[TowerTalk] polyrod

[Tyler Stewart]

Let's hope that is true today, but it certainly wasnt true with the first 
batches of the stuff we put up.  It's been what...10 years or so since I put 
together what may have been the first ever order from Polygon for hams and 
it was a real PITA.  Some of the coils sat around for a few months and when 
we went to move them out, etc., we found lots of fractures and some complete 
breaks.  We had to trash a lot of it and they replaced it after we sent back 
samples of the breakage.

If it were mine, I wouldnt let it set around a long time in a coil, no 
matter what the sales people tell you.  It's got to be stressful on the 
glass fibers and the resin, especially if it's left out in the sun as a 
coil.  Black fiberglass gets very hot in the sun if it doesnt have air 
circulating around it.  Add the stress of being in a coil...  no thanks!

The problem stems for the fact that glass fibers in compression are not very 
strong, but very strong in tension, and the resin is just there to bind the 
fibers together and adds no real strength.  So when you bend a fiberglass 
rod, the fibers on the outside of the bend are forcing the inside ones into 
compression.  Once the inside ones start to fracture in compression, it's 
neighbors toward the outside start to fail as well... pretty soon you end up 
with a major fracture or complete breakage...and you are trusting your life 
to this stuff when you climb your tower.  It's just not a smart thing to 
do...dont tempt fate!

Ty K3MM

----- Original Message ----- 
From: "Tom Rauch" <w8ji at contesting.com>
To: <keith at dutson.net>; "TowerTalk" <towertalk at contesting.com>; "Pete Smith" 
<n4zr at contesting.com>
Sent: Saturday, April 09, 2005 11:48 AM
Subject: Re: [TowerTalk] polyrod


>> I hope that one of the guys locally who were involved in
> the first PVRC buy
>> will comment on this, but I understand that the rod cannot
> be stored rolled
>> for a protracted period -- something about migration of
> fibers in the resin
>> matrix?
>
> I'd ask polygon.
>
> I did that and the engineer at Polygon told me that's
> nonsense. So did sales people.
> They tell me they often store rod coiled up for many years,
> sell it, and have no problems at all.
>
> Keeping that in mind, I've had some laying against a fence
> in the sun for three or four years now and just uncoiled one
> roll a few weeks ago. It was perfect.
>
> 73 Tom
>
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