Electrified Fladry for the Deterrence of Wolves

ELECTRIFIED FLADRY for
DETERRENCE OF GRAY WOLVES (Canis Lupus)
An Evolving Manual of Best Practices
By
Steve Primm, Bryce Andrews, and Amy Robinson
© People and Carnivores 2018
Table of Contents
Introduction ............................................................................................................................................................ 1
Background ............................................................................................................................................................. 1
How to Install Fladry ........................................................................................................................................... 2
A. Spooling fladry ..........................................................................................................................2
B. Carrying and driving posts..........................................................................................................4
C. Attaching fladry to the posts ......................................................................................................4
D. Anchor posts for applying tension or making corners .................................................................5
E. Maintaining consistent line height over rough terrain .................................................................7
F. Fladry gates ...............................................................................................................................8
G. Electrifying ................................................................................................................................9
Livestock Containment .................................................................................................................................... 11
Literature Cited................................................................................................................................................... 12
APPENDIX A – Installation Summary (with Index) ............................................................................. 13
APPENDIX B – List of Tools and Equipment Needed ........................................................................... 15
APPENDIX C: Fladry Spooler Specifications ........................................................................................... 17
Parts: ...........................................................................................................................................22
Introduction
This manual is for anyone installing fladry or considering its use as a proactive carnivore
conflict prevention tool. The original manual was written by Steve Primm and Bryce
Andrews of People and Carnivores, a nonprofit dedicated to preventing human-carnivore
conflicts, and Amy Robinson of the Sun Ranch Institute. Through a decade of deploying
fladry, including stretches more than four miles in length, we have garnered many
important lessons. We are certain that other fladry practitioners have made similar
discoveries and have developed useful techniques. In the following pages, we have done
our best to give a concise summary of the possibilities, challenges, and best practices
associated with using fladry in the field.
Background
There are many tools for reducing wolf predation on livestock (Shivik 2004). Among these,
fladry shows great promise in excluding wolves from pastures. Anecdotal evidence from
field trials shows that fladry may be an ineffective deterrent for grizzly bears, mountain
lions, and other species. As such, this manual refers to fladry as a tool for wolf deterrence
since it has been tested and used for years for this purpose.
Fladry consists of a line of cordage from which flags are suspended. Field experiments
demonstrate that properly deployed fladry can be effective for as long as 60 days (Musiani
et al. 2003). Electrified fladry—fladry combined with sufficient electrical current—is even
more effective when properly deployed. Research indicates that electrified fladry (aka
“turbo fladry”) has a longer duration of effectiveness (Lance 2009).
While electrified fladry has the potential to be highly effective in excluding wolves from
pastures, adoption of this tool remains limited. There are several reasons for this: high
capital costs (approximately $2,600 per mile for fladry, excluding labor, $600 for energizer
with battery, and $400 for posts); limited availability of fladry; and skepticism about
effectiveness.
Fladry can also be difficult to deploy without proper equipment and training. Because the
flags create voltage leaks when they touch other objects, a powerful fence charger is
required to keep sufficient voltage flowing through electrified fladry. Topography and
other particulars of the site must also be considered, as the flags can become tangled in
vegetation and fences making them ineffective deterrents.
Despite the tool’s steep learning curve, fladry can be an effective and efficient strategy for
proactively addressing potential wolf conflicts. Significant strides have been made in the
past decade in the application, installation, and breakdown of fladry systems. When fladry
was a relatively new technology, deployment was extremely labor intensive. Lance (2009)
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documented labor inputs of roughly 32 person-hours per kilometer of fladry, or
approximately 50 person-hours per mile. As a mile of fladry is required to surround a 40acre pasture—a size typically used for calving—the labor cost has historically driven
ranchers to abandon the tool. Today, however, fladry can be deployed at a rate of 7 personhours per mile with appropriate technology and a trained crew and can be uninstalled even
faster.
