Stonewall finished!
The methods and experiments with the bridge, is paying off! The wall has almost none of
the errors encountered when working on the bridge!
The totally engraved/grated(?) wall was first painted grey with an acryllic paint;

It was then "weathered" with diluted "Betun de Judea"; (it´s very thin; you smear it on,
wait 1-2 minuttes, and then wipe it clean with a cloth) (a wash (heavily diluted paint)
with black acryllic paint could also be used)

The finished wall in its place at the alpine station;

I have now developped a specific method for producing these walls, with a result that
satisfies me.
I dont pretend to be an expert on this, after these few works, but the method is good for
somebody who needs flexibility and cost of materials close to 0,-!
Here is how I do it;
1) Build a rough model in wood/carton. (usually some left-over pieces will do)
2) Cover every visible part with a VERY THIN film of white glue (wood glue)
This is important so that the plaster will adhere well to the wood, also when grating.
Dont get plaster and glue mixed up, which will make it IMPOSSIBLE to grate the plaster! (bridge problem #1)
3) Cover every visible part with plaster. Around 1mm thickness will do, but not less.
Thick layers of plaster wil do also, but there is always the risque of cracks and
holes. Better to have a more accurate model of wood inside. (bridge problem #2)
4) When totally dry, grate the stones. First horizontal lines, which can be made using a
ruler. Vertical lines must be made stone by stone. This is very tedius, and seems to take
forever. Grating can hurt hands and fingers.
Dont worry about some cornes breaking off, cracks showing up, etc. during the grating.
This is exactly what makes for such a realistic result!
5) Paint everything with a diluted paint.
6) Weather everything with a HEAVILY diluted black paint. (Or the "magical" Betun de
Judea); Apply generously, wait, wipe off with cloth. (bridge problem #3)
Finished!