Ive a friend that is making a replica of the Iron age Battersea shield, found in the river Thames in Victorian times. Now he and I have been discussing his problem . That is the original alloy used was copper tin 90/10. by percentage anlysis. In other words 9 parts of copper to 1 part of tin by volume Now he made up his alloy by weight . ie say 18 0z of copper to 2 0z of tin. He carefully melted the copper and added the tin, cast his ingot, cleaned it up and proceeded to hammer it out into sheet. It always cracked, despite repeated annealing. So I said because tin is lighter than copper your in fact adding more tin than 10%. If you want a 90/10 to finish up with, you have to do the alloying by parts. Ie volume . I said you need say 9 1in cubes of copper to 1 1in cube of copper to get the 90/10 result. He couldnt see that. Now I put this to the scientific minds on REc. Crafts. Metalworking to resolve, one way or another which is the right way to make this alloy. This is not a scam or a troll. What eventually happened as he had a deadline to finish it I gave him som 70.30 brass sheet that was the same colour and was ductile enough to do the replica. Ted Frater Dorset UK.
- posted
13 years ago