Once fladry has been erected, it is essential to keep it effectively deployed. Wind,
precipitation, and ungulates can cause fladry to sag, collapse, or become dismantled. While
there are many similarities between a conventional polywire fence and electrified fladry,
the weight and wind resistance of the flags themselves add a new dimension. If fladry is to
be effective, it must be checked and maintained regularly. Such maintenance—which
typically amounts to 1 person-hour per week for a fladry fence in good condition—can be
integrated into the daily ranching routine.
A fladry enclosure often follows the contours of an existing pasture. For user convenience,
the fladry line must duplicate every gate in an existing permanent pasture fence. Where the
electrified fladry line crosses existing fence lines, care must be taken to keep the wires
properly insulated to avoid voltage shorts.
While there are challenges to using fladry, there are many anecdotal accounts of its
successful use, as well as strong evidence gathered from field trials. We have utilized fladry
on many projects with no losses, and have found the tool particularly well suited for use in
calving pastures or other small, high-risk grazing units.
How to Install Fladry
In this section, we provide
instruction and photos related
to the deployment and
maintenance of fladry. As we
mentioned in the introduction,
fladry’s effectiveness depends
on efficient and proper
installation.
A. Spooling fladry
After multiple deployments,
we have taken a hard look at
what makes fladry
Figure 1: Hand coiling fladry is extremely inefficient.
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deployment so potentially inefficient. With numerous experienced workers, we repeatedly
found the biggest time sink was in dealing with hand-coiled fladry. Even when neatly
coiled, it is unwieldy and prone
to tangling. Also, ¼ mile coil of
fladry (1320 feet) is fairly long,
somewhat heavy, and a handful
even for people with large
hands. Thus, workers
inevitably set the coils down or
try to hang them on fences
when carrying them in the field
—another opportunity for
tangling.
Most professional graziers
insist on using spools or reels
for handling temporary electric
Figure 2: Fladry spooler 2.0 in action.
fence wire in the pasture
because tangles waste time and make fence construction unpredictable and inefficient.
Adding flags to the polywire makes the tangling problem exponentially worse. Thus, we
cannot stress enough that fladry needs to be spooled up. Fladry on a spool has greatly
improved our efficiency, as well as making fladry easier to store.
Other users have noted the potential efficiency gains of spooling fladry, and have developed
their own methods and equipment. Our fladry spooler is a simple machine with minimal
moving parts, and can be constructed
from readily available parts with no
custom machining required. Complete
details and a parts list are available in
Appendix A. Our larger spools will hold
more than 1½ miles of fladry,
depending on how tightly it is wound
up. We have found that 1½ miles of
fladry makes a very heavy spool, so we
generally limit our quantities to
between ½ and 1 mile per spool.
Figure 3: 1.5 miles of fladry on one spool.
Because of the bulk of the flags, fladry
requires a far larger spool than does
bare polywire. Therefore, when
considering a spooling device, think
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big: 6 inch minimum bare spool diameter and 11 inch minimum spool width. While there
are many excellent electric fence reels available, these are generally too small to hold more
than a trivial amount of fladry.
B. Carrying and driving posts
As with any temporary electric fence, fladry needs to be
attached to something to keep it at the correct height. The
most popular and economical choice is 3/8 inch x 4-foot
fiberglass rod posts. Handling dozens of these posts in the
field, while also wielding a hammer to drive them in the
ground, can be challenging. One unique solution was
suggested to us by a professional grazier in Wyoming: use an
old golf bag. The fiberglass posts slide into the golf club slots.
Workers can sling the bag across their torso, allowing them to
carry roughly 40-50 posts hands-free. Having both hands free
allows the worker to pull a post from the bag with one hand,
position it, and then tap it into place with a hammer in the
other hand. This dramatically shortens deployment time over
carrying the posts in one’s hands.
Figure 4: Golf bag filled with fladry posts; bag
pockets can be used to store small parts.
