Tag Archives: Artifact Conservation

A Quick Retelling of the Cuban Archaeologists’ Visit

From second left to right: Roger Arrazcaeta Delgado; Marcos Antonio Acosta Mauri; and Yoser Martínez Hernández of the Gabinete de Arqueología of Havana, Cuba at their rowing stations in the chalupa, “San Agustín”.

By Dr. Sam Turner

Between August 25th and September 14th the St. Augustine Lighthouse & Maritime Museum hosted an archaeological cultural exchange which consisted of a visit by three Cuban archaeologists, Roger Arrazcaeta Delgado, Yoser Martínez Hernández, and Marcos Antonio Acosta Mauri, from the Gabinete de Arqueología, or Archaeology Cabinet, based in Havana, Cuba. This cultural exchange was possible through collaborations with the St. Augustine Archaeological Association which sponsored their travel and the Friendship Association which provided financial and logistical support. The purpose of the archaeologists’ visit was to participate in both underwater archaeological fieldwork with the St. Augustine Lighthouse Archaeological Maritime Program (LAMP) and in terrestrial archaeological projects with the City of St. Augustine archaeologist as well as to exchange ideas and methodology from within the international field. Additionally, the guest archaeologists assisted with the analysis of the ceramic material found on the Anniversary Wreck, which is the current focus of LAMP’s field work.

This particular cultural exchange program works to establish and deepen contacts between archaeologists and historians in both St. Augustine and Havana, Cuba in hopes of restoring cultural and scholarly ties between these two cities following a thawing in international relations. This is considered especially important given that these two cities’ histories have been closely intertwined for much of the last 450 years.

The Cuban archaeologists were able to explore the Anniversary Wreck with Museum archaeologists as well as use a new airlift – an underwater excavation tool – which LAMP has been experimenting with this field season. During their visit, they also visited many historically-significant sites in order to get a comprehensive overview of the history of our city. After visiting Fort Matanzas and the Castillo de San Marcos they became particularly interested in the bronze Spanish artillery captured during the Mexican-American War (1846-1848) and the Spanish-American War (1898). Other visits included: the Alligator Farm; the Spanish Military Hospital; St. Photios Greek Orthodox National Shrine; Tolomato Cemetery; and the Father Felix Varela Shrine.

Director of the Gabinete de Arqueología, Roger Arrazcaeta Delgado, was the featured speaker for the St. Augustine Archaeological Association’s monthly speaker series delivered at Flagler College on September 5th. His talk, entitled, The Frigate Navigator and its British Shipment: History and Archaeology, focused on a shipwreck east of the city of Havana which they have recently investigated and identified. The talk was well attended by approximately 75 people.

Our Cuban colleagues were especially pleased to meet and spend time with St. Augustine resident Dr. Kathy Deagan, one of the world’s foremost experts on Spanish colonial archaeology who took them on a guided tour of the first colony exhibit in Government house and discussed her work on numerous Spanish colonial archaeological sites in St. Augustine and abroad. They also had the pleasure and honor of helping crew St. Augustine’s tall ship, the San Agustín, an authentic and faithful replica of a Spanish watercraft known as a chalupa. This watercraft was built as a legacy project of the 450th anniversary of the founding of St. Augustine as a partnership between the St. Augustine Lighthouse & Maritime Museum, The St. Augustine Maritime Heritage Foundation, and the Fountain of Youth Archaeological Park. This replica vessel is used every year to reenact the landing of Pedro Menéndez de Avilés on Founders Day. Our Cuban colleagues were able to take part in the full landing rehearsal and were to have participated in the landing day festivities set to take place on the September 9th but those plans changed when an unwelcome visitor named Irma came to town.

While here, our colleagues pitched in with the rest of the Lighthouse staff to prepare the entire Lighthouse site for the hurricane which was a two-day process that included striking all the tent tops in our Heritage Boatworks area and boarding up windows. They weathered the storm at Lighthouse Field House where field students and visiting scholars are housed during their stay in St. Augustine. Following the storm, they helped reopen the site for business. Towards the end of their visit, we conducted a study and examination of the ceramic assemblage that was excavated from the Anniversary Wreck and currently under archaeological investigation by LAMP. This included a visit to the city archaeology lab where they met with outgoing city archaeologist, Carl Halbirt, as well as his recently-arrived-replacement, Andrea White. Carl shared a great deal of information including some of his most interesting finds here in St. Augustine, especially the recent excavations of the Spanish cemetery associated with the church of Nuestra Señora de Los Remedios on Charlotte Street.

Unfortunately, as another result of the storm, no archaeological work with the City Archaeologist was possible during this visit. Hopefully next time! We were honored to have international colleagues come to share with us. Our thanks to them and to all who helped host!

