Hi Juaort,
I examined the Sonoc bell again, and I couldn't find a single trace of welding. The flanges overlap and have been
riveted with four rivets on each side. Only at the handle the edges are soldered and filed to provide a comfortable grip, or rather to prevent the player from injuries. The material is relatively soft, heavy and about 2 mm thick. As can be seen, the bell is chrome-finished.
Actually you had to expect some buzz or rattle from a bell that is only riveted, but this is not the case. However, I haven't used the bell a lot; perhaps it would develop an unwanted noise after long and extensive playing. By the way, the bell is anything but precision-made. And it is not exactly easy to hold. As I said already, it has some disharmonic overtones. It is a bell that you don't want to open too much. It sounds best when gripped tightly and kept muffled. Then it has that dry and funky sound that I know from contemporary Cuban Son bands.
Interesting that they made cowbells from car bumpers. By any means, I can't tell you what this bell had once been made of. I think Cubans could take a single bumper, repair it and turn it into a driveable vehicle again
The LP bell in the middle of my photo is the so-called "New York" model bongo cowbell LP206C. It has a silvery grey finish with a hammered look. I don't know whether it's paint or whatever.
Greetings,
Thomas