C. Attaching fladry to the posts
Fiberglass posts—spaced roughly 32 inches
apart, or substantially closer than for bare
polywire—need some sort of attachment
point for joining fladry to post. After much
trial and error, we have found one product
to be far superior: Premier Fence’s Harp
Clip. The Harp Clip is durable, stays where
you want it, and allows the fladry flags to
slide through rather than snagging when
tightening up the line. Clips made of wire
springs snag the flags. Clips that look similar
to the Premier Harp Clip have not performed
well and tended to come off the posts.
Figure 5: Using a golf bag for posts leaves hands free for
positioning and hammering posts.
The Harp Clip is also well-suited to the golf
bag technique because the clips can be left on
the posts with no risk of entangling with each
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other. This makes storage of large quantities of
posts easier as well. The only difficulty with the
Harp Clips is that they can be difficult to install
since they are made of very strong plastic.
Premier Fence has responded by making an
inexpensive tool for snapping the clips onto the
post.
D. Anchor posts for applying tension or
making corners
The 3/8-inch fiberglass posts are the mainstay of a
fladry line; however, they are also very flexible
and smooth. Thus, when trying to add tension to a
Figure 6: Premier Fence Harp Clip.
segment of fladry so the line does not sag, we cannot rely on the 3/8-inch posts by
themselves.
These smaller posts will bend and will eventually pull out of the ground as we add tension
to the fladry. Therefore, it is necessary to install heavier posts at regular intervals for
adding tension to the line. We experimented with numerous ways of doing this and with
different spacings and found that, on rolling terrain, it was necessary to have a heavier,
less-flexible post approximately every 250 feet.
Figure 7: Steel T-post as an anchor for tensioning the fladry line in a fladry +
polywire setup for dividing a cattle pasture. Note plastic insulators on post.
Steel T-posts are one option for
heavy anchoring posts, as they
are durable and reliable. They
have drawbacks, however; they
weigh a lot and require a postpounding device to install, as
well as a device for removing
them from the ground at the end
of the deployment. In addition,
since they are steel, they require
careful attention to insulation
because if the electrified fladry
line contacts the steel, it creates
a “dead short,” or a complete
loss of voltage.
While we still use T-posts in
some situations, we have found
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better alternatives for
tension anchors. In
situations where the fladry
line parallels a permanent
fence, we found that we
could periodically tie the
fladry line to the
permanent posts using
plastic insulator clips and
twine. These anchors
proved to be reliable, and
the hardware was far more
portable than steel T-posts
and a pounder.
Our preferred method
involves Dare-brand
corner insulator clips and
a length of twine, with fence staples connecting to a wooden post. The Dare clip (Part #
BW-CP-10) proved to be very durable and very affordable at less than 10 cents each.
Figure 8: Tensioning anchor, using a Dare-brand insulated clip and twine to connect
the fladry line to a permanent post.
We have also begun using a variety of thicker/stronger fiberglass and composite posts for
these purposes. Unlike steel T-posts, these posts require no insulators as they do not
conduct electricity. Composite posts like the Powerflex G2 and PasturePro have performed
the best—they are fairly flexible,
nearly indestructible, and have
enough roughness on their surface
to help them stay in the ground.
Smooth fiberglass posts may pull
out of the ground under strain
(however, this makes them easier
to remove).
Composite posts range up to 2 3/8
inches in diameter and are
comparable in price to steel posts.
Half-inch diameter fiberglass posts
are substantially stronger and
Figure 9: Powerflex composite post used to provide mid-line tension for
fladry. Wire clip inserted through post keeps fladry at proper height;
multiple half-hitches around the post vary the tension on the line.
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stiffer than 3/8-inch diameter and can be used to
make a fladry segment more robust in
challenging conditions.
For creating a 90-degree corner in a fladry line,
however, it is still hard to beat a steel T-post.
Again, it is imperative that the electrified fladry
line not make any contact with the post. We have
found that the Dare clip anchored to a T-post
makes a strong, reliable, insulated connection.
