Destructive testing of aerial fabrics
on The Machine That Breaks Things
Phil Servita
aerialist at frobmob dot org
May 2007 - ???
Last updated: 14 july 2007
Synopsis:
Various fabrics used for aerial apparatus are
pitted against The Machine That Breaks Things.
The Machine That Breaks Things always wins, of course.
Results are reported. Clicking on small images will get
you larger images. All force units are lbf.
Fabric #1:
The first fabric tested was used on a weekly basis by an group of people who
have a weekly practice in the Boston area. In addition, this fabric was
occasionally used for performances. In specific, it was a 105 inch wide
12 yard long bolt of 40 denier tricot, composition 100%
polyester nylon. A small sample produced clean white smoke
when burned and left behind a clearly yellowish bead.
To determine the weave construction of the fabric, pictures of the front
and back were taken with a microscope. Front
of Fabric. Back of Fabric. It is
made with spun yarn, with the yarn appearing to be made of about 15 individual
fibers. Stare at these pictures for a while, and you can determine the
weave structure. It is, in fact, a
Single Guide Bar Tricot Weave. The diagram comes from page 12 of the
_Journal of Textile and Apparel Technology and Management_, Vol 4, Issue 4, Summer 2005.
This fabric was purchased in April, 2005, from Fabric Depot, a company
in Garwood, Texas. The actual catalog number was FT300FU. Many aerialists
procure their fabric from this source. The fabric was used until October
2006, when it was retired. At the time it was taken out of service, there were
no signs of any defects, other than smelling like a high school gym locker
room. The fabric has been kept in a dark cool place since that time, waiting
for its ultimate demise. Three separate sections from this fabric were
tested.
Fabric #2:
The second fabric tested was provided by Laura Witwer. This fabric
had been purchased from Unicycle Voltige
in 2000.
age of fabric/usage: 7 years old, used in around 25 shows and literally
hundreds of class hours over two years (guestimated 500 hours of class time).
Material composition and weave type were unknown when the fabric was shipped
to me. Fabric was retired because it was showing significant signs of wear
(scalloping around the edges, less stretch, etc.)
Burn Test.
A sample of the fabric was ignited. While in the ignition source, it
burned with a black smoke and smelled somewhat acrid and sweet. It dropped
melted drops which hardened into
a black residue. When removed from the ignition source, the sample would
self-extinguish in a short time period.
Under the microscope there seemed to be only one type of fiber. Microscope photo of fabric. The yarn is a spun
type and is made of approximately 20 individual fibers.
Composition of this fabric is almost certainly 100% polyester.
Only a single side photo is needed to determine weave type here, this one
is a very simple Single Weft Knit.
The author would like to test many more samples of fabric than he has on hand.
Fabric donations will be accepted. If you have any fabric samples you are
willing to sacrifice to the cause, please contact the author at the address at
the top of this document. New or used; it's all useful. A 3 yard section is
sufficient for the above test. a 4-5 yard section would allow a
double-sided test.
The reader is STRONGLY CAUTIONED that the results reported here say *nothing*
about the results that might be obtained with different fabric constructions,
different fabric compositions, different rigging techniques, different
suppliers, different manufacturers, etc.
They might not even say anything about the
next sections I test *from the same sample pieces*. It's unlikely, but these
results *could* just be a fluke.
Happy Flying.