Thanks Bob for posting the link to your excellent set of pictures re fitting
grips to Phillystran.
On a more general point I must say that I have never been entirely happy
with using grips on Phillystran. The grip is making contact with the outer
jacket and not connected to the inner bunch of fibres. What stops the outer
jacket parting and running down over the fibre core? I understand that this
is now the recommended termination method. We must therefore assume that
Phillystran have tested a quantity of terminations to maximum rated load and
found them to be satisfactory but I wonder what happens if the outer
covering is damaged on the tower side of the guy but close to the grip?
I recall that the termination method was different some twenty plus years
ago. The method then was to use custom Phillystran terminations and about
nine inches of the outer jacket was removed. The exposed inner fibres were
trapped in a two part epoxy type mixture, which was poured into the bottom
of the fitting. The outer jacket was not load bearing.
There is a similar guying product in use on this side of the pond, which is
called Parafil. http://linearcomposites.com/ap_com_masts_antena.htm It is
identical in appearance and feel to Phillystran. Their termination method
does not use grips but it does again trap the inner fibres in a custom type
termination. The method used is to remove the jacket and a tapered pin is
driven up into a matching tapered socket which traps the fibres around the
inner wall of the socket.
I did look into the use of grips to terminate Parafil (the custom
terminations are expensive) and I sourced a range of suitable grip sizes
from a friend in a utility company. I did some tests, which involved a
strong gate post and a 4x4. The outer jacket moved in my tests. I looked
into the differences between my grips and those that are recommended for use
with Phillystran. I noticed, from photographs, that the Phillystran types
were about twice as long as the ones I was using, which probably explained
the jacket slip in my test.
I would be very interested to hear if anyone else has reservations about
using grips with these guying materials.
Jerry Cahill/ EI6BT/EI7M
[mailto:firstname.lastname@example.org] On Behalf Of W3YY
Sent: Tuesday, November 11, 2008 9:30 PM
Subject: Re: [TowerTalk] wrapping a big grip on phillystran
You can see step-by-step pictures on my web site www.w3yy.com. The pictures
are contained in the Projects section under Phillystran. The direct URL is
http://www.w3yy.com/phillystran_assembly-1.htm That will be the first
picture. Click "Next Step" to see the next picture, etc.
73, Bob - W3YY
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