There are other insulators for T-posts, but we
have found it preferable to have some space
between the line and the steel.
E. Maintaining consistent line height over
rough terrain
Figure 10: Galvanized clip for half-inch fladry posts; this
clip is very strong.
Fladry flags should be kept slightly above the ground when possible to minimize voltage
leaks from the flags. The line must not, however, be raised higher than about 28 to 30
inches. A line higher than roughly 29 inches may allow wolves to walk under the line
without getting shocked.
On many pastures, the fladry line will have to contour over rough terrain, crossing ditches,
ravines, and other features. Keeping the fladry line at a fairly consistent height in such
places can be challenging. It is possible to use posts to keep the line at the desired height,
but in extremely rough terrain the tension on the line may be enough to uproot most any
posts besides T-posts. Compounding matters, many ravines and draws are extremely rocky,
making it difficult to manually drive Tposts or composite posts into the ground.
The Dare corner insulator clip once again
proved very useful in such situations.
Using the Dare clip, a length of nylon cord
(such as parachute cord), and a goodsized rock, we improvised a “deadman”
for holding the line parallel to the terrain.
Again, this has the advantage of being
highly portable and with no risk of shorts
relative to steel posts.
Figure 11: Dare clip deadman.
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F. Fladry gates
A necessary part of any fladry
deployment, gates are fairly simple to
construct; they just require a pair of
fixed anchor posts, as described above,
so that adequate tension can be
maintained across the gate. It is
possible for one end of the gate to be
anchored to a permanent fence post
near the gate, but it is inadvisable to
put the gate or any other segment of
the electrified fladry line within fladryflag’s length of the permanent fence
due to flag entanglement or electrical
short risk.
Figure 12: Fladry gate parallel to permanent gate. Both gates open
The gateway should be wider than the from the right.
permanent gate it parallels (Figure 12).
This will allow plenty of room for moving vehicles and livestock through the gate. The free
end of the fladry gate should be on the same end as the permanent gate to facilitate easy
use.
Electric fence gate handles are
required hardware for gate
construction. Good quality
handles cost about $4.00 and are
far superior to the $2.00 varieties.
Figure 13: Gate handle connected to eye-bolt, attached to a Powerflex
composite post.
Cut the fladry line where a gate is
required and tie the end to the
eye on the end of the gate handle.
To ensure a good electrical
connection, wrap the polywire
two or three turns around the
gate handle eye, then tie it off
with a bowline or other suitable
knot. The gate handle’s hook end
(the free end) will then need to
be connected to an anchor post
that can withstand tension.
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We suggest a minimum of 7/8 inch
diameter fiberglass or composite post
such as the Powerflex 1.6-inch composite
post, with a hole drilled through to accept
an eye bolt (Figure 13). The gate handle’s
hook end then clips into the eye bolt. The
fladry line continuing from the gate can
then be tied into the eye bolt; again, make
multiple turns around the metal to ensure
good conductivity.
A gate connector, called a wood-post
activator, is another good solution. This
can be screwed into a permanent wood
post. If using this method, the fladry gate
must not be closely parallel to the
Figure 14: Gate handle connected to a wood post activator/insulator.
permanent gate, but should intersect the
fixed post at an angle that keeps most of the fladry line a good distance from the permanent
fence. Otherwise, the flags will tangle in the permanent fence and/or the electrified fladry
will short on the permanent fence, rendering it ineffective.
T-posts also work for gates, but require reliable insulation. We have used several
insulator/connector devices that worked well on T-posts. It is also possible to use insulated
fence wire wrapped around the T-post as a makeshift device for connecting gates.
G. Electrifying
Once the various posts and gateways have been installed, and the electrified fladry line has
been attached to the posts and adequately tensioned to prevent sagging, it is time to add
the electricity itself. This is fairly straightforward, and any good fence energizer will
include an illustrated manual for proper installation.
