I have seen quite many 602 hihat tops with radial cracks crawling in from the edge - often not only one crack, but several.
In Denmark, a sole Sound Edge bottom is not worth much, as they are quite plentiful compared to complete hats.
Now, this alone doesn´t proof they are especially vulnerable - it could just be that they are on the market because a) people keep their complete hats b) they are not simply thrown out like cheaper bottoms would when their matching top cracks.
No proof.
But - I think they must be vulnerable, especially because of their pattern of not one crack but several.
As to why - they are generally rather thin, and most I have seen crack are Sound Edge tops. Now, that may be because they are the most plentiful, but could also mean that being on top of a Sound Edge bottom puts extra stress on the partly unsupported top.
There are not many thin 16 and 18" crashes left here - but were there ever many, at those prizes?
Zanki were a lot cheaper, probably more plentiful, and some are left. But they also tended to die at some time - maybe B20 is just a brittle material, that crystalizes at some point if treated just a little harshly?
Zildjian A´s are and were always more plentiful - how many of those have gone?
To me, the reason for percieved different survival rates could just as well be manufacturing differences in the hammering processes, in the tempering, in the exact alloy, in the shape the cymbals were given, in the (mis)use they were subjected to.....
I still haven´t seen any concrete pointers that the cracking - if it is more pronounced on 602´s than on other B20 series - should be because Paiste treated B20 in a way it wasn´t suited to be ("rolling it in one direction", "Stamping them out of sheets") and that differed from the other manufacturers, excluding the italians.
They differed by casting the bell too - but they also crack, so.....which cymbals doesn´t crack or crack markedly less?
Jon
