, deliberately, is that of finishing
suspensions - I intend to discuss this aspect of scratch-building in my next
article.
PART 3 – SUSPENSIONS
1. The suspensions of scratch-built armour models illustrate, in microcosm; the challenges and rewards of this aspect of the hobby. They can be undeniably fiddly and time-consuming to construct but the finished results can be very satisfying. Easiest are what might be termed ‘big wheel’, suspensions (such as those on vehicles using Christie type running gear, e.g. the British A13 And Russian BT series) and vehicles with torsion bar suspension. These vehicles had the suspension components hidden within the hull, with only the roadwheels on view. At the other end of the scale, the most complicated to model are those which comprise a largish number of small wheels supported by springs & suspension arms - the Vickers 6 ton derivatives, the Italian M13/40 series and vehicles like the Matilda
2. The techniques used to model suspensions are no
different to those needed for other elements of the vehicle being reproduced.
However a number of points are worthy of mention. Dimensional accuracy is
particularly important. If, for instance, your roadwheels are even slightly
over-large the effect will be, at best, very noticeable. At worst, it won't be
possible to fit them onto the hull. The Airfix Crusader is a good example - the
roadwheels are well moulded but about 3/4mm too big in diameter. The kit
designers got round this by making the hull a scale 15" too long, but if
your scratch-built Covenanter or A13 hull is the correct size, the wheels won't
fit properly.
3. One obvious feature of vehicle suspensions is
that they usually have a number of identical components. Try to make sure that
these are identical on your model also. If I require four suspension arms cut
from 20 thou card, I mark out all four at the same time with common centrelines
and use dividers to ensure that lengths and dimensions are the same. Never cut
one out and trace round it hoping to reproduce the shape exactly. In short,
employ the scratchbuilders' attributes of care, patience and accuracy even more
diligently when building suspensions!
Roadwheels
4. The logical starting point lot the suspension is
to construct the roadwheels. Whenever possible, use or modify roadwheels from a
commercial kit - this saves a lot of labour. The availability of suitable wheels
will depend on a number of factors. The prototype being modelled might have the
same components as a vehicle available in kit form. Some of the Russian BT tanks
had identical roadwheels to the later T 34 and the Airfix kit can be used for
these. Even if this is not the case, suitable wheels might well be available.
The roadwheels for the little T 60 can be taken without modification from the
Matchbox Pzkpfw 2 or Wespe kits, the sprockets and track come from the Fujimi
Pzkpfw I.
5. The inspiration to select a particular kit wheel
(the ‘light bulb in the brain’) is a quality that develops with experience
of scratchbuilding and with knowledge of the kits available on the market.
Some kits are particularly useful in this respect - the Fujimi Matilda Il and
the Esci Pzkpfw 35(t) are good sources of small
roadwheels, for example, while the Fujimi Pzkpfw 1 wheels & tracks can be
used to model any vehicle with Carden-Lloyd type suspension.
6. Don't despair if suitable wheels aren't obviously
available as it will probably be possible to convert or modify kit items.
Practically the only requirement for a source roadwheel is that it is the right
diameter - the thickness, hub and detailing can all be changed i1 necessary (more
on this below). Spoked roadwheels are more of a problem since they are only
found in a few 1/76 plastic kits. One source of small 6-spoked wheels, however,
is an etched brass sheet (ref. MF 12) available from Scalelink. This sheet
contains an assortment of spoked wheels between 2-6mm in diameter. Being etched
brass, they lack depth and surface detailing but this can be added as required.
7. One point to remember when making up roadwheels (indeed
suspensions as a whole) is that they are 3-dimensional - i.e., don’t forget to
check that all components are the correct thickness. This point is easy to
overlook since the running gear is usually hidden or the plan view by the tracks
and trackguards. Care in this respect will avoid misfortunes like the wheels and
tracks sticking out beyond the trackguards (excepting the Russian KV 1, where
they are suppose( to!). Once thicknesses of plastic card have been decided upon,
the thickness of the suspension units can be calculated by taking 2( thou as
0.5mm, 40 thou as 1 mm etc.
