Medieval sword - opinions needed

[Raf]

Originally Posted by AHorsa

Here is a sword with a similar patination. Sadly there is no background information on it:

Probably the only way to establish the authenticity of your sword is to understand how these extreme patinas on fake medieval swords are created. Which I assume involves reversing the process of electrolysis used to de rust authentic archaeological finds. This involves dumping the fake sword in a bath of water and washing soda , hook it up to an arc welder and stand well back . The sword is connected to the positive side of the power supply and the negative side to iron plates suspended in the solution. Negative ions (oxygen ) are attracted to the anode, the oxygen combines with the iron and forms the rust. The longer the process or the higher the amperage the more of the iron is etched away. Once pitting has begun some complicated metallurgy takes place which means the pits get deeper creating the irregularly surface associated with genuine decomposition of an iron object. I hope this explanation is in principal correct but if it isnt I’m sure someone more knowledgeably will correct me.

So far so good. The sword will have an orange rust surface which is unlikely to be convincing unless its being offered as a recently excavated find. Options then are to revere the polarity to strip off the recently acquired rust in which case the appearance will be an object that has been electrolytically cleaned. Alternatively remove some , but not all of the rust and use a rust converter (tannic acid) to chemically convert the reddish iron oxides into bluish-black ferric tannate, a more stable material associated with old well established rust.

Rather than comparing the patina on your sword to authenticated examples it might be useful to compare it to the patina on obviously faked examples . A trip round the net will provide plenty of spurious objects that have been aged in this way . Bradfords auctioneers has some good examples of genuine fake medieval swords and helmets. It might be possible to see if there are any minute differences between naturally occurring and electrolytically simulated ageing that might tip the balance one way or other.