From: king@reasoning.com (Dick King)
Newsgroups: rec.sport.fencing
Subject: Re: Fencing equipment (was: Re: Fencing is here? Incredible!!)
Date: 14 Dec 92 19:26:04 GMT
Organization: Reasoning Systems, Inc., Palo Alto, CA

In article <1992Dec14.062541.27786@magnus.acs.ohio-state.edu> scasterg@magnus.acs.ohio-state.edu (Stuart M Castergine) writes:
>
>Add the care and longevity problems of Kevlar in, and it is just a
>loser unless you are a serious fencer. FIE equipment may be safer, but
>the old standard was perfectly safe, if you had well-maintained
>equipment.

I have a big problem with Kevlar.  It breaks down in the presence of water.

If you have a bullet-proof vest it needs to be replaced if you tear the plastic
covering even if it's done in a manner so as to not stress the Kevlar.  

My kevlar bicycle tires lose strength if they get little nicks and then it
rains*

Here is a message i got from an SCA member with whom i raised this point

  Replied: Fri, 22 Mar 91 16:15:57 +0000
  Replied: "tjmailer@ecn.purdue.edu (Thomas D Johnson) "
  Replied: Wed, 06 Feb 91 18:31:20 +0000
  Replied: "tjmailer@ecn.purdue.edu (Thomas D Johnson) "
  Forwarded: Wed, 06 Feb 91 11:36:16 +0000
  Forwarded: "SINISTER@AC.DAL.CA "
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  Date: Wed, 6 Feb 91 14:32:50 -0500
  From: tjmailer@ecn.purdue.edu (Thomas D Johnson)
  Message-Id: <9102061932.AA13798@bank.ecn.purdue.edu>
  To: king@reasoning.com
  Subject: Re: composite mundane fencing blades
  Newsgroups: rec.org.sca
  In-Reply-To: <9101311827.AA00899@piano.reasoning.com.res_no_yp>
  Organization: Purdue University Engineering Computer Network
  Cc: 

  About Kevlar: Kevlar, along with many high-strength glass and polymer fibers,
  weakenns dramatically if exposed to moisture contents above those they were
  manufactured under, due to chemical interaction with the water molecules on
  the fiber surface. This leads to micro-cracking and crystallization of the
  polymers, which reduces their ability to absorb impact energy, such as
  ballistic impacts.  The primary mechanism for prevention of penetration of
  bullets into bulletproof vests and similar garments is by absorbing all of
  the energy of the bullet into breaking of the high-strength fibers, although
  a fair portion ends up being transmitted to the wearer, spread out over a
  much larger area (tending to lead to severe bruises and possibly broken
  bones, but not bullet penetration wounds).  As such, the sealed packets of
  ballistic fiber (whether Kevlar, nylon, fiberglass or whatever) are replaced
  after moisture exposure or after being hit with bullets, as they have a
  severely reduced capacity for absorbing impact energy. While this may not be
  as much of a problem with fencing impacts due to the much lower energy
  content and velocities of the weapons, it is still a consideration. If you
  are looking for further information on such fibers, you may want to contact
  manufacturers such as E.I. DuPont Nemours, who are usually willing to give
  information of their products.

  Yours in the Society,
  Ld. Thomas Mailer
  Barony of Rivenstar, Middle Kingdom

  (sorry for the rather technical nature of this message, but its what I do for
  a living here at Purdue University; I am a materials engineer specializing in
  technology transfer, technical information assistance, and industrial
  troubleshooting. I am currently working on my master's degree.

   - Thomas D. Johnson)

I, myself, like the thought of Nylon, which is used to tether marine boat
anchors, rather than Kevlar.  Some of my favorite arteries and wiring are
located next to some of the worlds bigger sources of warm, salty water.  I
suspect that Kevlar FIE garments meet the standards when NEW, but i have no
reason to believe that there is a standard that says that the garment must meet
standards after having been used twice a week for two years.

-dk

* Which, admittedly, hasn't happened enough lately to make this a serious
  business