8. Remember that the roadwheels in some kits are not always of the highest quality and may need modifying even if the pattern is exactly correct. For instance, the detail of the Airfix T 34 roadwheels is excellent, but the thicknesses of individual wheel halves is rather variable. These items can be slimmed down to a correct and consistent depth by placing them face down in a `well' made from two laminations of plastic card, where the upper lamination is the required depth of the finished wheel. The rear face is then sanded down until it is level with the top face of the well.
9. As a last resort, it is possible to scratchbuild
roadwheels from discs of plastic card. I have yet to try it myself, but if you
do so take care to ensure that your scribed discs are the same diameter. A way
round this is to use either a leather punch or the punch and die set available
from Historex agents. Alternatively, one master wheel can be made and copies
cast in resin.
Sprockets
& Idlers
10. Sprockets and idlers can be constructed using
similar techniques to those described above. They are often of
a more complex pattern, but only two of
each are needed! It is usually worth removing the sprocket teeth around
those parts of the circumference where the track is to fit as it makes this
latter job somewhat easier. The spoked brass wheels referred to above are
particularly useful as quite a number of tanks had or have sprockets with 6
spokes, doubtless to save weight. Dished sprockets can be made with these brass
items by placing them over a well similar to that described in para. 8 above and
pushing down hard on the centre of the wheel - a dished depth of
about 1 mm can be added in this way.
11.
A plain round wheel of thin section can be modified to make
Suspension Units
12. The techniques above can be used to construct
the simpler type of suspension units. More complex suspensions group smaller
wheels in pairs or fours, supported by suspension arms and leaf springs. I
usually start by sketching out the likely construction to get an idea of what
will fit and overlap where. This also helps in evaluating the required
thicknesses of various items. When planning construction, try to have a regard
for the strength of the finished item. As an example, consider the make up of a
suspension unit for the Italian M13/40 medium tank.
13. The M13/40 suspension units each have two pairs
of roadwheels, each pair being joined by triangular brackets. The triangular
bracket, of each suspension unit are themselves connected to the central unit (mounting
the leaf springs, etc.) by curved suspension arms. For the sake of scale
accuracy and appearance, it is desirable that the front suspension arms and
triangular brackets (those nearest someone viewing the model) be cut separately
from plastic card and cemented together at an appropriate stage in construction.
However the rear arms and brackets are largely hidden by the roadwheels and leaf
springs, so there is no reason why they cannot be cut out as one (albeit
complicated) piece of plastic card. This will provide a simple basis for
subsequent assembly of the suspension unit and a strong means of anchoring it to
the hull when complete.
14. Leaf springs are best made from laminations of 5
thou plastic card on a base layer of 10 thou. Rather than make a series of
individual springs one by one, it is easier and more accurate to make one wide
lamination (of the correct cross-section) then to cut slices from it for the
individual springs. However, ensure that the laminations are cemented together
with plenty of cement (and allowed to dry thoroughly) as they otherwise have a
tendency to de-laminate under the pressure of the knife edge when being
individually sliced.
15.
One challenge in the production of these multiple-wheel suspensions is that of
ensuring that the wheel spacing are correct and uniform. This can be made easier
by constructing a small jig to hold the wheels while they are cemented to
brackets or suspension arms. The jig is made of a couple of laminations of 30
thou plastic card.
Mounting of Suspension Components
16. The exact manner in which suspension components
are mounted on the vehicle hull will depend on the type being constructed.
However the first stage should be common to all models and involves the
construction of another jig (!!) to position the hull correctly above the ground.
I use a combined balsa & plastic card jig. The balsa strips are used to
position the hull at the correct height, while the plastic card base and
microstrip runner act as flat surface and guide respectively for the wheels
while the cement is drying. The vehicle hull is temporarily attached to the
balsa using narrow strips of double-sided tape. The advantage of this set-up is
that the wheels can be positioned squarely and in the correct plane, avoiding
that ‘wheels in space’ look...
