Located on the north side of the Bramante Courtyard, where the courtyard received its name, is a colossal work of the Roman era that was, until the 17th century, in the center of the Atrium of the Constantinian Basilica of St. Peter's.

During the construction of the new St. Peter’s Basilica, the Pinecone moved to its current location under the pontificate of Paul V in the early seventeenth century. The Pinecone is 4 meters tall and the maximum diameter is 2.40 m., and it is cast with 5 elements soldered together (one bull, 3 base elements, a truncated cone element, and a cusp - which is missing ) with additions from successive periods that include a base.

As early as 2018, the restoration started with analytical research and several inspections from the restoration report in the Bulletin of the Vatican Museums from 1986. The Bulletin was fundamental because it accurately describes the techniques for the execution of the work and it provided an accurate internal inspection.

The photographic documentation of the intervention allowed restorers to reference and evaluate the trends and types of degradation (typology and progression) and the current state of conservation. To preserve a character of continuity and promote a homogeneous reading, its maintenance should follow the same drawings from the eighties. In particular, restorers adopted the same numbering system of the single scales (or more scientifically "bracts") in respect to the natural spatial spiral phyllotaxis of the cones (or "strobili").

From the very first inspections, the bronze surface appeared aged and there was a noticeable presence of the widespread use of old protection agents that had been applied during previous restorations. The south side of the Pinecone, facing towards the Courtyard and not covered nor protected by the "niche", was subject to abrasive action from atmospheric agents.

The evidence is in the widespread presence of percolation lines. A thick layer of protection (synthetic resins, mixed with waxes, and corrosion products) still appeared consistent along the sides exposed to the North, which the architecture protected from behind. Restorers integrated many gaps in the bronze with resins during previous maintenance interventions to chromatically adjust the color to
the original.

Thanks to the analysis conducted by the Diagnostic Laboratory of the Vatican Museums on protective samples taken from the surface, they identified the Pinecone’s natural chemistry (two-component acrylic-based synthesis products with strong aging) and designed an
appropriate intervention.

By means of chemical and mechanical cleaning, restorers were able to accurately analyze the outer metal surface. Restorers stripped the surface through repeated washings with demineralized water and they used acrylic resins (applied by brush) and microcrystalline waxes.

A mechanical seal altered the old additions from the previous restoration and chromatically camouflaged the colors to match the original through the use of natural pigments embedded in epoxy resin. Restorers applied the mechanical seal with paint brushes.

 

Bramante Courtyard Pinecone - Figurative Capital Monument

During the restoration of the Pinecone, restorers also worked on the Figurative Captial Monument that is below and supports the Pinecone. On the Capital, the "... figures...represent the coronation and acclamation of a winning basket . The naked athlete is in the middle; the palm is in his hands. The presidents of the games have crowns on their heads adorned with medallions and carved images of the losers and heroes to honor those celebrated in the games. The auctioneers and bystanders seem to proclaim the winner and celebrate it, while some other personalities, in charge of the care of the games, seem to prepare the wine to refocus themselves against the vanquished rivals. The right side is missing the main figure, perhaps lifting up the crown.

The winner is about to dispose of the terrible armor of the fighters, the raw baskets. He has shaken their hands and insinuated their wrists by half an arm..." 1807 E.Q.Visconti, The Pio-Clementino Museum, Rome - table XLIII, pages 75-76

Then in 1908, "...the great Bronze Pine was removed for work...in order to proceed with the restoration of the ancient capital which supported it and threatened to fall. The difficult work was carried out with the necessary assistance of the porters. In the interior then two blocks of travertine were placed in order to be able to entrust you with the external marble decoration by means of metal spranks...".(observ1908 Restoration G.Galli ASMV, Weekly housing reports, 12-08-1908)

Patrons funded the restoration of the Pinecone in 1986. Restorers from the Marble Restoration Laboratory provided shower washing and capital cleaning, consolidation, and a final washing with deionized water. They additionally attached the marble figure on the capital of the Pigna (fell after a storm and was not replaced for a long time) and provided an acrylic resin treatment on the entire surface of the capital.

Restoration Intervention

Restorers used hammers, chisels, pneumatic micro chisels, precision micro drills to mechanically remove old fillings and reconstructions from previous restorations that are unsuitable for the compostion.

 

Cleaning Intervention

To extract the copper corrosion, restorers tested EDDS (ethylenediamine-N,Ni-disuccinic acid), EDTA trisodium trihydrate, Sodium Hexamethophosphate, and Rochelle Salt (Sodium Tartrate) in concentrations between 0.25M to 1M. They also used supporting agents such as Sepiolite, and Agar-Agar. Here you can see the microanalytical investigations as they test the specific samples on the column.

 

Methodologies Adopted

For the abacus, base, and plinth, restorers used deionized water in cellulose pulp and Sepiolite tablets. It was not possible to use lasers to remove carbonate layers and concretions, because, in the tests performed, it caused "blackening" (presence of metal oxides inside the constituent material).

To restore the capital, restorers lowered the carbonate layers, concretions, and black crusts with the help of precision micro-drills. Afterward, they used a saturated solution of ammonium carbonate in cellulose pulp and sepiolite tablets. To finish, they used micro sandblasting.

Unlike the abacus, base, and plinth, the use of lasers to remove carbonate layers and concretions gave excellent results. However, it was decided to proceed with a faster and more controllable methodology, such as microsanding.

To restore the deep grouting of the capital, restorers used pozzolan, putty lime, and hydraulic lime in a filler to binder ratio of 3:1.
To restore the surface grouting of the capital, restorers used various marble dust, slaked lime, and hydraulic lime in a filler to binder ratio of 2:1.