Here's an update on the Mercury snare. Since this was the worse drum out of all four, I decided to remove all the paint. Here are some pictures of the shell. The grain is very neat looking, but the patterns of the chipping/checking followed the grain. So it looks like something with the wood reacted to the paint.
There were up to 3 layers of paint. One white primer/base coat covering the entire shell inside and outside, then the silver coat on the entire outside and then the blue coat on the top and bottom.
I'll lightly sand the shell before I prime, but should I treat the bare wood with something to stop the checking from returning?
-Tim