“Designed in the 18th century by the artist Giovanni Battista Piranesi (1720-1778), Caffè degli Inglesi in Rome, just moments away from the Spanish Steps, is a prime example of a lost ‘cultural cafè’. Renowned for its eccentric Egyptian style, it was a main hub for British artists visiting the Eternal City. Although it was a key centre for culture and artistry, the café’s design divided opinion. Caffè Degli Inglesi only survived for circa 20 years.
When creating a three-dimensional model, it was obvious we needed to depict the two undocumented walls in a way that does not mimic nor assume, but can capture the spirit needed for the café’s re-interpretation. We are therefore suggesting the use of mirrored walls, providing an immersive experience, without compromising the integrity of Piranesi’s unknown original design.
For this project it was decided to make the wall thickness 3mm for ease of construction as well as keeping the material use to a minimum. Simple tray moulds were made up using strips of 3mm MDF that were double sided taped down to a base. This aids an easier removal from the mould once the cast has cured.
Note – if it is clear that a lot of the same component are require (in this case resin slabs) that it may be worth making the mould using a silicone to allow repeat casts and easy cast removal. As this project was very much ‘try it and see’ the required moulds were made as needed.
Once the basic mould was complete the surfaces were coated with a barrier coat of Vaseline to prevent the resin penetrating the surface of the MDF when poured.
The use of metal powders in casting allows us to create a lightweight and, when compared to full metal casting, low cost but effective substitute material. The process uses very fine metal powder to coat the surface of a desired cast that can then be polished as if it were cast in the metal in use. In this case Aluminium powder was chosen to emulate lead.
In order to guarantee a good coat of metal powder on the surface of casts the mould should be dusted with the desired powder. The excess powder can be poured from the mould and reused.
For ease and speed of casting fast-cast- polyurethane resin was used as the stock material for the cast slabs. The resin is usually mixed at a 50/50 ratio but always check the instructions as some brands do vary their instructions on ratio mixing. As we were going for a metallic finish overall metal powder was also mixed into the resin to back up the surface coat already ducted into the mould. As the resin is poured the metal powder particles naturally want to sink to the lowest point so having them in the resin only increases or chances of a successful finish on the face of the cast.
Surface Finishing and Laser Engraving
Once the slabs have poured they can be carefully removed from the mould and all being well will have a dull but flat finish on the down face. Using wire wool the surface can be polished up to the desired shine.
Next up for this project was the engraving of the Piranesi drawings onto the plates. Using the laser cutters Daniel and Vanessa were able to engrave into the polished surface of the plates as well as the back face which would end up being inside the model.
The roof components required heat forming to create its vaulted shape. This shaping occurred after being engraved and cut to shape which required significant time to figure out correctly.
The final detail to be added to the model was lead finishing strip as used on leaded windows. As well as finishing the panel gaps this strip. lent itself to the model design and matched the metallic finish perfectly.