It is important to select a good quality fence energizer for electrifying fladry. The flags
themselves create significant voltage leaks, especially if they are in contact with vegetation
or the ground. Thus, electrified fladry requires a significantly stronger energizer than an
equivalent length of bare polywire.
The baseline strength of electric fence energizers is measured in joules. Some
manufacturers report stored joules, while others report output or released joules. The most
important number to focus on is output joules as a parameter of the energizer’s ability to
supply voltage over a wide range of situations.
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Based on our monitoring of fladry voltages in a variety of settings, we believe that a good
general guideline is that an energizer should have at least one (1) joule of output per
mile of fladry. We found that an energizer with 3-output joules (Horizont Hotshock A50)
with a fully charged 12-volt battery delivered consistent voltages of 4 to 5 kilovolts on
more than 3 miles of electrified fladry. This was under challenging conditions, with the
fladry in contact with tall sagebrush and other vegetation.
In addition to the guideline of 1 output joule/mile of fladry, we also recommend adding
more ground rods to the energizer than the manufacturer specifies. In the case of the
Hotshock A50, Horizont recommends 6 feet of ground rod; we used 3 ground rods, 3 feet
each, for a total of 9 feet. High-quality rods are made of either copper or galvanized steel.
The Horizont Hotshock A50, as well as a few other energizers from Horizont and other
manufacturers (available through Premier Fence, e.g.), are termed “wide impedance”
energizers. Wide impedance energizers may not have as high a peak voltage as other
energizers, but they deliver far better average voltage under adverse conditions. Such
conditions are fairly common in the Intermountain West when dealing with wolves:
1. Dry, high mineral content soils that do not conduct electricity well.
2. Dry snow in cold temperatures serving as insulation from electrical shock.
3. Long fur insulating the animal against electric shock (particularly an issue in winter
with wolves, especially when they may be standing on dry snow).
Since these factors are fairly
routine when dealing with
wolves, we suggest that fladry
practitioners seriously consider
using only wide impedance
energizers.
Other points to keep in mind
regarding electricity:
Figure 15: Horizont wide-impedance energizers with solar panels. The
Hotshock B4 (left), with 0.35 output joules, is a compact unit that is suited for
smaller runs of fladry around corrals or small pastures. The Hotshock A50
(right) is a heavy-duty unit that can adequately power more than 3 miles of
electrified fladry; its 40-watt solar panel ensures a well-charged battery.
During spring and summer
growing seasons, it may be
impossible to keep the flags from
touching vegetation because the
grass is growing so fast. Line
height should be adjusted as
necessary.
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When surrounding pastures with permanent fences, the fladry line is likely to cross over or
through existing fence lines. Each of these is a potential short that must be insulated. Short
runs of insulating tube can be made from rubber garden hose (the black heavy-duty hose),
which can be slit lengthwise then taped on with electrical tape.
A good voltmeter is absolutely imperative for monitoring energizer performance and
locating problems. Accurate voltmeters are available for less than $50; more sophisticated
models that help find shorts are roughly $120.
Livestock Containment
Thus far we have focused on fladry as a wolf deterrent. Clearly, in circumstances where
there is no permanent fence containing the livestock, ranchers and practitioners need to
rely on the fladry fencing for this purpose.
We have found that standard electrified fladry was only marginally effective as a livestock
fence. This was because flag lengths of 19 inches dictated a top wire height of no greater
than 23 inches above grade (Davidson-Nelson and Gehring 2010). In our projects, we found
that cattle would often step over a fence that low, which frequently led to brief
entanglements that resulted in long stretches of fladry being torn down and rendered
ineffective.
We experimented with longer flags that would allow the top electrified wire to be closer to
the recommended cattle containment height of 30 to 32 inches. After discussion with
experts and extensive research, we could find no compelling rationale for flags only 19
inches long. We think, however, that there is an upper limit on effective height for fladry:
too high, and wolves would find it too easy to cross under the electrified wire without ever
making contact.
