texascavers Digest 23 Jun 2014 16:08:35 -0000 Issue 1998
Topics (messages 23970 through 23977):
Re: Kevlar related
23970 by: Kevin McGowan
23974 by: Don Cooper
23976 by: Mark Minton
23977 by: Espeleo Coahuila
Re: Question..
23971 by: Bill Bentley
23972 by: Geary Schindel
Internet related
23973 by: David
Amazing 3-D Tour of a Chinese Supercave
23975 by: Lee H. Skinner
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----------------------------------------------------------------------
--- Begin Message ---
I use Kevlar for the foot loop on my frog system for years. I worked great.
KM
Sent from mobile device
Kevin McGowan Photography
5250 Gulfton, Suite 2F
Houston TX 77081
Studio: (713) 665-3818
Cell: (281) 433-2474
> On Jun 21, 2014, at 12:42 AM, David <dlocklea...@gmail.com> wrote:
>
> In the news today, it was announced that the chemist credited with the
> discovery of Kevlar,
> has passed away. Stephanie Kwolek was her name.
>
> Sometime around 1986 or 87, I was taking a materials science course at
> A&M and had access to a tensile-test machine. I asked the professor
> if I could test a piece of 5mm Kevlar cord.
>
> I put a figure 8 knot in each end. and tied each end to the steel bar
> connectors. I think I had about 15 inches between the knots.
>
> It broke in the middle of the upper knot at around 10,000 pounds.
> The professor was
> quite surprised.
>
> I used the cord in my Mitchell System, from my foot to an upper Jumar,
> several times over a 2 year period, on some pits that were under 200
> feet. At the foot attachment, I tied the Kevlar cord into a
> chicken-loop rig, described by James Jasek ( I think ) in a Texas
> Caver in the late 70's or early 80's. So that the Kevlar cord was
> the only thing holding my foot to the Jumar. I did not tie the cord
> to the Jumar eye-hole, but wrapped it around the handle and tied it
> off.
>
> While I would not recommend doing that now, I would say the cord is
> light enough to throw in the cave-pack for an emergency or as a
> back-up.
>
> David Locklear
>
> ---------------------------------------------------------------------
> Visit our website: http://texascavers.com
> To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com
> For additional commands, e-mail: texascavers-h...@texascavers.com
>
>
--- End Message ---
--- Begin Message ---
When commercially available kevlar first appeared on the scene, small
kevlar cords were put into use on sport parachutes. Before even 100 uses,
some jumpers experienced line-breaks. It was a surprise, as the very thin
kevlar lines were supposed to be over twice the strength of the polyester
lines they replaced.
In the end, I believe the failure was attributed to dirt getting into the
uncoated kevlar cord and setting up deterioration due to abrasion process
at a scale too small to visually observe.
On Sat, Jun 21, 2014 at 11:22 AM, Kevin McGowan <ke...@kevinmcgowan.com>
wrote:
> I use Kevlar for the foot loop on my frog system for years. I worked
> great.
>
> KM
>
> Sent from mobile device
> Kevin McGowan Photography
> 5250 Gulfton, Suite 2F
> Houston TX 77081
> Studio: (713) 665-3818
> Cell: (281) 433-2474
>
>
> > On Jun 21, 2014, at 12:42 AM, David <dlocklea...@gmail.com> wrote:
> >
> > In the news today, it was announced that the chemist credited with the
> > discovery of Kevlar,
> > has passed away. Stephanie Kwolek was her name.
> >
> > Sometime around 1986 or 87, I was taking a materials science course at
> > A&M and had access to a tensile-test machine. I asked the professor
> > if I could test a piece of 5mm Kevlar cord.
> >
> > I put a figure 8 knot in each end. and tied each end to the steel bar
> > connectors. I think I had about 15 inches between the knots.
> >
> > It broke in the middle of the upper knot at around 10,000 pounds.
> > The professor was
> > quite surprised.
> >
> > I used the cord in my Mitchell System, from my foot to an upper Jumar,
> > several times over a 2 year period, on some pits that were under 200
> > feet. At the foot attachment, I tied the Kevlar cord into a
> > chicken-loop rig, described by James Jasek ( I think ) in a Texas
> > Caver in the late 70's or early 80's. So that the Kevlar cord was
> > the only thing holding my foot to the Jumar. I did not tie the cord
> > to the Jumar eye-hole, but wrapped it around the handle and tied it
> > off.
> >
> > While I would not recommend doing that now, I would say the cord is
> > light enough to throw in the cave-pack for an emergency or as a
> > back-up.
> >
> > David Locklear
> >
> > ---------------------------------------------------------------------
> > Visit our website: http://texascavers.com
> > To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com
> > For additional commands, e-mail: texascavers-h...@texascavers.com
> >
> >
>
> ---------------------------------------------------------------------
> Visit our website: http://texascavers.com
> To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com
> For additional commands, e-mail: texascavers-h...@texascavers.com
>
>
--- End Message ---
--- Begin Message ---
It is well known that Kevlar is very strong but has quite low
abrasion resistance. That's why it doesn't make good caving rope. It
also has such low stretch that it can be dangerous if you take even
a short fall on it. Some stretch is desirable because it absorbs
part of the shock load of falling. Kevlar is good for foot loops and
rigging slings (runners) under certain circumstances, but it is
hardly the be all and end all of cordage.
