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7/8ths Kartoffelloren

by Doc Turner

An account of the building of a trio of German potato wagons from kits from Bertram Heyn.

"You were only supposed to blow the ...doors off"

The joy and the tribulations of modelling in 7/8ths scale

While the lazy man inside me does love to buy ready made items "off the peg", I know only two well that when I do so, the outcome is a five minute wonder. The biggest advantages of modelling in 1/13th scale are twofold; you can source cheap as chips accessories at 1/12th scale but to build a decent collection of rolling stock, you are obliged to make it yourself, either completely from scratch, or by using a very small supply of kits. Perhaps my greatest delight is to take a kit and use it to build on. That's how I made the Sand Hutton parcel brake; I used a Raif Copley base and overlaid a new box on it.

Not being exactly spoiled for choice in the way of kits means you get to cast around for whatever is out there. That's how I stumbled upon Bertram Heyn at Modellwerk.


 A thoroughly nice bloke, he sure makes a smart bunch of kits quite apart from the fantastic architectural work he does. He speaks and writes impeccable English and provides a good aftersales service too as I can testify. I found, as my build progressed, that I seemed short of materials. Either I had misunderstood the instructions (and my German is not great) or Bertram had made an error. An email was followed by a swift simple apology and more wood arrived within a couple of days.

I wanted  rake of three; I always think that looks best. To make them look 'of a piece', I elected to build them together so I confused myself by 'borrowing' bits from different boxes. My next error was to think it wise to use my cut saw to create identical planking thus forming my own template. Not a good idea. For some reason, identical they were not.

In the end, I found the very best way to create, for example, the wagon sides, was to glue the supplied, oversized planking together, side to side, using the rather watery but really excellent PVA that comes in each kit. That way, I had a flat slab onto which I could pencil the positions for the cross beams, leaving overhang at both ends. I used a set square to mark the positions after the glue had gone off (and this PVA is very fast) so that the right angles would be exact. This model won't work unless great care is taken over those right angles.

The cross beams were glued to the lines, square butted to one end but overhanging at the other. That way, once fast, I could use a razor saw to cut them off, using the plank edge as a guide. This looks so much better than when I cut each cross beam to length first and then tried to glue it in place. I use spring clips to squeeze pieces together for setting and pretty soon I had quite a production line going, right across the dining table. With six sides and six ends to build, I found that by the time I needed some clips for the next piece, the glue had set on the first. I know I'm making it sound quite laborious but there is a lot of repetitive work in building three kits. I suspect that if I had built just one, I might not have had the oomf to get back to the other two!

While the kits look rather fetching in bare wood and brass, I knew I wanted mine to look as if they were used for carting murphys. The wood grain is overscaled of course but I could not bring myself to paint and simulate wood grain on such a number of complicated vehicles. If I had made just one, I think I might have done so. On a single vehicle, I would have sprayed with Zinsser BIN, rubbed down to smooth flat to eradicate grain completely then mixed up a load of acrylic to the precise colour in my head. Once that had been applied, I'd realise that it didn't actually work to the eye and mess with it. A final spray coat of satin polyurethane would bring the appropriate surface sheen. A total labour of love for a single vehicle but totally inappropriate for a rake of three.

I played about with spare wood and some weathering sprays I have found useful in the past. They are water soluble and the spray pattern is a very fine mist. The colour that worked best was Moss Green with a touch here and there of Oily Brown to avoid too much uniformity. I need not have worried. In the end it all looked grey! The wood soaked the stain up hungrily and for minimal wetting which was good as it reduced risk of warping and  dried fast enough that I could then use sanding sealer before working the surface over with medium sandpaper. I rather like the way that technique allows the edges to be blunted and the original wood colour to come through.

I had the forethought to blacken all the brass work once I had separated it all from casting sprues. I must say, it all needed very little fettling. 
Very good, simple, positive brass coupling castings

Bertram supplies 10 BA hex bolts for fixing the axle boxes onto the sole bars using thoughtfully predrilled holes. I did appreciate that and it meant that once assembled the wheel sets ran sweetly. And that brings me to one vital point. This kit is for 45mm gauge track and the excellent wheel sets supplied need to be changed for my 32mm track. No problem if you have a lathe or, as I do, a handy Paul Miles who will nip down the shoulders to give exactly the right back to back. The wheels are already blacked and are top quality insulated steel. They run extremely well in the provided axle box castings.