Therefore, we believe that the optimal top wire height should correspond to wolf
anatomical parameters—the wire height should be slightly below average shoulder height
for a wolf, or about 29 to 30 inches. We base this on the idea that wolves that begin to lose
their fear of fladry will first explore the novel object with their nose and mouth. Canids
with a curious attitude often hold their head slightly below shoulder height as they explore
novel objects.
Therefore, we believe 27 inches is the theoretical optimum flag length; this would allow
deployment of the top wire at approximately 29 to 30 inches above grade without the flags
making excessive ground contact (a significant voltage drain). Preliminary trials with cattle
have shown that 29 inches is an effective wire height for containing adult cattle.
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Literature Cited
Davidson-Nelson SJ and Gehring TM. 2010. Testing fladry as a non-lethal management tool
for wolves and coyotes in Michigan. Human-Wildlife Interactions 4(1):87-94.
Lance NJ. 2009. Application of electrified fladry to decrease risk of livestock depredation by
wolves (Canis lupus). MS Thesis, Utah State University, Logan.
Lance NJ, Breck SW, Sime C, Callahan P, Shivik JA. 2010. Biological, technical, and social
aspects of applying electrified fladry for livestock protection from wolves. Wildlife Research
37:708-14.
Musiani M, Mamo C, Boitani L, Callaghan C, Gates CC, Mattei L, Visalberghi E, Breck S, Volpi
G. 2003. Wolf depredation trends and the use of fladry barriers to protect livestock in
western North America. Conservation Biology 17(6):1538-1547.
Shivik JA. 2006. Tools for the Edge: What’s new for conserving carnivores. BioScience
56(3):253-59.
Shivik JA. 2004. Non-lethal alternatives for predation management. Sheep & Goat Research
Journal 19:64-71.
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APPENDIX A – Installation Summary (with Index)
To install fladry:
Spooler – Spool .5 to 1 mile of fladry on a spool so that it’s not too heavy (larger spools can
take 1.5 miles of fladry, but they are heavy). The spooler itself must be larger than what can
be used with bare polywire. pp 3-5, and Appendix C (for spooler assembly)
Posts and carrying/driving posts – Use an old golf bag or other carrying bag that allows the
worker to carry 40 to 50 fiberglass posts (3/8 inch x 4 feet) and be hands-free (to position
posts and tap into place). p 5.
Anchor posts for tension and corners – The 3/8-inch fiberglass posts can pull out with
tension, so we suggest adding heavier, less flexible posts approximately every 250 feet.
Options include composite posts such as Pasture Pro’s 1.5” x 5’ line post, steel T-posts,
stronger/thicker fiberglass posts, or tying the fladry to permanent fence/posts with nonconductive cord. pp 6-8.
Tension – It is best to stretch the fladry in segments of less than 1/4 mile, and to apply
tension before clipping it to the posts. Pull hard to remove all slack from the line, then
secure the fladry to the nearest heavy post or corner. pp 5-7.
Attaching fladry to posts – Fladry line needs to be clipped to the fiberglass posts (3/8 inch x
4 feet), which should be spaced roughly 32” apart (closer than for bare polywire). The best
product for attaching fladry to a post is Premier Fence’s Harp Clip. We also recommend
using Premier’s inexpensive tool for snapping the clips onto the posts. pp 5-6.
Adjusting and maintaining line height – The fladry line will need to contour over the
terrain. Walk the line to ensure consistent height. Fladry flags must be kept from leaking
voltage by touching the ground, vegetation, etc., and the line height must remain effective
(23-30”, depending on the length of your fladry, with flags hanging approximately 1-2”
from the ground. We recommend 27” flags with a line height of 28-30”). Add extra posts
where necessary, and consider using the Dare corner insulator clip to improvise a deadman
to hold the line parallel to the terrain. pp 8-9.