Mark
On Sun, June 22, 2014 12:15 pm, Don Cooper wrote:
> When commercially available kevlar first appeared on the scene, small
> kevlar cords were put into use on sport parachutes. Before even 100
>uses, some jumpers experienced line-breaks. It was a surprise, as the
>very thin kevlar lines were supposed to be over twice the strength of
the >polyester lines they replaced. In the end, I believe the failure
was >attributed to dirt getting into the uncoated kevlar cord and
setting up >deterioration due to abrasion process at a scale too small
to visually >observe.
--- End Message ---
--- Begin Message ---
A few days I was talk with Efrain Mercado the president of FEALC, about the
kevlar.
He share with me this video about How to break nylon dyneema slings. Is
not the same, but is interesting to know.
http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/
Moni Ponce
(Mexico)
LCC. MÓNICA GRISSEL PONCE GONZÁLEZ
Coordinadora de la Comisión Internacional de Técnicas y Materiales de la UIS
Instructor Nacional Certificado de Espeleología por la FMAS
Directora de MP- Mex Caving
Asociación Coahuilense de Espeleología, A.C. (Fundadora)
Asociación Italiana Geográfica La Venta (Socia)
Centro de Estudios Kársticos La Venta (Socia)
Grupo Espeleológico Vaxakmen, A.C. (Socia)
Grupo Espeleológico EspeleoZots en Chetumal (Asesora)
Grupo Pionero de Espeleología en Sonora (Asesora)
Association for Mexican Cave Studies (Colaboradora)
Texas Speleological Association (Socia)
Unión Mexicana de Agrupaciones Espeleológicas (Socia)
2014-06-21 0:42 GMT-05:00 David <dlocklea...@gmail.com>:
> In the news today, it was announced that the chemist credited with the
> discovery of Kevlar,
> has passed away. Stephanie Kwolek was her name.
>
> Sometime around 1986 or 87, I was taking a materials science course at
> A&M and had access to a tensile-test machine. I asked the professor
> if I could test a piece of 5mm Kevlar cord.
>
> I put a figure 8 knot in each end. and tied each end to the steel bar
> connectors. I think I had about 15 inches between the knots.
>
> It broke in the middle of the upper knot at around 10,000 pounds.
> The professor was
> quite surprised.
>
> I used the cord in my Mitchell System, from my foot to an upper Jumar,
> several times over a 2 year period, on some pits that were under 200
> feet. At the foot attachment, I tied the Kevlar cord into a
> chicken-loop rig, described by James Jasek ( I think ) in a Texas
> Caver in the late 70's or early 80's. So that the Kevlar cord was
> the only thing holding my foot to the Jumar. I did not tie the cord
> to the Jumar eye-hole, but wrapped it around the handle and tied it
> off.
>
> While I would not recommend doing that now, I would say the cord is
> light enough to throw in the cave-pack for an emergency or as a
> back-up.
>
> David Locklear
>
> ---------------------------------------------------------------------
> Visit our website: http://texascavers.com
> To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com
> For additional commands, e-mail: texascavers-h...@texascavers.com
>
>
--- End Message ---
--- Begin Message ---
Can someone from San Antonio or Austin get this person signed up in the
Bexar or UT Grotto quick? Then the TSA, NSS, TCMA and so on...
Bill
-------- Original Message --------
Subject: Question..
Date: Sat, 21 Jun 2014 13:49:26 -0500
From: lia politi <lia.polit...@gmail.com>
To: ca...@caver.net <ca...@caver.net>
Hello,
I am an aspiring avid spelunker with experience but I have a very hard time
finding explorable caves in the San Antonio and Austin area. What is the
process like for joining your organization and is it feasible to be able to
explore caves in this area?
Thanks,
Lia Politi
--- End Message ---
--- Begin Message ---
Thanks,
I sent them a nice email inviting them to the meeting on Monday.
Geary
From: Bill Bentley [mailto:ca...@caver.net]
Sent: Saturday, June 21, 2014 2:34 PM
To: Cave Texas
Subject: [Texascavers] Fwd: Question..
Can someone from San Antonio or Austin get this person signed up in the Bexar
or UT Grotto quick? Then the TSA, NSS, TCMA and so on...
Bill
-------- Original Message --------
Subject:
Question..
Date:
Sat, 21 Jun 2014 13:49:26 -0500
From:
lia politi <lia.polit...@gmail.com><mailto:lia.polit...@gmail.com>
To:
ca...@caver.net<mailto:ca...@caver.net>
<ca...@caver.net><mailto:ca...@caver.net>
Hello,
I am an aspiring avid spelunker with experience but I have a very hard time
finding explorable caves in the San Antonio and Austin area. What is the
process like for joining your organization and is it feasible to be able to
explore caves in this area?
Thanks,
Lia Politi
--- End Message ---
--- Begin Message ---
If you are connected to numerous caving pages, it can be challenging to
keep up with the latest post.
I just started using BlinkFeed today on my new phone, and it seems to be
worth taking a look at.
The smartphone screen is filled with about 4 to 6 tiles that represent the
latest post on each site you are connected to. Scroll down until you find
a post of interest, and click on it.
For example, several Karst-O-Rama announcements were there, along with
other exciting news like yesterday's SpaceX launch.
Now if I could just get it to weed out anything with words like:
Kardashian, Bieber, Obama, Hillary, Romney, "World Cup," "global warming,"
Iraq, Iran, Cheney, Chelsea, Putin, Lewinsky, "Tiger Woods," etc, then it
would be a usable app. So instead, I just removed all my news apps.
--- End Message ---
--- Begin Message ---
http://video.nationalgeographic.com/video/magazine/ngm-china-caves-3d
Lee
--- End Message ---
