Loose rivets on zinc reed plates

[Big Squeezy Accordions]

Does anyone know why old style zinc reed plates often have loose rivets and misaligned reeds? Yes, they are generally older than the alumin(i)um ones but I've noticed that, even on accordions that have both zinc and alumin(i)um plates, that the zinc ones are more likely to have stuck/misaligned reeds. Perhaps zinc expands and contracts with temperature changes more than alumin(i)um?

 

[debra]

Zinc expands a bit more than aluminium but not all that much. Both expand much more than steel (alu about 2x, zinc almost 3x) but what is mostly a problem is playing under wildly different conditions (temperatures). Zink is weaker than "duraluminium" so when it expands it will become compressed by the steel rivets and when it contracts again the rivet may become loose. You can hammer the rivets again, but you have to be careful to not overdo it or the zink will deform. (Even aluminium will deform if you're not careful.)

 

[tcabot]

I suspect part of the challenge lies with initial riveting too.

Riveting a reed onto a brass plate is a lot easier than onto aluminium plate because the plate does not deform as much. Alu deforms more and the rivet loses its grip. If zinc plates are even softer, getting a good grip on the initial riveting is even harder.