The Cardboard Coach in Three Acts.
by Colin Binnie
Overture
The method of coach building I am about to describe owes little to my efforts but has been about for at least sixty years. The ideas are not new, the materials are old fashioned but the results are curiously satisfying.
The level of skill required is not high though a degree of patience is required. The materials are cheap and generally available. In fact an ideal beginners project. With this in mind I propose to be even more pedantic than usual. If the more experienced modeller finds this tedious I can but reply that he should not be reading this but should have written it instead!
A coach is essentially an elegant wheeled box for carrying people, if it is not very elegant and made of metal it is called a car. All the best coaches were more or less elaborately panelled with a projecting beading covering the joints. It is this panelling/ beading that provides the major challenge to the modeller.
A reasonable facsimile of a panelled coach can be made by laminating the sides from layers of card and treating the card with a hardening agent. That is all there is to it, but a few notes might help
Act 1
Scene 1 Materials and tools
Card
Not surprisingly, the major material of the cardboard coach.
The best quality card is undoubtedly Bristol board, available at the art shop at horrendous expense. But I am at heart a tight fisted skinflint so I like to use the ordinary manila folders beloved of office staff everywhere, I have also had success with the hard dark green card from which some filing cabinet pockets are made. Donald Boreham, may his shade rest in peace, swore by the card covers of the Birth, Marriage and Death Certificates which were the stock in trade of a Registrar. His coaches were made on his office desk in the breaks between marrying Elizabeth Taylor.
Hardening agent
Here I stick my neck out when I declare there is nothing so good, so perfect for our purpose as shellac. I do not mean those miserable bottles of shellac varnish nor bottles of french polish, button polish or knotting, with their added waxes and plasticiser but good old fashioned flake shellac. It is getting rare but I can still buy it at my local hardware shop at around 5GBP for a lifetime’s supply. It is prepared by dissolving in methylated spirit in a small coffee or similar jar and it is worth making it in three consistencies. Gooey, creamy like paint and runny like milk. I have used Ronseal and other proprietary wood hardeners and also well thinned cellulose and coffin varnish, but I shall use shellac in future.
To achieve that deep down protection and hardening the hardener must penetrate deeply. The surface hardens off and the deep down solvent slowly, oh so slowly, rises to the surface. If it is a solvent which can attack the subsequent paint job it may damage it months later. I have a Festiniog curly roof bogie van, fully lined and lettered which is developing a cracked surface that would do justice to an old master. I have used Ronseal and coffin varnish for general outdoor use with success but I am not prepared to risk a complex paint job again when I have shellac and know it works. Sure sign that I'm old. No spirit of adventure.
Glues.
Ordinary white PVA. For some jobs it may be diluted slightly with water. Epoxy i.e. Araldite, both rapid and the slow drying variety.
Wood
Any of the finer grained hardwoods will do. Obeche, ramin, lime, mahogany and holly all work well. I only use balsa for two jobs i.e. Internal panelling and roof support.
Tools
A couple of scalpels and spare blades. I like to use the short straight scalpel for general work and the curved blade to cut into a corner.
A fine whetstone for keeping the blade sharp. I have a couple of those Rolls Razor sets picked up for coppers at the car boot sale. They contain a very fine whetstone and a leather strop built into the lids. We are not resharpening an old blade abandoned by SWMBO after cutting floor tiles but merely keeping the blade in top condition. Sharp blades mean clean cuts.
Pencil about 2H, wooden not collet or propelling. Some means other than the scalpel for sharpening same and a bit of abrasive paper for keeping the lead pointed.
An engineers square. Through the years I have collected a number of these from a tiny 1/2'' long blade upwards. For this job something in the three to six inch range will be fine. A useful extra is a 12''square. Mine came from the local 'Pound Store' and though low quality is perfectly adequate.
A steel rule. A useful modification is to stick a piece of electricians insulating tape along the underside. This makes it less likely to slip when using it as a straight edge when cutting.
There are a couple of special tools which we will discuss when the necessity arises.
Scene 2 - The Prototype
We have dealt with all the boring stuff so let us have a quick look at a typical coach to refresh the image in our imaginations. Referring to my crude sketches (See Fig. 1)
there is a main frame with apertures for the doors. There is a longitudinal rail below the windows and if height permits, another above them. To this frame is screwed the panels and to keep the weather out of the joints a system of beading is applied over them. The constructional requirements of a coach naturally have an effect on its external appearance. The end of the coach has a substantial frame in its own right and this naturally takes up more space than the flimsy compartment dividers. Thus the beading/panelling at the end of a coach tends to be wider than that at the doors or compartment divisions.
