Copper means NOTHING by itself acoustically speaking. We need to know if the copper is annealed or tempered, where it is braced is significant, the thickness of the material also is a big factor. It looks cool is the major purchasing decision. Then we talk our brains into believing what the eyes see. I am not saying that copper is no good. I am saying that the trumpet is a system made up of many pieces that ultimately influence the sound. Isolating one factor is meaningless. If your copper turned silver when the laquer came off, then it is not copper. It is probably nickle silver. Josef Rudall was the oldest maker in the UK. They started as Rudall Rose Carte and Co in about 1780. It became Rudall Carte in 1872. The company was bought by Boosey and Hawkes during WWII.