Hello again, Alan. I disassembled and cleaned the entire melodica and after mounting it, the leak continued (not expected something very different, actually). It seems that I have to replace the gaskets and probably I will use a different material from that one that melodica originally has. I usually use an adhesive-backed stripping, just like as you suggested, but here in Brazil the thinnest has 2mm (1/13”, i think) which compared to the one that the melodica has, would be thick. I am afraid that if I use it, it may misalign the holes of the air chamber in relation to the key mechanism. Also I’m not sure if the current leak comes only from the air chamber, it might also come from the keys already. I also took the opportunity to align the reeds gap and, even with the leak, they are responding well. What a wonderful sound! I love that timbre! I hope I can solve this leak so that it works perfectly.