The window glass in the main frame is usually fixed. It is inserted into the main frame from the inside up against the rear of the panelling or beading and secured into place with an inner window frame screwed to the main coach framing.
Within the door it is usual to have a sliding window usually referred to as a droplight. This is contained within its own sliding frame, which drops behind the door panelling. The glass of the droplight is thus set slightly deeper into the coach than the other windows. Hopefully, despite my efforts you now have a rough idea of the construction of the prototype. Fig 2 attempts to portray the construction of typical windows.
Scene 3 - The Model
We will attempt to model this in all its complex glory by laminating the side from thin card The coach side will be laminated from at least six layers of card and looking at my sketches they look far more complex than they actually are.
Fig 3 is an exploded view of the door area of a typical coach.
Layer 1 is the beading overlay with the external panelling scheme cut into it.
Layer 2 has an aperture which will form the front of the droplight frame, this is therefore slightly smaller than the window aperture in layer 1. In the quarterlight positions ( windows either side the door) the card is cut back, slightly larger than the window aperture, to form a glazing pocket extending to the top of the side. This enables glazing to be inserted after the side is completed and painted.
Layer 3 continues the quarter light pockets rearward and introduces the pocket for the droplight glazing.
Layer 4 contains the quarter light inner frames and extends the pocket for the droplight glazing.
Layer 5 has the droplight inner frame and the slightly larger recess of the quarter light position.
Layer 6 brings the droplight aperture back to full size and repeats the quarter light aperture of layer 5
Fig 4. is a similar scheme for a coach where droplights and quarter lights
are at the same level. You may puzzle this one out for yourself.
By now you should be totally confused but all the best plays do that. The overture just fills in time while the audience settles and finds the potato crisps. Act One introduces the characters and creates bewilderment. Act Two starts to unfold the plot and undo the damage done by Act One. Act Three limps along explaining what has become obvious. Any further Acts clear up the mess and the finale tries to show how clever we all are.
Act 2
Scene 1. The Stack
Without further ado let us get on with construction and to do this we make a stack of the card sheets that will be our coach side plus one extra sheet. The sheets should be large enough to make both sides of the coach with at least a couple of inches to spare. The sheets are glued together along one side and each layer except the bottom one is folded back so that they open like the pages of a book. Each fold needs to be a little farther forward than that of the layer above. Make sure they are well creased and fold easily. Pencil the layer numbers in the corners of the sheets, top layer is layer 1. Fig 5 will show what I mean.
Mark out both sides of the coach on layer 1. The sides should be drawn as a pair; bottom edge to bottom edge or top to top. I personally prefer to work top to top since the delicate bits in the upper side are kept in the middle of the sheet.
Thus the coach side is seen upright in the lower position and its mirror image is inverted above it. Marking out is simplified enormously since all the vertical markings are drawn across both coach sides. It also ensures that the sides will be a matching pair.
Most prototype coaches from a given company tend to have doors and quarterlights to a standard pattern, so making door and window replacement easy.
We can take advantage of this by making a template (posh name for bit if card with marks on !) of the horizontal dimensions of the door and quarterlight area with reference to the door centreline. We merely mark the door centrelines on the coach side and transfer the dimensions from the template. If a number of coaches is planned it is worthwhile using the other side of the template for the vertical positions and widths of the beadings. Now write the name and type of coach on the template and when you have finished marking out put it away carefully for future use. I must have dozens of templates stored in envelopes. I only wish I could find them!
Now shade the bits we are going to cut away to leave the top layer of the beading. Check and check again. This is the point of likely error and beyond this point there is no erasure. Hopefully Fig 6 will clarify my poor words.
Scene 2. Cutting Out.
A final check and we can start cutting out the beading. DO NOT cut the perimeter of the sides from the surrounding sheet. We need the surrounding sheet to support the work. Cut with light strokes. Attempts to cut through the layer in one go will drag at the card and result in buckled beading, maybe broken blades and even blood on the work. The gentle approach is also easier on the fingers and the temper. Keep the knife sharp.
