Scratch Building a Bridge

2003-8-5

Some time ago I decided that I wanted to build a diorama that featured water and - being unemployed - that meant scratch building the whole thing myself. Searching the internet provided a picture of a bridge in France that would be the basis of my model. This would suit a planned theme of a British rearguard on the retreat to Dunkirk, about to blow a bridge when the Wehrmacht appear on the scene. View Pic 01


In order to construct the bridge I first cast two sheets of plaster the correct size for the finished bridge, using card formers to make the shapes for the arches. These were cast in an old kit box strengthened with tape. I thought that any card that adhered to the plaster would provide texture but upon reflection it made it harder to tool the stonework. View Pic 02


To engrave the stonework in the plaster I used a set of industrial engraving cutters and a motor tool with a fine bit. The lines of stones around the arches and the parapet were cut fairly neatly and regularly, whereas the remainder are a random pattern. View Pic 04 and Pic 05


When completely engraved the two sides were assembled using formers cut from card to fill the ends and form the roof of the arches. A plastic carrier bag was placed between the formers and the bridge to prevent it from sticking. View Pic 06


A mixture of rubble from unsuccessful casts and fresh plaster was poured into the inside of the bridge to cement the parts together and make the tunnel roofs. View Pic 07 and Pic 08


After the plaster was dry the parts are removed from the formers and set aside to fully cure. The card former for the road was then glued in place. The diorama is to be built on a sheet of MDF (an off-cut - free from a DIY-store). With sides added to the base to support the walls and groundwork, and card formers to contain the water at the front and rear, the bridge was cemented in place while the rest of the parts for the dio were constructed. View Pic 09 and Pic 10




You can see more of Dave's excellent work in his section of the User Gallery!