I haven't reviewed all the background info, but..
I've been using 6700 Phillystran for years on both a 100 and 120ft tower
with big grips. So I don't understand the current discussion.
See the link below:
http://www.w3yy.com/Phillystran.htm
I also used the smaller version for boom truss support and it worked great.
73, Bob - W3YY
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Grant
Saviers
Sent: Thursday, October 22, 2015 9:43 AM
To: Roger (K8RI) on TT; towertalk@contesting.com
Subject: Re: [TowerTalk] [Bulk] Re: Phillystran
Roger,
I think you should read the Phillystran docs a bit more carefully, see my
prior post for links. Philly is still terminated with a Spelter like
socket. Big Grips are available on the lower strength guys (except 1200).
From the specs: "The Corona Sockets are aluminum, resin filled, potted end
terminations and are always factory installed." Available at the
1200 size and larger, although not for every break strength cable.
If you read my NCJ article, it is about older Philly that must be terminated
with epoxy filled sockets, Big Grips do not work on any size. However,
according to my discussion with Phillystran engineering, they do not sell
the sockets any more except to the military and perhaps special contractors.
Also, the factory epoxy is not available in the USA even though it is in
catalogs. With about 1500' of 25k old Philly on hand, I was in search of a
full strength and reliable termination technique and proved it with
extensive long term tension testing and testing to failure.
They changed to Big Grips on the smaller sizes when they changed the core
design from parallel strand Kevlar fibers to that similar to conventional 3
strand stranded rope, although there are more strands of Kevlar in current
Philly.
Anecdotes, "my boom hasn't bent yet" are interesting, but show me the
tension test data for saddle clamp terminations that were installed a few
months ago.
I still have my tension tester, able to generate 20k lbs tension and someday
might get around to some more tests.
Grant KZ1W
On 10/22/2015 0:26 AM, Roger (K8RI) on TT wrote:
> This should not be a factor where the Phillystran is used as a truss
> at a fraction of its strength. As guy lines the standard "Big Grip is
> recommended. They haven't used Spelter sockets and epoxy for some
> years even on the larger 6,000# cable.
>
> For a truss 3 saddle clamps are used with the saddle on the live side
> (never saddle a dead horse) so creep has never been a problem when
> used on a truss. The Big Grips (Recommended by Phillystran and sold
> by vendors) grip entirely on the jacket, but it's over about 18" or
> more. If you wrote a recent article recommending Spelter sockets, it
> is not what the manufacturer recommends, hence they have not been the
> proper method of termination for a number of years. I don't know when
> they changed, but it was Big Grips in 2002, or 13 years ago when I
> installed my 45G using Phillystran's recommendations. I didn't find
> any sellers of Phillystran even offering Spelter sockets.
>
> Follow the "Prime Directive"
>
> 73
>
> Roger (K8RI)
>
>
> On 10/21/2015 11:35 PM, Grant Saviers wrote:
>> I strongly advise against saddle clamps. The problem is creep of the
>> plastic jacket causes the clamp force to decay with time. Until the
>> clamp completely cuts through the jacket the clamp force decays. At
>> room temperature it took about 3 weeks and at least 4 tightenings to
>> get the saddle to cut through the jacket. I used a torque wrench to
>> set the tightening force and measured the residual torque at a late
>> time each cycle. I built a tension tester and verified saddle
>> terminations will slip well below the breaking strength of the
>> Philly. Even after 121 days and 4 tightening cycles the saddle clamp
>> torque values indicated continuing creep and reduced termination
>> strength. I was unable to achieve more than 30% of the break
>> strength of the Philly. (25000# Philly and 7000# load for slippage).
>>
>> Later I tested the proper terminations for this Philly (Spelter
>> sockets with epoxy) on a commercial 100,000# tension test stand and
>> the guy failed at 28000# tension and not the termination. See NCJ
>> Nov-Dec 2014 for my article.
>>
>> I've seen bent booms as a result of using saddle clamps. I also
>> found them loose on my steppIR 4L after a year on the 1200 size so
>> will never use it again.
>>
>> Phillystran says use grips on all 2100 and larger. Follow the
>> directions!
>>
>> Grant KZ1W
>>
>> On 10/21/2015 13:06 PM, Mike Reublin NF4L wrote:
>>> Mostly what compresses is the jacket. No strength is lost. My
>>> SteppIR uses Phillystran (as a bridle) with small saddle clamps. The
>>> PS is very flat in the clamps.
>>> 73, Mike NF4L
>>>
>>>
>>>> On Oct 21, 2015, at 3:46 PM, GMuller885--- via TowerTalk
>>>> <towertalk@contesting.com> wrote:
>>>>
>>>> All:
>>>> Thank all of you for the input. Based on all the input my
>>>> guys and
>>>> stays are of Phillystran 6mm dia 2100 lbs break strength. I am
>>>> using guy line clamp kits, three to a connection. The only
>>>> question left is that if the Guy cliompress the Phillystran how
>>>> much strength is lost if any?
>>>>
>>>> Gerald Muller K9GEM
>>>> GMuller885@aol.com
>>>> _______________________________________________
>>>>
>>>>
>>>>
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