18th Century Cannon Conservation – The Next Step

On Wednesday, October 7, 2015, we will begin the final phase of conservation for the two large cannons from the Storm wreck.
Removing concretion
Removing concretion

Lighthouse archaeologists excavated the guns in June, 2011, and brought them to the lighthouse. In the first phase of conservation, as much of the exterior concretion as possible was removed using hammers, chisels and air-scribes. This was to ensure no other artifacts were stuck inside the concretion, and if there were any, that they would be treated and conserved separately. It was also necessary to remove the extraneous material to speed up the second phase.

When the cannons were cleaned off, they were placed in metal tanks to undergo electrolytic reduction (ER). In ER, the gun is submerged in a solution of reverse osmosis water and sodium carbonate. Sheets of expanded steel mesh were placed on the sides of the cannon and connected to a positive electrical anode. The cannon itself is connected to the negative anode.

The "long gun" cannon in its electrolysis tank
The “long gun” cannon in its electrolysis tank during a regular break for cleaning

By drawing the electrical charge into the gun, we can very gradually and safely extract the salt (built up over 230 years in a marine environment) out of the cast iron and into the solution. The solution is periodically replaced and refilled so that, over the months and years, the chloride content of the cannons is reduced to as low as possible. This is the main concern for conserving marine artifacts. If the salt is not removed, the material will continue to corrode and break apart from the inside out.

After nearly four years of ER treatment, the cannons are now ready to come out and move to the third phase.

The 4-pound long gun will be the first to be removed. We will drain the solution, lift the cannon out of its current tank with our engine hoist and gantry and be wheeled over to our secured conservation facility for safety precautions. The cannon will then be lifted and placed into a new metal tank and submerged in reverse osmosis water. The water and gun will be heated for an extended period of time to rinse the artifact. This will open the pores of the cast iron and help remove any final unwanted soluble salts and any extra sodium carbonate solution. The rinsing should take one to two weeks with occasional water bath changes. We will take samples of the water to ensure as much salt is removed as possible before the final sealing phase.

Andrew Thomson is the Assistant Conservator for the St. Augustine Lighthouse & Museum. He received his graduate degree and training from the Conservation Research Laboratory at Texas A&M.

The Secret Behind a Storm Wreck X-Ray

When concretions are brought up from the Storm Wreck excavation site, they are documented meticulously. This is to in order to record the location and any possible relation to surrounding artifacts and the site as a whole.

However, unless there are some very telling diagnostics or features, it’s usually very tough to tell what the concretion actually is. For this, we take the concretions to get X-rayed.

A two-legged mystery

Artifact 234 came out of the 2012 LAMP field season.

DSC09707

It was taken to Flagler Hospital to be X-rayed. In the ensuing images, it was possible to see three different types of artifacts. There were small lead birdshot (shown as the bright white dots), an iron spike (the bottom half of the image) and an intriguing two-legged artifact (the top half of the image). Continue reading

Copper cauldrons

You never know exactly what you will come across when conserving artifacts.

When an artifact is found on site, it is documented, photographed and X-rayed to determine what it is and if it’s something of interest to conserve. Sometimes, though, objects will be too thick or have too much material in the way to give a clear X-ray image.

Fortunately, in some instances, the artifact is identifiable and easier to work on.

In December 2010, LAMP archaeologists revisited the Storm Wreck site and saw numerous newly exposed artifacts. One such item was what looked like a large pot or cauldron. When examined underwater it appeared to be made of copper. Divers documented the find, marked the location and left it behind for possible excavation during the next field season.

17DEC10_033
Artifact on site

When the summer field school started again in June 2011, the archaeologists came across the pot again, but did not recognize the artifact. In between the initial discovery and the summer field season, the bottom of the pot had fallen apart.

With the bottom missing, though, it was possible to see a second pot inside of the first. Continue reading

Conserving the Past: Saving the “Storm Wreck” Cannons

As part of an exhibit project sponsored in part by the Department of State, Division of Historical Resources and the State of Florida, two of the largest and most recognizable artifacts at the St. Augustine Lighthouse & Museum are currently undergoing a little extra conservation.

Visitors to the lighthouse have seen two cannons outside of the Keeper’s House for the last few years. The 4-pound long gun and the 9-pound carronade were excavated in the summer of 2011 from the “Storm Wreck” by the Lighthouse Archaeological Maritime Program (LAMP). Shortly thereafter, they were delivered to the lighthouse with a number of other artifacts.

Setting up the gantry to move the 4-pound gun.

The guns were then mechanically cleaned with hammers, chisels and pneumatic airscribes to remove the outer layers of sediment and marine growth, called concretion. Removing this material significantly speeds up the next step of the conservation process. When the artifacts are as clean as can be without being damaged, they are put into electrolysis.

The electrolysis process consists of putting the artifact in an electrolyte solution and running an electrical current into the object. This helps remove salt from the metal and helps inhibit future corrosion. The amount of chlorides in the solution are monitored by titration testing. This allows us to see when the solution needs to be changed and when the artifact is done.

That step is where the long gun and the carronade have been for the past three years. Continue reading