Mystery object: part II

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Cross-section of the concretion showing stacked straps of leather.

Thanks to Riverside Regional Medical Center, our “mystery object” received a CT scan a few weeks ago!
We are so grateful for the help our health care neighbors provided with the project.
Also, thank you all for the many suggestions last month on what could be trapped within this concretion!
So… what did we find?!
A whole lot of precious information for conservation purposes!
First of all, the CT scan confirmed that any metallic material left within the concretion is fully mineralized, in other words, there is no more metal left, only metallic corrosion products.
Second, we now know that there is a LOT of leather left inside this concretion. The object is composed of many leather straps, sometimes up to 7 of them stacked on top of one another. See these pictures of cross sections of the concretion:

In the following picture, an o-ring can be seen from which at least two small straps depart (yellow arrow). On one of these straps, stiches can be seen (red arrows).

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And we’re off. . .

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Hannah taking the photos she needs to create the 3D model.

Our spring/summer season is off to a busy start. The week before going into the engine tank, we were in the condenser tank. No cleaning or disassembly took place. This draining was to perform maintenance and examine the artifact. We removed and scrubbed the anode and changed the reference electrodes. The condenser itself is in great shape. See photos below. It is now happily back under electrolytic reduction in a brand new sodium hydroxide solution.

Hannah took a ton of photos and using photogrammetry software was able to create a 3D model of the condenser. It looks fantastic. You can check it out here.

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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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Featured: A Union Spy

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Happy Women’s History Month!

I realize that this is the last day of March and that makes this write-up a late celebration of the heritage month. But, to be completely honest, I really struggled with how I wanted to approach this blog. There are so many awesome women and deciding on one story to share was incredibly difficult.

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