Like the Sonors, Zildjian Noble & Cooley, etc. This drum is sand cast from melted bronze. Not an easy task. As a drum builder I've been looking at melting my old cracked Z's into a shell. Finding out it there is more to it than just melting the metal and pouring into a mold. If it's not done right, you can have air bubbles known as tearing, or worse, the metal cooling before completely filling the mold. Having talked to N&C about the original Z shells, the metal doesn't do well when melted a second or 3rd time. So I'm trying to get it right the first time. It's no wonder Tama, Sonor, & Ocheltree charge $2500+ for these drums......And Calf, there is a huge sound difference between a rolled/welded shell and a casted shell..
Good luck with that, I wouldn`t do it, I`d go to a small Foundry !! Not only will you have the porosity factor but copper will start to burn off waiting for the tin to melt and your mixture will change if you don`t add copper while melting. You gotta know those percentages and figures, if not leave it to the pro`s !!