Last week’s team effort on USS Monitor’s main engine

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The whole conservation team was busy doing some maintenance work on the USS Monitor main steam engine last week. It involved the following:
• draining the 20,000 gallons of solution, removing the stainless steel anodes and the reference electrodes
• performing a detailed conservation assessment of the engine
• thorough photo documentation of the current state of the artifact, and using these pictures to produce a 3D model of the engine
• cleaning the anodes and prepping new reference electrodes
• putting everything back in place and covering it all with a fresh caustic solution
We also were able to bring Museum staff members for a close-up view of this large object while the tank was drained. The perks of the job!
Below are a few pictures of the process for those of you who did not have a chance to check out our webcams or to come see us work live!

Now power is back on in the tank. The reference electrodes judiciously located around the engine will allow us to monitor the electrolytic reduction process in live time and to adjust the current if need be.

There is a Civil War Lecture this Saturday at 2pm: “Conserving Civil War Shipwreck: Research and Innovation”. It is free with museum admission. Come hear more about what we do behind the scenes!

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Mystery Object

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Mystery object’s x-ray

Hi all,

Among other endeavors, a mystery object was found within our collection. It is a lengthy, semi-oblong shaped concretion, excavated in 2001 in proximity to the engine room of the Monitor. It has been stored dried for a while, and a recent look at it showed that at least four straps of leather were intertwined within the hard mixture of corrosion products and calcite. In addition to the leather, a couple copper alloy ornate buttons were also identified. A few X-rays were performed in-house last week to attempt a better identification of the object. Unfortunately the thickness of the concretion did not allow for a very clear image. See for yourself:

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The port Dahlgren gun carriage is fully disassembled!         

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Details of the bottom plates, friction plates and friction rollers. View from below and transverse section. Peterkin, 1985.

Last week Will was able to escape his desk for a few days and help take apart the last elements of the port gun carriage.

The complete braking mechanism was still in place, but by separating all of the parts  we are able to maximize the amount of salts extracted from the artifact down the road (aka: a conservator’s dream!). After studying the historic blue prints (see historic plan below), we knew that one piece was the key to this puzzle. We also knew that we would need access to both the upper- and under-side of the carriage. In order to gain access to both, Will custom welded a rig allowing the artifact to stand vertically during treatment.

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Quick Lab Update

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Last week, dry ice cleaning was performed on the port gun carriage’s wrought iron frame. This is the second time that this object has been cleaned with this technique. The first time was last spring and the carriage has been under electrolytic reduction since April. Speaking of electrolytic reduction (AKA “ER”), we often mention it but rarely explain the method. This is a stabilization technique that is used every day in this lab (and broadly in the field of conservation) and we can forget that it is not a simple matter… Our website has a great animation to illustrate the process, check it out here!

Last Wednesday was quite an exciting day for the team as we had fellow East Coast archaeological conservators visiting for the entire day! Nichole Doub from the Maryland Archaeological Conservation Laboratory, Johanna Rivera from the Clemson University Restoration Institute (working on  the H.L. Hunley in Charleston, SC) as well as Emily Williams from The Colonial Williamsburg Foundation were introduced to the joy that is dry ice blasting. Our project manager, Will, worked to establish the ideal parameters to clean wrought iron artifacts from the USS Monitor collection with dry ice over the last few years. During our colleagues’ visit, he shared the process that has been developed here and advised them on the procedure to follow, should they decide to invest in such a cleaning tool in the future. The day resulted in many nerdy conservation discussions regarding the original surface of artifacts, active corrosion processes and other pH related questions. Thrilling!!

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