Fladry gates – A necessary part of the installation, gates require a pair of fixed anchor posts.
The gate should be wider than any permanent gate it may parallel. One end of the fladry
gate can be anchored to a permanent fence. Also needed are a handle and gate connector.
pp 9-10.
Electrifying – Select a high quality, strong fence energizer, as fladry flags generate voltage
leaks. The most important number is output joules. We recommend at least one (1) joule of
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output per fladry mile. We also recommend adding more grounding rods to the energizer
than manufacturer specs dictate. Copper or galvanized steel rods work well. pp 10-12.
Livestock containment – The line needs to be near the ideal cattle containment height of
30-32” but also correspond to the height of wolf heads and noses (the likely way they might
explore the fence), about 30”. We recommend a fladry flag length of about 27”, with the top
line height at 29-30”. p 12.
Testing – Use a voltmeter to measure the voltage of the fence. 4,000-5,000 volts is an
acceptable reading, but higher readings (up to 10,000 volts) are preferable. p 11.
Communication – Talk with the landowner and any immediate neighbors to let them
know that you have installed an electric fence. Consider hanging a plastic warning sign
on or near the fladry line to avoid accidents.
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APPENDIX B – List of Tools and Equipment Needed
•
Sufficient fladry to enclose the pasture
•
Fence energizer capable of delivering one output joule per mile of fladry
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Line, corner, and tensioning posts
Ground rods for energizer and lightning brake
Insulated wire to connect charger to fence
Uninsulated wire or braided aircraft cable to connect charger to ground field
Lightning diverter or brake
Fladry spooler
Deadblow hammer or cap for driving fiberglass line posts
Pounder for T-Posts and larger-diameter composite posts
Sledgehammer for driving ground rods
Utility knife for cutting and splicing wire
Split bolts for electrical connections
Nonconductive cord
Spare harp clips
Corner clips
Pinlock plastic insulators
Cotter pins for composite posts
Drill and drillbits
Screws
Fence staples
End strain insulators
Dead end gate handles
Pass through (conductive) gate handles
Voltmeter/fault finder
Leather or rubber-palmed gloves for handling fiberglass posts
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APPENDIX C: Fladry Spooler Specifications
Figure A: Spooler 2.0, which included a level-winding device to evenly distribute the fladry on the spool.
The level winder has been omitted from subsequent designs.
Our fladry spooler has gone through a few iterations, finally evolving into a simple machine that can be
constructed with minimal welding and pre-fabricated parts. The basic design is for a hand-cranked
machine that fits into the hitch receiver on a vehicle; the design can be readily modified to make the
spooler freestanding or attachable to an ATV rack. To increase the spooler’s versatility, we designed it to
use easily interchangeable spools, as well as to use a variety of different spools to suit user needs.
Our original design aim was to make the spooler collapsible into four main parts. However, as the design
grew simpler, we realize now that the spooler can be built to have just two major components: the
frame, and a detachable axle (or spindle) for holding the spool. This keeps the spooler lightweight and
with fewer parts to lose.
The spooler frame is made of steel tubing; we used 2”x2”x0.25” for the horizontal piece that inserts into
the vehicle’s hitch receiver. The angled arm piece is 2”x2”x0.188”; this lighter tubing saves weight, and
© People and Carnivores 2018 17
allows “telescopic” assembly by accommodating 1.5”x1.5” tubing if the spooler is made to be
collapsible. We set the arm at a 65° angle from horizontal.
Figure B: Spooler specifications. The frame can be built in one piece instead of two, if desired.
The next piece is the 3”x2”x0.188” rectangular tube to support the spindle and spool. This material can
be welded directly to the angled arm; or it can be welded to 1.5” square tubing if collapsibility is desired.
We made this piece 10” long.
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At 8.5”, we cut a through-hole into the 3”x2” tubing; this hole is to accommodate a pipe coupling. We
used a forged pipe coupling for durability, and selected one threaded for 1.5” nominal pipe diameter.
