Construction of the L’Obsidienne 
road roller (1)
Page created on 22/02/2025.
Description of the kit, qualities and defects
Manufacturer’s description of the real model
This model is a VR 12 H tricycle equipped with a Baudouin twin-cylinder diesel engine with pneumatic start. It weighs 10 tonnes and its weight can be increased to 14 tonnes by adding wheel saddles.
Some vocabulary points
I am not a specialist in roadworks and their vocabulary, and even less so in English.
In my ignorance of the actual terms, I have named certain parts according to their apparent function, such as the wheel scrapers or the rear bumper, which, according to some photos, is not a bumper but is used to attach optional accessories to the rear, such as claws used to break up old tarmac before redoing the road. Connoisseurs will forgive me for these possible inaccuracies.
Contents
Here are the contents of the L’Obsidienne kit box.
The instructions supplied are very brief. So you’ll need as many photos as possible. I’ve put some together here.
Appearance of the parts
Note: most of the faults I’ve noted can be found on all the resin kits I’ve had in my hands. The most annoying is the lack of symmetry and the deformation of some parts. Perhaps this is due to the fatigue of the supposedly silicone moulds? I was expecting this from the Richier road roller, which I saw working when I was a child. Still, this is pretty frustrating.
- Resin parts
The body is finely moulded, especially the engine bonnet grilles. Unfortunately, there are quite a few micro-bubbles, particularly on the “nose”. There are also some asymmetries: the “nose” is not the same height on the left and right - oh, it’s only a tenth of a millimetre off, but it shows. The walls of the cab are asymmetrical, one being clearly deformed.
The wheels have large bubbles on the tread. What’s more, the width of the tread is not constant. So you can’t rely on perpendicularity to drill the axles.
A compressed air cylinder (tank) for starting was missing from the delivery. It was sent to me by my dealer (Star Boutique), but it doesn’t correspond to the drawing in the instructions: there is no fixing pin, and it’s too small. So it will have to be remade.
Explanation of how the starter motor works. Source.
Regarding compressed air starting, just before stopping the engine, you need to stop supplying fuel to one of the engine’s two (or three) cylinders.
A lever is used to switch it to compressor mode. The air tank is filled to a pressure of 30 bar (60).
To start the engine, the cylinder that served as the compressor now receives air from the air tank and turns the engine.
As the engine has a flywheel, as soon as a certain speed is reached, the decompressor in the 1st cylinder (and possibly the 2nd) is closed, the engine coughs, smokes and finally runs on diesel. At this point, close the compressed air supply and switch the last cylinder to the engine position, and the launch is complete.
In principle, the charge in the air tank is enough for two or even three attempts; if it’s failed again, you take out the cranks…
Personally, I can’t figure out how the air supply to a single cylinder can turn the engine over more than half a revolution…
- White metal parts
These are the most objectionable parts. The front wheel arch support is too thick, asymmetrical and has a large burr (but this is a common fault).
The roof of the shelter is deformed and a little flattened: the folding angles will have to be adjusted. What’s more, the internal engraving for positioning the uprights is out of line. This is a design error.
Some parts are supposed to represent details of the rear of the machine, but it has to be said that they bear little resemblance to reality.
- Photoetched parts
The photoetched nickel silver plate contains various accessories: control levers and steering wheel, and various small parts.
Brass rods of various diameters are also supplied.
Kit référence 14003
Rouleau compresseur Richier ep III-IV (kit)
32 € chez Star Boutique