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.

New pistol concretion

Remaining pistol concretion before additional x-rays

In the previous blog, X-rays of smaller artifacts from the 2015 Storm wreck field season were discussed. The smaller objects are taken to Monahan Chiropractic Medical Clinic to determine what is inside.

The larger items, however, are brought to Flagler Hospital Imaging Center where they are able to accommodate the bigger and odder-shaped concretions. Nine such artifacts from several different field seasons and locations were recently taken to the Imaging Center to be X-rayed.

While there are some intriguing finds, one in particular stood out.

Artifact 13S 353
Artifact 13S 353

Concretion 13S 353.1 was excavated in the 2013 field season and had obvious unusual characteristics from the start. It appeared to be a conglomeration of at least three or four possible different artifacts, two of which were somewhat identifiable.

The large ring on the top of the concreted sediment turned out to be a cupreous ring. It is probably the remains of a copper or brass cauldron rim and the rest of the vessel corroded away. Soon after the concretion was excavated, but before it was X-rayed, the ring separated from the other objects and was put in storage separately. Continue reading

Lighthouse History 1994 – 2014


This ninth and final installment in our series on the history of the St. Augustine Lighthouse focuses on the recent history of the lighthouse and the creation of the
St. Augustine Lighthouse & Museum.

Click the links below to read previous posts in the series:

1994 – 2014

The lighthouse has been opened to the public since 1994, thanks to the tireless efforts of the Junior Service League of St. Augustine. From the beginning, it has been a popular destination for the local community and the many visitors our city attracts each year. So popular in fact, the Junior Service League (JSL) quickly recognized that daily operations required funding and upgrades.DSC_0282

In 1996, the JSL began a fundraiser to pave the walkway from Keepers’ House to the lighthouse and to rebuild the brick wall that historically ran the perimeter of the light station. For a donation, visitors could purchase a brick in the walkway or the wall and engrave it with a personal message. This campaign provided the necessary funds for the site upgrades. It was so successful that the program is still running and new brick areas are now available behind the Keepers’ House and in the courtyard.

In 1998, the JSL created The St. Augustine Lighthouse & Museum, Inc. (SAL&M), a 501(c)3 non-profit organization, to handle operations of the light station as a historic site and museum. SAL&M began interpreting the site through exhibits in the Keepers’ House and with staff members and volunteers sharing the stories of the lighthouse and its keepers. In those early years of the organization, all operations, including staff offices and the gift shop were in the Keepers’ House along with the exhibits. Continue reading

New Name, Logo Establish Lighthouse & Museum’s Focus on Maritime History

The newly re-branded St. Augustine Lighthouse & Maritime Museum aims to enhance its maritime research and education programs to benefit residents, visitors, members and donors.

ST. AUGUSTINE, FLA. – For nearly three decades, the nonprofit St. Augustine Lighthouse has been known internationally as a leader in historic preservation. But under the new moniker of St. Augustine Lighthouse & Maritime Museum, the Smithsonian Affiliate organization aims to enhance its reputation in the field of maritime history and research as well.

“Maritime history plays a foundational role in the story of the lighthouse, as well as the greater story of St. Augustine,” said Executive Director Kathy A. Fleming. “Our mission has always been to tell the stories behind the Nation’s Oldest Port and that hasn’t changed. But with the new name and logo we can better convey to the public that we are much more than just a lighthouse.”

2015 SALHMM Logo

The new brand is one of many enhancements coming to the museum in the next year.

In the spring of 2016, the museum will be launching a new exhibition entitled “Wrecked” to tell the story of a Revolutionary War-era shipwreck off St. Augustine’s coast. Utilizing artifacts conserved at the Museum, the exhibit will not only shed light on the tragedy behind the New Year’s Eve 1782 shipwreck, but also how Lighthouse archaeologists were able to find, document and recover pieces of this wreck. Continue reading

Community Collaboration: A Power for Good Makes a Great Contribution to our 450th

Dr. Sam Turner on board the chalupa replica.

This article first appeared in the St. Augustine Record on Sunday, Sept. 6th.

In 2007, the St. Augustine Lighthouse & Maritime Museum received a special category grant from the state of Florida for the First Coast Maritime Archaeology Project. In addition to funding nautical archaeology in the Nation’s Oldest Port, the grant paid for a visit to the Archive of the Indies in Seville, Spain, to obtain documents important to St. Augustine’s past.

The research trip, carried out during the summer of 2008 was conducted by the Lighthouse & Maritime Museum’s Maritime Archaeological Program, known locally as LAMP.  Museum archaeologists discovered a number of documents that shed considerable light on our port City’s early Spanish maritime history.

Dr. Sam Turner on board the chalupa replica.
Dr. Sam Turner on board the chalupa. Photo by Kirk Chamberlain.

Of great importance was the discovery of a document that listed a Spanish chalupa. When most people see the word chalupa, they think of something tasty from a Mexican restaurant. This chalupa was something quite different.

In this case, the reference was to a type of Spanish vessel that was built in St. Augustine in 1597 for the use of the St. Augustine presidio, or military establishment. The inventory listed the craft along with its masts, yards, rudder, rudder hardware, and ten oars. This documents one of the earliest examples of shipbuilding in the oldest continually occupied port city in the continental United States.  Continue reading