The Mystery of Medieval Weapons & Armor – Where Did It All Go?
 

Certainly this is not new, but an interesting compendium.

https://www.warhistoryonline.com/ins...s-weapons.html

Article by Stirling Lundquest

No great mystery here....
Bronze was always recycled, and the demand for bronze cannon siphoned up huge amounts of scrap, to the point where very little old copper alloy of any kind survives.
Good blades were rehilted in current fashion again and again, and poor blades were again scrapped. The same with armour, a lot of plate was cut up to make brigandines and jacks, there is even 16th and 17th C paperwork from the Tower of London recording the process. Furthermore, there are pikeman's breastplates in the Leeds Royal Armouries that x-rays revealed to be triple sandwiches of plate where the middle layer is random pieces of obsolete armour. Breastplates also came out of the Tower in the 18th century to go to the Guards Cavalry serving on the Continent.
Finally there are the blast furnaces where scrap went in with the ore to help the process along. Again there survive paper records of old armour being sold off out of the great houses to go for scrap.
it's easy to forget that the scrap value of iron very often far outweighed any sentimental or antiquarian value of such once it was considered obsolete.