This size allows flexibility in choosing spools, since reducing bushings can be threaded into the coupling
to accommodate smaller diameter pipes as
spindles.
The pipe coupling can be accessed from
either side of the frame. This allows the user
to put the spindle on either side, or to run
two spools at once if necessary.
Figure C: Pipe coupling detail; coupling can be accessed from either
side of frame for versatility.
Spindles or axles can be made from
whatever shaft material the user desires.
However, we found that pre-cut, prethreaded galvanized pipe made suitable
spindles with sufficient strength, even under
demanding loads over rough terrain.
Threaded on both ends, the pipes easily
threaded into the coupling on the spooler
frame, and allowed use of a floor flange to
keep the spool on the spindle in the field.
Figure D: Top view of pipe coupling welded into 3x2 tube; note
reducing bushing on right receiving 1" pipe as spindle.
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We found that McMaster-Carr polyethylene spools were affordable, durable, and lightweight. The size
that has worked best for us was a 17” wide by 6” diameter spool core, with 24” flanges. This spool was
large enough for over a mile of fladry if wound tightly.
The diameter of the hole on the spool core is
1.5”, which is larger than the outside
diameter of 1” nominal pipe and smaller
than the outside diameter of 1.5” nominal
pipe. Thus, it may be a good idea to use a
bushing of some sort on the pipe spindle.
Bushings make the spool rotate far
smoother and easier, and also minimize
wear on the spool.
Figure E: Polyethylene spool from McMaster-Carr; note detachable
handle on flange.
We used bronze bushings
(sleeve bearings) from
McMaster-Carr. There was no
size available to precisely fit
both the spindle and the spool.
McMaster-Carr part # 6381K271
was a close fit, requiring minor
reaming to fit the bushing onto
the pipe. Users may find this
bearing may require a slight
reduction in outside diameter to
fit the spool, but the
polyethylene is flexible enough
to slide onto the bearing with no
Figure F: 1" nominal pipe spindle, with bronze bushings for smooth spool rotation.
modification in most cases.
Three bushings to accommodate different size spools.
Bushings can be fixed in place on
the spindle with a small welded
bead or adhesives.
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The spools need handles for the user to wind up fladry. McMaster-Carr has handle assemblies that work
well. We chose rotating plastic handles that can be bolted to and easily removed from the spool flanges.
This eliminates the need to have a
handle for every spool, and allows
spools to be easily stacked for
storage.
The handle has a threaded stud;
we used a coupling nut and a
wide-head bolt to attach the
handle to the spool flange. A
reinforcing spacer of metal or
plastic on the inside of the flange
is optional, but should increase
flange durability.
Figure G: Removable spool handle attached to flange.
Figure H: Handle removed from spool; note coupling nut & bolt.
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Parts:
1) Forged pipe coupling, McMaster-Carr part number 7739K148
2) Reducing bushing, McMaster-Carr part number 4638K572; also widely available at hardware
and plumbing stores.
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3) Bronze (alloy 932; cleaner than Oillite) bushings, McMaster-Carr part number 6381K271
Outside diameter: 1 5/8”
Inside diameter: 1 5/16”
Length: 2.5”
4) Floor flange; this item should be purchased at hardware or plumbing store.
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5) Tapered, rotating handle, McMaster-Carr part number 6308K46
6) Coupling nut 1.75” length, for handle; 1/2"-13 thread; McMaster-Carr part number 90977A195.
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7) Bolt 1” length, ½”-13 thread; for attaching coupling nut/handle assembly through spool flange;
McMaster Carr part number 91255A712 button head socket-cap bolt. This bolt has a low-profile
head so it doesn’t snag fladry. Uses a 5/16” Allen wrench to attach or remove the handle.
8) Components for Polyethylene spools
a. 17” spool core, McMaster-Carr part number 38305T12
b. 24” spool flanges, McMaster-Carr part number 38305T23
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