Answering Matthew Caulfield and Robbie's remarks yesterday about the
use of shellac with carbon-black (78 phonograph record material) for
spool flanges.  Most good 'plastic' flanges in the early days were
made from Bakelite or hard rubber.

Bakelite (phenolic thermosetting resin with carbon black and other
fillers) and black shellac are completely unrelated.  Old ground-up
78-rpm records could work in injection molding machinery, but the
result would be pretty flimsy.

This thread gave me an idea about the fragile flanges used by QRS
during and after the war.  No doubt many subscribers have noticed how
easily the flanges on these rolls break.

A simple test demonstrated that these flanges were indeed made
from shellac based compound, or something very like it.  Taking an old
J. L.  Cook wartime re-issue roll with a broken flange, I applied some
heat with a cigarette lighter to the flange, and it became softened
very easily.  This can not happen with Bakelite, which once set, will
not melt and will burn only with great difficulty.

Other meltable polymers available during that time, such as PVC or
polystyrene, were costly and hard to get then.  Also, they behave
differently when flame is applied: charring, smoking and dripping,
rather than just getting soft.

Thanks for clearing up a matter that has puzzled me since I first
started ordering QRS rolls from Imperial Industrial in the 50's.

Richard Vance