Supplied wheel set with reduced shoulder to allow 28mm back to back

Very good cast axleboxes and the holes for the 10BA bolts already drilled. Luxury!

Bertram supplies hundreds of brass nails which also benefited from Carrs Blacking. I really liked these nails even after inserting hundreds of them. The reason I'm not gnashing my teeth is that these nails are really hard so they don't bend as you thrust them home. They have evenly domed heads and their shanks are ridged. What this means is that you can push them into a 1mm drilled hole with modest force and they stay put, doing away with the need for glueing. One small bugbear was the need to shorten them so that points did not project on the other side, but this was only a little tedious.

Most excellent nails but they need trimming.

That the instructions are in German is no big deal, thanks to Google translate, but I fear not every dilemma I met was covered by what was written. However, not needing to glue the pins meant that I was able to readjust if I didn't like the look of something.

It occurred to me that the best way to ensure that the sides met the body accurately was to make the sides very precisely to ensure they were precise rectangles, then to use the finished sides as formers to set the ends to the floor. That makes more sense than attempting to set the ends precisely at a right angle first then hope the sides offered up truly. Similarly, I discovered that it made sense to assemble the fixings and only drill and pin when I was satisfied with their position.

My first assembly attempt. It looked right with a set square but when I tried to fit a 
door. it simply looked wrong. Far better results were achieved when I used a pair of
 doors to set both ends to. This end prised away reasonably easily as the PVA was only
12 hours set. Any longer and the end would have been trashed. Note also that I had 
pinned the floor. Out they come for blacking!

Another issue I was pleased to foresee was the line of floor rivets that would be very close to the end wall once set. You can see that well in the photo above. It would be too close to permit a Dremel to drill the holes! Having built the pitched floor onto the base frame, I marked and drilled the holes and was able to insert the nails after the full assembly and surface finishing. I realised that if I tried to use PVA to assemble parts that had been treated with sanding sealer, adhesion would be poor. It was a better idea to drill the holes, assemble the bare wood, stain, seal, sand and finally insert the pins. It worked well. Even as close as those end rows of pins, I was able to drive them home without a problem

Ends glued using a finished side to work to, ensuring an accurate fit.

The doors are simply hung onto a hook at the top and there is a fixing system with a lifting plate at the bottom. The castings are truly excellent. Slots have to be cut to permit straps to slide through and be pinned to the planking. This is a little tricky to achieve neatly but I came up with a wheeze to halve the problem. I glued the top bar onto the top plank first, allowed it to set, and, using a set square, pencilled in the outside edges to ensure a true right angle to the top bar. The idea was then to fix the side uprights, butting them up tightly. to the top bar, following those pencil lines. The overhang at the bottom would be cut off after the uprights were set. Neat and sweet. Assuming the five planks were properly butted to each other and were uniform, I would end up with a truly rectangular door. I realised that I could cut a rebate at the top edge of the outer uprights, exactly the right width and depth to accept a strap. No more, no less. Even more neat. I went to suck a lemon to take the grin off my face.

Look how neat that slot is! Neat-ish. That ring is riding a bit too 
high on the hook 
but, if the door needed to sit lower, I'd probably ease the strap up on the left, to 
truly level and pin the other two holes.

The bottom strap, however, sits smack in the middle of the bottom plank. Nothing for it then but to drill out a slot. All too late I worked out a way of setting the drill in the Dremel chuck at just enough depth to clear the 10mm wide plank. Before that, I chewed a lot of wood. Admittedly, some of that would be hidden by the strap but I sure lost that grin. Here is a slot I cut before I wised up.

A very nasty slot but, to be fair, when the strap is fitted, you
can't see it.

Now, door closed, hook engaged. Time to level that strap and pin it.

Spud-u-like wagon?