17. Large wheels can be simply cemented onto the
hull sides using ‘axles’ made from discs of plastic card - use this method
where possible since it is easier to get the lateral spacing correct and
consistent. However the use of such discs in conjunction with smaller wheels
presents something of a problem. The small disc size dictated by such a wheel
diameter (if the former is to remain invisible) means that the cemented area of
the join is itself small and relatively weak. However it can be strengthened
considerably by drilling the disc and wheel and inserting a short axle of
plastic rod. Drill the hull sides before Cementing the axle/disc in position. It
is necessary to mark the axle position carefully on the hull side before
drilling (to avoid the 'wheels in space' effect), but the hole can be made slightly
oversize, allowing a bit of ‘play’ in positioning the wheel.
18. There are a couple of small points to make about
torsion bar suspensions. Firstly, remember that the layout of torsion bars in
the hull means that the roadwheel positions left and right aren't normally
mirror images of each other and the convention of plans is such that only one
side is usually shown. This isn't a problem as the difference in positioning
will usually be apparent from photographs. Secondly, it often seems to be the
case that the axis of the roadwheels of a torsion bar suspension is in the exact
plane of the hull baseplate - this makes it difficult to drill locating holes.
Again, it can be easily circumvented by mounting the plastic disc/axle
combination eccentrically on the inner face of the roadwheel.
PART 4 - TURRETS & TRACKS
1.
The last in my short series of articles will sweep up the remaining areas of
construction, principally the construction of a turret. A couple of techniques
are most pertinent to this part of construction so will be described here.
2. The general techniques and skills of turret
construction are the same as those needed for building the hull, as covered
earlier in this series. However there are significant differences in the order
in which individual pieces are cut out and cemented, for most turrets at any
rate. It will be remembered from my first article that the normally accepted
method of constructing a hull is to build it such that the top, bottom, glacis,
etc, overlap the hull sides, the latter being cut out slightly smaller to allow
for the overlap. For turrets, it is slightly different. Turrets usually have a
flat top and bottom with curved or angled sides. For this reason, it is usually
easier to first cut out the top and bottom, then construct a cruciform
arrangement to hold them the correct distance apart before adding the sides,
front and rear.
3. Start by marking and cutting out the top and
bottom of the turret, including any hatches that are to be left open. Remember
to cut these out slightly underside to allow for the subsequent addition of the
sides, front and rear. The step of an overhang or turret bustle can be added
using a laminate. Next, cut out a strip of plastic card with a width equivalent
to the required height of the turret minus the thickness of the turret top and
bottom - this will be used to make the cruciform. From this strip cut out a
section following the side cross-section of the turret, allowing for the
thickness of card to be used for the front and rear. A similar piece is cut out
following the front cross-section, then cut vertically in two to fit either side
of the previous part.
4. Cement the three elements of the cruciform to the turret base then add the turret top. If your turret is to have open hatches, then it will be necessary to take account of these in positioning the elements of the cruciform. otherwise it easier to cement them in place about the centre of the turret. The 'interior' of the turret and cruciform can also be painted matt black at this stage if it is intended to leave turret hatches open. The whole of the above construction should be made from a reasonable thickness of plastic card, 20 thou for all but the smallest turrets. Allow this assembly to dry thoroughly before proceeding with further construction.
5.
Continue by marking and cutting out the sides, front and rear faces of the
turret. As always, allow for overlapping construction when marking out these
pieces and remove any opened hatches, vision devices and pistol ports before
cementing them in place. Most mantlets can be added after the basic construction
has been completed, the exception being some drum mantlets. These can be made
before adding the turret front by cutting out an aperture for the mantlet and
cementing a drum or cylinder to the inside, with the correct are projecting
through the chamfered cut-out in the turret front.
