top of page
Building with photoengraving
We have fun building railway material starting from photographs.
Photoengraving allows us to obtain copper or brass models. It is a simple and complex process at the same time.
the necessary material is: a PC with a drawing program, some ferric perchlorine, some caustic soda, two plastic basins, two glass plates, and the documentation of the model we want to reproduce. For personal protection: rubber gloves and an acid resistant apron.
With the help of the PC, we draw all the parts of the model and transfer it on a transparent sheet. For faster corrosion, it must occur on both sides of the metal. Therefore the drawing must be printed twice
The brass plate must be degreased and cleaned perfectly, so that no traces remain, on pain of losing the job due to unwanted traces.
I clean it with alcohol and a clean cloth.
The photo-sensitive varnish is spread on the freshly cleaned plate and placed in the oven at a temperature of 70°. This operation must be done in the darkest possible.
In the meantime, the prints are assembled so as to match the two designs, and fix them with adhesive tape, leaving one side open to insert the painted copper plate.
The painted plate is inserted into the printed envelope and placed in the sun for 2/3 minutes on each side.
Immediately after, wash with the caustic soda previously prepared in a 5% water solution. 50 g per liter of H2O.
The washing operation must be accompanied and ends when the design emerges perfectly.
It is rinsed in running water and placed in the tank with the perchloroferric acid. With new acid, a 0.2 mm slab requires 2 - 3 hours of processing. For a toilet that has been used 3 or 4 times the time jumps to 5 - 6 hours.
When the development is completed, the work looks like in the photo above. Perfectly the same as the design we developed on the PC.
All that remains is to free the pieces from the whole, bend them as per the project and weld them building the desired model.
All the models I built, about ten vehicles for the maintenance of the overhead line, the shelter of the Follonica station, the bridge light signals and more, have undergone this treatment
bottom of page