How to make your own stone bridge. What do you think of mine? - Model Railway Engineer

How to make your own stone bridge. What do you think of mine?

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stone bridgeWant a stone bridge on your railway? You could go and buy a plastic kit… Or you follow these 7 steps and make you own.

Since posting the above photo on the Model Railway Engineer Instagram page I’ve had a lot of requests for more information on how I made it. Here’s what I do. What do you think?

1. Work From Reference Material

For starters I find a real-life version of the type of bridge I want to make. For perfectionists, this should be from the era and location your layout is based on so the material and architecture is correct.

In my case, this means lots of visits to Cornwall taking photos of the thankfully plentiful buildings still around but searching google.com/images is an equally good source.

Alternatively, if you’re not too fussed about matching an era or location, just search Google.com/images for terms like ‘stone walls’ and you’ll have a ready made library of reference material.

With source references sorted it’s time to make the model.

2. Make The Master

For the surface material I use Clay but it’s not the easiest material to work in – we’ll get to this in a minute – so I first create a template in Plasticard (styrene sheet) although thick cardboard could also be used.

I make up the model in this, cutting the sheets to the size and shape required and then temporarily fixing them together with track pins.

In the case of the bridge, the two sides were cut first and then the middle section (that lies under the rails) was cut and then fixed between the sides.

With the Plasticard model ready I trial position it, checking that it fits in place and looks right. It often takes several iterations of my this stage until I’m happy with the size and shape.

Note: For long railway bridges where the track might bow under the weight of the rolling stock supporting beams may be needed. In other models I’ve used spare rails (removed of their sleeper webbing) and fixed under the middle section of the bridge to do this. In this model, which is short, and road bridges that won’t be supporting weight this wasn’t required.

3. Clad It In Clay

Once I’m happy with the Plasticard master it’s time to render it in clay.

Take a block of soft clay (I use Daz — available in most craft shops) and flatten it to the desired thickness (around 2mill) and size required to cover your entire Plasticard surface.

Then use the Plasticard model as a template and cut identical shapes. Using track pins to assemble the Plasticard model mentioned previously means it can be disassembled and the separate pieces used as templates from which to cut the clay.

Now reassemble the model, this time gluing it, coat the card in PVA and wrap it in the clay cut outs.

Shortcut: If you struggle with scribing and painting and want a quicker path to completing your bridge you can skip the next three gems and glue photographs to the model (which I covered here) to give the a very credible look. There’s absolutely nothing wrong with this approach I just prefer the texture the clay produces.

4. Scribe The Stone Work

While the clay is still damp, I then scribe the detailing of the stone work into the surface.

For the N scale of this bridge this is fiddly to put it mildly.

Each stone brick is just milli-meters long so an implement with a very fine point it required. (Is it me or are are a lot the stones on plastic kits the wrong scale?).

When I first started working in clay I tried dragging shape points — needles etc — through the clay but this often resulted in tears. Now I very dentistry picks with the point filled to a round point and faintly indent the clay with it creating a shallow line of joined dots which for all intensive purposes looks like the recesses where the stones that make the wheel would meet.

Timing: There’s a very fine balance between leaving the time it takes for the PVA to set so the clay is held in place to the point where the clay itself has dried out. The clay needs to be damp but not dry for the next step. I find about half an hour works but it depends on the room temperature and how fast the PVA sets vs drying time of the clay.

5. Apply Undercoat

Now let the clay dry and the PVA properly set — approximately 24 hours depending on the thickness and area to dry — and then apply a dark grey wash that will run into the recessed low points to create a shadow look in the finished model.

6. Dry Brush Top Coat

Once the wash is dry, dry brush on a top coat.

The exact colour wanted will depend on the colour of the original you are mirroring.

In my case, Cornish walls from the time I’m recreating were often Quartz (see here for a guide to what material was used where) and I use Vallejo acrylic water-based colours — Medium and light grey. This is then topped with a slight coating of white and black chalk dust to simulate the impurities in the Quartz.

7. Finishing Off

Although the wall is technically complete as a wall there is still a finishing touch that makes it just that little bit more realistic.

In truth, I got this idea off Martin Welberg and his amazing Mara Harbour (see below).

While looking at his beautiful work I noticed he paints the bottom of harbour building planks dark green to simulate moss and on examining bridges in rivers they too had moss growing around the stone work at the water edge.

A quick scour of my paints found a moss green and a bottle of Ak Interactive’s Slimy Grime light and dark (Ak00027 & Ak00026) and a quick test showed they resulted in the colour I wanted. Dabbing these on around the base areas and where the bridge pillars would meet the water gave the very subtle hint of plant growth that I wanted.

With the stonework complete it was then just a case of positioning and adding finishing vegetation at the points where the stones meet the ground.

I use a combination of photos of real plants growing on buildings and my imagination here: positioning them first, and once happy then removing, applying the glue and repositioning them. Materials are a matter of personal preference. I use a green kitchen scrubber type sponge and natural sponge torn up into tiny sizes and daubed with different shades of Vallejo Green and Woodland Scenics Foliage Bushes and Fine Leaf Foliage in Olive and medium Green. 

I’m reasonably happy with the result, what do you think?

I’d love to see pictures of your models if you make a bridge too! Also, I’m always looking to share tips that will help you so if there’s a particular item on your layout you’re struggling with making drop me a line and I’ll be happy to suggest ideas and tips that might help.



PS, If you liked these tips, you might enjoy my newsletter, Footplate. Over 20,000 model railway fans get my tips direct to their inbox with this. It's completely free, you can unsubscribe at any time and I promise to never spam you. Sign up now.

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