6. It is the nature of turrets that many are wholly
or partly formed of curved or conical surfaces. Many modellers are concerned
about producing these, but they present no special problems. One advantage is
that the greater strength of a curved structure means that a thinner plastic
card can be used for construction. A curved vertical turret face can be formed
by bending or moulding a strip of plastic card (10-15 thou) around a former of
the correct shape (my wife's nail varnish and lipstick containers often seem to
be suitable formers for 1/76 turrets!!).
7. Conical turret faces can be constructed quite
easily if it is remembered that a conical turret is essentially a truncated cone
and that it can be made in a similar way to the wizards' hats beloved of small
children. Take your scale plans and project the turret sides upward on the paper
until they intersect at a point in space above the turret. Use the arc lengths
thus created to scribe a curved strip of plastic card with a pair of dividers.
The conical faces of the turret can then be cut from this strip. If your
prototype turret is formed from both curved and flat plates (such as the Russian
T26 and BT series tanks) then construct it using separate pieces, following the
original, and support the joints from behind using small scraps of plastic card.
8. Detailing of the basic turret can then be started,
using techniques identical to those described in earlier articles. Small calibre
gun barrels (20mm and below) are best made from plastic rod - hollow out the end
with a drill if you can. Gun barrels of 75mm calibre and above can be made from
plastic tubing and a taper can be introduced to these by careful shaving and
sanding with knife and abrasive paper. I make early WW2 vehicles, many of which
had 37-45mm calibre guns. Suitable plastic tubing isn't commercially available
for these and I have been using supplies from a ball-point pen barrel that I
successfully stretched over a candle some years ago (this is about to run out
and I shall have to attempt another.). One other point of turret detailing
worthy of mention is the interior detail of hatches where these have been left
open.
Tracks
9. The last major items of construction to consider
are the tracks. These are a problem for scratchbuilds, as they are for most
other 1/76 scale models. If at all possible, try to avoid scratchbuilding tracks
- I have only needed to do so once, for a BT 5 model. The difficulty is that few
I/76 scale kits have tracks of reasonable quality - exceptions are Fujimi kits (particularly
the Pzkpfw I and Type 97 series) and a couple of Airfix models, the Type 97
being one. Like roadwheels, the selection of suitable tracks is a quality that
develops with experience of modelling and scratchbuilding. The Fujimi Pzkpfw I
tracks are particularly valuable for the many smaller AFVs that had a double row
of track teeth. Over-wide tracks can be cut down to the correct width. I use a
single-edged razor blade for this, pressing vertically down through the vinyl
rather than using the cutting motion of a knife (this tends to stretch the
material).
10. The only type of tracks that 1 would contemplate
scratchbuilding are the simple plate tracks of many WW1 and some 1930s vehicles.
I made the BT5 tracks referred to above by cutting out a long strip of 10 thou
of width equivalent to the pitch of each tracklink. I cemented a length of rod,
representing the trackpin, to one long side of this before slicing individual
links of the correct width. I assembled the tracks using a ‘link and length’
technique similar to that found in many larger scale kits. The relatively long
runs of track (along the top and bottom of the roadwheels) were assembled by
cementing individual links to a thin (1 mm) strip of 5 thou plastic card.
Shorter lengths were used for the tracks sections between the roadwheels and
sprockets/idlers. Individual links were cemented around the circumference of the
sprockets and idlers.
Finish
11. Construction of the model is now just about
complete and it is ready for finishing and the addition of the tracks. The
techniques for finishing are beyond the scope of this series and the only
comment that I would make is that the unpainted model is likely to be fairly
greasy after many hours of handling during construction. I degrease mine by
immersing them in bleach for a few hours before spraying the base colour. The
bleach doesn't seem to affect the plastic or construction and can be rinsed off
under a trickling tap.
12. It is my hope that some of you will have been
encouraged to try their hand at scratch-building. Certainly it demands care and
patience, but it really is the most rewarding form of modelling and it is
enormously satisfying to see a finished scratch-build and know that you built
it, completely.
- Andy Lang
