I'm using standard fiberglass reson. The white stuff is fiberglass sheeting. Its used for building shower stalls. Its about 1/16" thick.
I've had some scraps left over from some other projects. Since its allready fiberglass, its very strong when stacked up and glude together as laminations.
Its very easy to cut with a router circal cutter. I use a scrole saw to cut the shape and location for the coils. I drill holes through the edge to form the coil wire exit.
This formate keeps the coils in the proper position and location (no drifting).
The amount of reson is reduced a bunch. I also use the sheeting as a magnet template. I leave this template glude to the steel disc perminatly.
This stator will be secured to a 12" speaker basket. This gives the stator 360 degree support. This whole asembly is very light but very strong. The speaker baskets makes a perfect mount for the bearing and shaft assembly.
JK TAS Jerry