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College of Arts & Sciences
Maritime Research Division

EXCLUSIVE: Conservation of Associated Artifacts from the CSS Pee Dee Cannons

By Johanna Rivera, Warren Lasch Conservation Center

     In September 2015, approximately 40 artifacts and samples associated with the CSS Pee Dee cannons were brought to the Warren Lasch Conservation center, along with the cannons, to be conserved. These artifacts were found inside the IX-inch Dahlgreen, VII-inch and VI.4-inch Brooke rifles. They range from iron grapeshot to wood and textile fragments.

The grapeshot came in 2 groups, one from each of the Brooke rifles.  One stand of 11 balls from the VI.4 inch Brooke rifle and the other group with 12 balls from the VII-inch Brooke.  Most of the shots from this last group (Right) were covered in textile fragments. The textile was most likely from the canvas bag holding them in place inside the cannon. Since the treatment used for cellulose based materials it’s completely different than the treatment used for metal artifacts, the textile that had to be removed before placing it in the chemical solution. The textile was removed using dental tools and separated in six groups. Their locations were recorded so once conserved they could eventually be placed back on the shots. The textile is a very sturdy cotton canvas with some remnants of cotton stitching.

Other metal artifacts from the cannons, included a wrought iron grape stand from the VI.4-inch Brooke, an iron nail and a cast iron cannonball from the IX-inch Dahlgreen. These artifacts were photographed, catalogued and placed in a caustic bath for the removal of chlorides. It is important to mention that since the provenience of the PeeDee cannons is fresh water, the salt levels within the metal is very low, therefore their treatment is significantly shorter than materials recovered from salt water.

The cannonball from the IX-inch Dahlgreen also had a copper alloy fuse associated with it. The fuse (Left) was analyzed using X-ray fluoresce (XRF) in order to identify the elemental components identifying it as bronze. The artifact was cleaned using sand blasting, rinsed and then stored in a high pH solution for the removal of chlorides.  

In terms of organic materials, the iron stand from the VI.4-inch Brooke cannon had a large fragment of the gun powder bag still attached to the base. This fragment also had to be removed in order to begin the chemical treatment. The cotton bag was cleaned using a gentle water stream and ultrasonic bath to remove any remains of gunpowder. Although most of the gunpowder has been reduced this way, it will be impossible to completely eliminate it since it is embedded within the fibers. The fragment has been stored in a chelating agent solution to make sure we remove as much as gun powder as possible.

One of the most interesting artifacts received, was a wooden sabot recovered from the IX-inch Dahlgreen. The sabot (Right) was covered in gunpowder with some remains of the iron straps. The sabot was cleaned using dental tools, and the straps and a nail were removed and treated separately since they were made of iron. The sabot was first treated using a solution of a chelating agent for initial cleaning for a couple of weeks, then it was rinsed using an ultrasonic bath and kept in de-ionized water for a week. It was then submerged in an acidic solution for the continuation of the cleaning which will help to eliminate most of the gun powder.  

All of the artifacts are still undergoing treatment, and due to their fragile nature it might take months before they are fully cleaned and ready for exhibit. Since these materials are coming from an underwater environment, the care post-treatment will have to meet certain requirements in regards to humidity levels, light and temperature in order to avoid any problems in the future.   As the conservation process progresses, we'll continue to provide updates on these fascinating pieces of history.