Yesterday I did some transfers of 3.75 half track stuff made in 1951. They
were all 600' on original 5" reels with frighteningly small cores. Until a
few years ago, they had been kept in a closet in a house: thankfully not a
garage, attic or basement. They were subsequently moved to a proper (cool &
dry) environment. The stock was 3M 111 & the only problems that occurred
were the spots on adjacent layers near splicing tape. Each tape played
right to its physical end, having been recorded that way because they never
had that great old paper multi-color leader / timing tape applied to either
The only deformations were towards the center: periodic depressions caused
by the very wide threading slots on the cores.
It's a kick to encounter such stability of a 50+ year old synthetic product
that not too long ago, was regarded as inferior to ostensibly state of the
art counterparts made 25 years later!