Engraving Bricks

The wall with 25.001 behind it.

Choice of material

Some of the more succesful buildings for my first fiNe-scale layout Spaubeke were made from card engraved with bricks and coloured with aquarel pencils and gouaches. The photo below shows one of those buildings, the goods shed on Spaubeke:

Using this method can be satisfying, but the scribing of bricks is hard work. The above building was entirely hand made in 1993. This requires carefully selected paper, it has to be soft enough to be indented but it must lead to crisp results. The scribing is pretty much tyring due to the force needed for scribing in combination with the required concentration to avoid errors in scribing.
Since that time several tools have popped up to make life easier. For accurate hand scribing of parallel lines a Geoff Jones angular cutting board will make life a lot easier.

But of course nowadays there are all sorts of machines that can do this scribing much faster and without errors. I also found a 'new' material that is better suited than card. This material was already waiting some years in a corner as I collected it as potential useful material on a show in 2016 or thereabouts. But it took a lockdown period to come around to it and see where it was good for. The material in question is from Maquett and it concerns PVC-foamboard (PS605-01). The sheet I had was 2 mm thick but they have a range in thickness from 1 mm up, it comes with a blue-greenish protective sheet on one side. Compared to my old paper card solution this board is much easier to scribe because it is softer and it allows finer detail than can be made by hand.
The main difference with those other foamboards such as advocated by Emmanuel Nouallier, is that it doesn't have any paper cladding that needs to be removed. More important is that the Maquett foam is much finer, allowing much finer detail to be modelled. Studying his techniques will lead you to conclude that his bricks are not at all to scale and the courses are very deep, necessary because the foam is actually too coarse not allowing fine enough detail and hand imprinting is limiting accuracy somewhat. That foam is thus completely unsuitable for fiNe work in our scale, the combination of stiffness and bubble size are not good.

I first tried some hand scribing and concluded that it was excellent stuff. Thus the next step was testing further ideas for different subjects such as road surfaces and various brick patterns but now CAD based:

test pattern with irregular corners.

2 sorts of street pavement in natural stone, note the curve simulating the pattern in heavy used roads where stones get displaced by passing traffic.

Herringbone pattern for dutch streets, initial colour steps in grey concrete, pinkish red iron oxide pigmented concrete bricks can be used as well, yellow pigmented concrete bricks are rare but certainly do exist.

Of course you may compare this method to 3D printing such a wall or surface, but this engraving approach not only wins in crispness, but also in size of the models that can be made and the speed of producing it. Flat 2D work is much faster than building up a layer of resin. Also this foam material is much easier to process in colouring than 3D UV resin and there is no need for chemicals in cleaning and no UV hardening. All drawings were done in 2D using Coreldraw.

Pattern generating

Wall pattern pulled apart.

The wall pattern is a straight stack of 4 repeated patterns with the offsets based on brick height. A single pattern (purple) for the headers. There are 2 patterns (red,green) for the stretchers that are shifted by half a brick length. The bottom is filled in with a straight line (blue) to close the pattern. These are actually multipoint sawtooth lines with a single start/end point and can be made as long as needed for the area to fill. The height is copy/paste to fill the area required. The pattern doesn't need to be straight as demonstrated above with the flowing curve in the lines of the street pavement.

As further demonstration example a mixed area of concrete and bricks infill is shown for paving harbour or industrial areas.

stelcon with brick infill.

output of pattern.

quick attempt in colouring

The actual size of this pattern is 50 x 25 mm, thus in this enlargement you can clearly see that the first generated square in the center has bricks that are somewhat deformed *). This is due to the depth being slightly too deep in relation to the tip cone and size of detail, the remaining squares were done with reduced depth to about 2/3 of its initial setting of 0.2 mm. The colouring is an initial mix with a black brown wash to accentuate the courses, followed by medium grey/white/ochre mix for a concrete colour. The rusty steel edges were done with a lining pen, all using Vallejo acrylic paint. This paint is not recommended, it is horrible to work with and dries much too slow. With hindsight applying David Eveleigh's stipple technique for the panels will probably work much better, this requires a stiff brush and better paint, for instance that of the Amsterdam acrylics range of Talens. Further work can be by adding more greens and other pigments and a touch-up of the top surface with concrete colour, lifting some bricks and planting weeds can make it nicely into a neglected complex.

*) for really large view: left click, choose open image in new tab, this will show the image in highest resolution.

Construction of the wall

The material that I had obtained was 2 mm thick, this is OK for a façade, but too thick for a brick wall, except for the posts. Thus I decided to mill some pockets of 0.3 mm deep such that the posts stand out. In order to arrive at a 2 mm thick wall the back was thinned by 1 mm. Two parts were later glued back to back. Any gluing can be done with ordinary white glue and under some weights to keep it flat. This approach avoided double sided engraving, entirely feasible, but one shouldn't make life difficult when it is not necessary. Working the other way around by sticking engraved strips into a milled pocket would have done the job too. The material can be easily cut using a sharp hobby knife or scalpel, for instance cutting windows in a façade can be done by hand.

Engraving was done using my CNC mill, but other options are feasible, for instance you can use a filament 3D printer when you attach a plain pin to it. The pin used is made from a broken hard metal drill with 3 mm shaft now ground into a rounded and polished pin of about 30 degrees angle using a diamond blade and 2 minidrills. The round polished detail is important as a too sharp pin may tear through the foam surface leaving burrs and shreds and round because you need to be able to go in all directions.

The resulting brick walls were later cut into strips and glued together.

Colouring

The colouring of the wall is done by water based acrylic paints. I used the Amsterdam range from Talens. Started out is by first colouring the courses in a light grey/white colour and wiping off the excess on the brick surface. Than the brick surface is coloured using a brick colour mixture made up of red/orange/blue with a flat brush in dry brushing technique. This is followed by dusting over with pigment powders made from Conté à Paris pastel crayons to enhance the brick courses and this time wiping off the brick surface using a lightly wet brush. Further detail can be added using aquarel pencils and more pigments in dedicated places. The final lot can be protected by coating with a matt laquer or fixative

close-up of the final brick wall

The whole process comprised into a video:

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copyright: Henk Oversloot
date: 27 Februar 2022