We must cut, repeat cut, the unwanted parts out. Do not tug at the blank.
If the blank sticks go round again with the knife. Use the round edged scalpel blade with a forward rolling action to get into sharp corners.
I will discuss rounded ended panelling later. For the moment I propose to
get on with the general process of cutting out the coach side.
Fold Layer 1 up and out of the way. Layer 2 will be found to bear the scars from cutting out layer 1. Treasure the scars for these are your guides for cutting layer 2.
Fold layer 1 down again and mark out the droplights on layer 2. Shade any apertures that are to carry through unchanged. Mark out the window pockets for the quarter lights, slightly larger than the window aperture in layer 1.Cut the apertures in layer 2
Fold layer 2 out of the way and again using the cut marks as a guide mark out and cut layer 3.
With layer 4 we have a slight change in that the quarterlight window inner frames get smaller again and need to be the same size as the apertures in layer 1.
Obvious, fold down layers 3, 2 and 1 and lightly cut mark the outline using layer 1 as a guide! Fold layers 1,2,3 out of the way and cut holes in layer 4.
Layer 5 deals with the inner droplight frame in similar manner to the quarterlights in layer 4. However the quarterlights apertures themselves increase inside the coach so the apertures in layer 5 are about 1mm larger all round than those in layer 4.
Layer 6, the last one! Repeats the quarterlight aperture from layer 5 and increases the size of the droplight aperture to that in layer 1.
Admire but do not fiddle. Your card has nice sharp edges, the more you mess
about the more woolly they become.
Scene 3. Sticking together
Slip a bit of polythene sheet between layer 6 and the spare layer. Using PVA white glue thinned with water (see Act 1) stick layer 5 to layer 6, continuing up the stack to layer 1.
Do not stick layer 1 in place yet. Slip a piece of polythene between layers 1 and 2 and place the entire stack under a couple of heavy books for at least 24 hours. Remove the polythene and trim the solid lump that is layers 2 to 6 to final length, removing the end trimmings. Do not cut top and bottom. Fold down layer 1 and glue in place. Back under the heavy books for another 24 hours.
Finally, cut layer 1 slightly overlength. About 3mm projection beyond the rest of the layers at each end will do fine. Not very fussy as we will be trimming these tabs back on assembly.
Cut the top and bottom edges of the sides, at last freeing a pair of sides from the stack.
Draw a deep breath and relax.
Scene 4. Shellacking.
Now retire to the shed, garden or wherever the Domestic Dragon is unable to detect the smell of meths. Do not judge her sense of smell by your own, mine can detect beer at a hundred paces, whisky at half a mile and B.O. ten minutes after I exit the shower.
Slop a coat of shellac on to the coach side. We need the runny, milky consistency here. Turn it over and do the other side. Turn it back.. By now the first coat will have sunk in. Slop on another coat. Turn over. Continue to and fro until the side refuses to take any more.
Leave to dry out thoroughly. All the little whiskers should now feel crisp to the touch. Rub over lightly with fine steel wool and clean up window apertures with SWMBO's abrasive claw sharpeners. Dab with damp (not soaking) kitchen towel to remove dust.
Scene 5. Painting.
Now is the time to paint the coach side. A coat of grey primer will show any blemishes, which can be dealt with before proceeding. Paint with your chosen colour and put away to really harden off
Scene 6. Glazing
Cut windows to fit the pockets and try them in place. Cheap CD cases provide the window material.
Act 3
In which I propose to deal with the construction of the ends and other external bodywork externals.
Scene 1. Round cornered panelling.
I have used several different tools for this job, none is perfect. They are :-
The multi-hole leather punch. This is the plier like device with the rotating battery of hollow punches beloved of arts and craft shops. Not bad, cuts cleanly but suffers from lack of reach for our purposes.
The wad punch. These are the hollow punches sold for punching holes in gaskets etc. They are too heavy, too clumsy and need heavy resharpening to a thinner edge before use.
The home made punch. So easy to make. (See Fig 7.) can be of mild steel but is better in siver steel and hardened. Since the cutting edge chamfer is on the inside it compresses the waste not the work. It does the job well with a little practice. My personal favourite.
When doing round cornered panelling cut the corners first. The straight cuts can then be located by hooking the point of the scalpel in the curved cut at each end. Locating the punch with reference to the straight cuts so that the curve flows smoothly is beyond my small skills.