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Okeanos
01-09-2011, 10:16 AM
A friend of mine recently recovered an Elizabethan cannon from a site where there is no wreck. We've found out quite a bit about it so far but due to it's size, preservation is a problem. The cast iron has gone very soft, it'll never be as new but we can slow it's decay. A few years ago I wrote an article about preservation based around, and quoting the procedures used on the Mary Rose preservation techniques.

The article I wrote is - http://www.atlanticscuba.co.uk/index.php?option=com_content&task=view&id=152&Itemid=28. Since then I have tried several things and found Bituminous Paint to be the easiest and best.

With the cannon, he's put it in a huge stainless steel bath and is monitoring the ph level. As and when the solution shows any sign of turning acidic he adds caustic soda to raise the ph again to keep it as close to neutral as possible.

A pic after the encrustation has been removed.
http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs1356.snc4/162847_10150358277385302_692695301_16318948_199017 6_n.jpg

The Publisher
01-09-2011, 07:02 PM
That has to be worth quite a lot!

As to preserving submerged cast iron, I found this:

www.ndt.net/article/art2008/papers/093Bartuli.pdf

Okeanos
01-10-2011, 05:12 PM
That has to be worth quite a lot!

As to preserving submerged cast iron, I found this:

www.ndt.net/article/art2008/papers/093Bartuli.pdf
The problem with the cannon is the state it's in and unless provenance can be shown it's not worth a lot.

The above article is interesting but is for in water preservation, you'll still have the same problems if removed from the salt water environment.

The Publisher
01-10-2011, 11:17 PM
Sort of doesn't do any good to let the masses see and enjoy this sort of historic thing in a museum setting if it has to stay submerged. :(

acelockco
01-11-2011, 06:30 AM
It could always be kept in a clear display filled with water, like a fish tank.

Okeanos
01-12-2011, 04:37 PM
It could always be kept in a clear display filled with water, like a fish tank.
It rusts like crazy. As the chlorine ions are released it turns the water acidic, which eats away the the metal. Adding caustic soda returns the solution to neutral. The smell is also something quite unpleasant.

It had to be lifted for dating detail. We are trying to find out if there is a wreck around. There are no records of a wreck of that age in the area. Recovering items will help with dating and maybe identify the wreck. Professional conservation costs too much and there are no official bodies interested as the wreck hasn't been identified. If we can find out what it is we may get official bodies involved but more than likely they won't bother as we have so many wrecks of similar age. It is unlikely to be of major importance dues to the size of cannon, ships of the line would have 32lb cannons. Even a 4th rate frigate like the HMS Colchester (1694), which we are looking for, had 50 x 32lb cannons.

acelockco
01-13-2011, 05:45 PM
OK, a clear enclosure filled with clear oil, that will prevent any rust, keep hands off it, and will preserve it.


Although if it is of no importance like you say, just wash it with some soap and water and a wire brush, get some good spray paint, make it look all nice and plop it on your front lawn.

Okeanos
01-13-2011, 05:52 PM
OK, a clear enclosure filled with clear oil, that will prevent any rust, keep hands off it, and will preserve it.


Although if it is of no importance like you say, just wash it with some soap and water and a wire brush, get some good spray paint, make it look all nice and plop it on your front lawn.
Both of the above will work although my preferred method would be the latter :D