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British Historic Cannonballs
4

British Historic Cannonballs

British Historic Cannonballs

(OP)
Any suggestions on how to keep the cannonballs from corroding on exposure to air?

From the BBC:

The Mary Rose sank in 1545 and was raised from the sea in 1982. The cannonballs on board are difficult to conserve because chlorine has got into them from being in the sea. The chemical has got in all the way to its core. This means that they start to corrode if they are exposed to the air.

Dr Schofield's team has tried to remove the chlorine by soaking some cannonballs in solution. But the researchers found that although they had extracted some they hadn't removed it all. They discovered this when the cannonballs began to disintegrate when they were put on display.

http://www.bbc.com/news/science-environment-433347...

Dik

RE: British Historic Cannonballs

Remember reading an article about the conservation of the Hunley artifacts. The procedure is outlined in this article. Don't have an update on the procedure but would expect that it would work for the cannonballs as well.

Hunley

RE: British Historic Cannonballs

Such extensive corrosion would not have all happened after exposure to air, but I don't doubt that whatever has gotten in through the cracks could be difficult to remove.
To paraphrase Monty Python, this is an ex-cannonball.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: British Historic Cannonballs

(OP)
Thanks, gentlemen

Dik

RE: British Historic Cannonballs

(OP)
bimr:
Sent your info on to the MaryRose.org

Ironic metallurgist:
Sent your info on to John Cleese

thanks... Dik

RE: British Historic Cannonballs

Why display them in air? There must a suitable neutral transparent fluid that could be used. And even ex-parrots can be mounted for display.

RE: British Historic Cannonballs

(OP)

Quote (stevenal)

Why display them in air?

Should have replied... thanks for the info... have passed it on, too.

Dik

RE: British Historic Cannonballs

I maybe stupid but if the cannonballs have been preserved in low oxygen seawater for so long, maybe keeping them into the same environment will avoid further corrosion ?
what about coating with resin ?


RE: British Historic Cannonballs

(OP)

Quote (chumpes)

what about coating with resin ?

Sent the information about displaying them in a fluid and added the suggestion of a coating system... heard nothing back from them. From the photos of the deteriorated cannonballs, I would never have guessed that they would have deteriorated like that...

Dik

RE: British Historic Cannonballs

Quote (Chumpes (Petroleum))

I maybe stupid but if the cannonballs have been preserved in low oxygen seawater for so long, maybe keeping them into the same environment will avoid further corrosion ?

That is generally what is typically done, to maintain the item in storage until the item undergoes conservation.


Quote (Chumpes (Petroleum))

what about coating with resin ?

Problem with this solution is that exhibit visitors want to see the real thing. You could also show images of the item too, but exhibit visitors want to see the real thing.

RE: British Historic Cannonballs

I recall that they have used electrochemical treatments to recover encrusted and heavily corroded artifacts.
The fact that these are intact as found and only crumble on exposure to air tells me that it is the oxidation of the internal phases that are driving the destruction.
Perhaps an applied electrical current while submerged in hot water would be a way to 'de-tox' these.
I presume that a sample has been core drilled from one for detailed chemical and structural analysis?
Sounds like a job for someone working on a PhD in electrochemistry.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: British Historic Cannonballs

(OP)
EdStainless...
Will pass that info on...

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