On 05/12/19 14:45 PM, Richard (Rick) Karlquist wrote:
Yale Cordage, in some of their high strength ropes, uses what they
call UHMWPE (Ultra High Molecular Weight Polyethylene), which they do
NOT identify as Dyneema. They have manufactured these ropes for a long
time...I'm guessing they make the fiber themselves, or they would call
it Dyneema.
Although Dymeema may be made from UHMWPE, it is considerably different
from run of the mil UHMWPE. UHMWPE has a coefficient of thermal
expansion (CTE) of 220 ppm, and machines easily. Dyneema has a NEGATIVE
CTE (very rare), and is very difficult to machine. These
characteristics don't necessarily translate to good rope, but they
at least differentiate it from ordinary UHMWPE.
Makes sense, I didn't dig very deep.
What makes a 'good' rope is a fascinating topic. I've been tempted in
the past to try out some of the exotic types to use in the tower biz,
but knowing that it will be dragged over barbed wire the 1st time it's
used has made me back off on that.
-Steve K8LX
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