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The Cannon Project

November 4, 2010

The June cannon pour

Cannon pourThis June’s attempt to pour the light three ended in disappointment. It is pretty obvious that the bronze “froze” at the inside end of the tap hole as it started to flow. It wasn’t hot enough to run—that was one problem at least. There might be others we have not yet uncovered.

We have begun to disassemble the furnace to see if we can determine what happened and what we need to do to correct the problem. So far, we have removed masonry down to the tap hole and sectioned the tap hole itself.

Over the next few weeks, we will be getting further into the furnace structure to see what else might be revealed and to figure out how to remove the 500-pound mass of bronze that remains in there.

We have not yet removed the molds from the ground—something we will have to do to prepare for the next pour. The molds were almost certainly damaged by an afternoon downpour the day of the pour, and we are not going to re-use them.

The founders are in the process of making a whole new set of molds while the weather remains good this fall. Much of this is an outdoor activity, and we want them to be complete and ready to use when we are set to make another attempt early next spring.

Over the winter, with new information in hand, the masons and founders will determine what modifications should be made to the furnace to increase its heating capability and any other problems associated with it. They will rebuild/modify the furnace next spring when weather and time permit, and another pour will follow shortly.

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  1. May be i am missing some thing here; the light 3 pdr has a finish weight of approx 220 lbs so why the need to heat up 600 lbs for the pour?

    • Thanks for your question. The foundry team cites two main reasons: The barrel is poured as a solid piece and then bored, reducing the final weight of the casting significantly. Secondly, there is a massive “dead head” in the top of the mold. This fills with molten metal after the barrel portion of the mold is filled and provides additional metal to the mold portion as the bronze cools and shrinks. The dead head is later sawed off the barrel portion of the casting before any other boring/finishing work is begun.

      • Thanks for your reply…makes sense to me now. If at first you don,t succeed try try again! Good luck its not called an occult art for nothing.

  2. Take a look at these guys on youtube. Granted, they are using modern methods, but maybe they can give some suggestions.

    Springfield Arsenal LLC

    http://www.youtube.com/watch?v=SAomnhzif7w&NR=1

  3. Any new new attempts or updates coming up?

    • We are hoping to make another pour this autumn. The molds are pretty much ready to go, but we had to disassemble a large portion of the furnace in order to retrieve the bronze that solidified in it after the last attempt.

      The furnace has yet to be rebuilt because the Historic Trades masons are spending most of their time working on the Public Armoury project, but we hope to free them up to do the work within the next several months.

      The rebuilt furnace will incorporate some design changes that will improve its operation. In the meantime, a modern foundry is remelting the lump of bronze for us and will be able to get it back to us as ingots. As we are able to pin down a tighter schedule, we will post the information.

This project is possible through a generous gift by the Ambrose and Ida Fredrickson Foundation. Research assistance was provided by Firepower: The Royal Artillery Museum, and the National Park Service. We are grateful to the Museum Restoration Service and The Royal Artillery Historical Trust for the use of their images.


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