I have been meaning to write a blog about progress on the Monitor ropes but, although archaeological objects conservators are currently focused on this part of the collection, we do all sorts of other things that I thought would also be interesting to share with you.
“Rust never sleeps” was the title of an ICOM-CC conference dedicated to metals conservation in 2011; and it summarizes quite well why the conservation department cannot just leave the lab completely unattended during the current pandemic.
Not only are there a lot of electrochemical treatment set-ups that need constant attention in the “wet lab” and outdoor tanks, but environmental conditions in dry object storage also require our steadfast attention.
When the US Navy and NOAA archaeologists decided to recover the emblematic Monitor gun turret from the ocean floor, the entire engine room was in the way and therefore had to be recovered first. This included the main engine, ventilation engines, auxiliary pumps and the condenser. Now, in order to conserve these complex pieces of machinery, a large part of our job is to disassemble them. This allows for appropriate treatment of the different materials (iron, copper alloys and gaskets have different conservation requirements), while more exposed surfaces provide better extraction of harmful salts and thorough surface cleaning. Disassembly can be quite time consuming but there is no way around it! In 2019, one of the conservation team’s projects was to further disassemble the condenser (yes, parts had already been separated).
But first things first, what’s a condenser condensing and why?!
Condensers were invented in the late 18th century by a Scottish gentleman, James Watt, to make steam engines run more efficiently. Such engines used water properties to activate pistons. When steam (water in a gas form) located in a cylinder is quickly cooled and turned back to water (condensed), it takes up less space than in its gaseous form which creates a vacuum in the chamber. As a result, the piston is first pushed in one direction before being pulled back in the other direction when a vacuum is created by cooling down the steam. Originally, in order to create this vacuum, water was sprayed directly on the steam within the piston chamber. It worked well but overall wasted a great deal of energy by repeatedly cooling and heating the cylinder. James Watt therefore saw the need for an external piece of equipment, a “condenser”, where steam would be condensed away from the piston chamber. The addition of this device rendered steam engines faster, more efficient, more reliable and more economical… And consequently condensers were used in different configurations in all marine condensing engines through the mid-19th century.
It has been too long since we’ve given an update on the conservation of Monitor’s port gun carriage. So long in fact, that the conservation of its 250-ish components are now complete!!!
Looking back and reflecting on the many steps of this (large) object’s treatment, I really love that it has benefited from all of the research and discoveries done in the lab over the past 10 years. It is, after all, the largest Monitor object completed thus far and we were experimenting a lot along the way to provide the best treatment possible with current knowledge. We also knew that the work would benefit not only “our little Monitor” but the field at large. And we learned so much!
We have been working on a few large items in the Wet Lab recently. One of the ventilation engines needed a new support, which required flipping the object 45 degrees, and custom building a frame for this purpose. Additionally, a second round of dry ice blasting was applied to the port gun carriage and a first round of dry ice cleaning was performed on a section of the propeller shaft.
We just wanted to share a few pictures from all processes, so here are views of the ventilation engine re-support:
Here are a few before and after from dry ice cleaning of the port gun carriage: