Slightly zombified thread drift:
This is the first I've heard that L-2s or XL-2s used powdered graphite. I was always under the impression that Steinberger used graphite thread running the length of the instrument. From my understanding of carbon fiber construction this would seem to be the only way for the graphite to impart any controllable/predictable strength to the composite structure; powdered graphite would be homogenous to a fault (i.e., not contributing strength in any particular dimension).
While Steinberger went for a solid, molded mix of resin and powdered graphite, Green build lightweight cores out of plastic foam (originally out of balsa wood, as I understand it), and covers them with layers of resin-soaked woven graphite cloth, a lot like the way surfboards are built.
This is the first I've heard that L-2s or XL-2s used powdered graphite. I was always under the impression that Steinberger used graphite thread running the length of the instrument. From my understanding of carbon fiber construction this would seem to be the only way for the graphite to impart any controllable/predictable strength to the composite structure; powdered graphite would be homogenous to a fault (i.e., not contributing strength in any particular dimension).