Build An Electric Bear Fence

[Kevin Dill]

DIY Electric Bear Fence - Complete Pics p 2

After many trips to the backcountry and some bad run-ins with bruins, I've come down on the side of taking an electric fence along whenever possible. My partner bought the UDAP kit but I am truthfully not at all impressed with much of the components in it. The posts especially are just shy of being useless in my mind. I have used electric fences many times around my farm and understand the mechanics very well, so I decided to build my own GOOD fence while keeping it packable and light.

I started by ordering a Speedrite AN20 energizer, 1" white equine tape (instead of wire), insulators, tape-connectors and a couple odd components. That was the easy part. Making good posts required some thought. After much debate I ended up buying a dozen cheap carbon arrow shafts and extra threaded glue-in inserts. My plan is to cut each 30" shaft into 2 x 15" pieces, and glue inserts in each end of each piece. I'll use 8-32 all-thread to make the connections. Three sections screwed together will make a 45" post to insert in the ground. I'll use a light field point for the bottom tip of the post. I'll make 6 total posts and my enclosure will be hex-shaped. I also will make paracord loops and epoxy them into the top of each post which will make for easier guy-out bracing if needed. When it's all done everything will fit in a 16" x 8" bag.

I didn't really do this to save money, though I will do exactly that. I want a sturdy fence with no hassles and it must work well. I also wanted it to be compact and as light as possible. One thing I'm still exploring is some way to make and attach a very low profile insulator suitable for the 1" tape. I've been thinking about pieces of 2"-long rubber tubing slid down over the shaft (post) to the correct height. The 1" white tape would be placed against the rubber tube and secured with a small zip-tie or some other form of easy attachment.

Your thoughts?

 

[Shrek]

I'll be interested in how it works out. The arrows are definitely strong but carbon is a good conductor so the insulators are key to making it work.

 

[dotman]

Not sure if this helps but here are some low profile insulators, I've been thinking Bout doing the same thing. I have the AN20 already and plenty of old arrows.

http://www.bestbearfence.com/products/components/insulators/insulators.htm

 

[Kevin Dill]

dotman...thanks. I've been on that site and looked at those insulators. Here's the problem:

Most insulators are made to simply support the wire or tape (hold it up) but aren't designed to endure horizontal pull away from the post. If you use them in the corners and pull the wire/tape fairly tight the 'arm' can bend open from the pressure. There are other insulators which don't do that, but most of them are rather bulky for packing. I've tried turning the insulators outward, but it seems the wire/tape will manage to touch the post somehow. I think...but don't know yet...that a piece of rubber tubing on the post/shaft would allow the tape to be place around the outside of the posts...over the rubber tubing...and be adequately protected from contact. All that remains is to lightly secure the tape to the rubber tubing so it can't ride up or down the post. That could presumably be done with electrical tape, zip-ties, or maybe some other simple and reusable attachment. The beauty of this is its simplicity and lower bulk (no plastic insulators to store). I think it will work, but it needs tested.

Soon.

 

[colonel00]

Here is the one I made:

http://www.rokslide.com/forums/showthread.php?18729-DIY-Bear-Fence

Oh, and as far as an insulator, I ended up just using electrical tape. Basically I started the tape sticky side out, went around twice then flipped it over. Essentially it is tight enough to stay on the pole but there is no stick. This way I can move it up and down to adjust heights.

 

[go4thegusto]

We bought a 2)D cell DC unit at the Farm & Fleet. I went to a golf pro shop and was given take-off carbon club shafts. We replaced the solid ground rod with 1/2 inch piece of copper plumbing. used white ribbon tape however if you can find the new dual line tape (pos and negative loomed in) then animal does not have to complete circuit to the soild which in dry ground or dry pine needles can be an issue. The whole system is light and works well. We just duct taped ribbon to shaft and tied back to trees or brush to maintain tension with parachute cord. Shafts are clear coated so heavily they won't conduct. Worked well on Kodiak and MT grizzly country.

 

[rayporter]

i just put and ohm meter on a carbon arrow and this arrow did not conduct. easy to check or get someone to check it for you.

rubber hose or rubber tube or tape must be rated to carry the voltage - it wont matter on fiber glass or the particular carbon arrow shafts i have. but it will matter on aluminum shafts. the para cord or any poly string will work great and i have used it for years for insulators on corners.

dont trust the coating on aluminum it will break down and short out. even if you use garden hose with insulated 12 ga. wire on a steel corner post it will short out. the farm stores sell special rubber tubing for the fencers rated to like 10,000 volts or whatever. garden hose shorts out instantly. stick yer finger inside and test it.

 

[Beendare]

Interesting...and good timing as i am going to either buy or make one of these.

Re construction; You can order replacement aluminum tent poles (strong, light, doesn't matter they are conductors) for the posts as there are fittings you can epoxy into the end that have a loop that will fit paracord. Maybe even rubber dip them.

interesting link that answers a lot of questions on these fences
http://www.speedrite.com/en-us/resources

So they recommend 5,000v for bears...and they recommend baiting it.

I see the speedrite unit puts out .04J, but I couldn't find the voltage rating. Does that unit have enough zing?

I'm curious as to why you decided on tape vs wire? Is there one tape better than another?

 

[Kevin Dill]

Beendare...

Post flexibility is a bad thing in these fences. Most fences are built in linear fashion and the posts simply hold the wire up...livestock situations. A bear fence is a small enclosure and the wire tries to pull the posts inward, sagging the wire. The more the posts flex, the worse things sag. I decided on .300 spine carbon shafts for their stiffness, and they will still be light enough in weight.

The Speedrite AN20 is the unit found in the UDAP rigs and is commonly used for bears. It has enough punch to dissuade a bear which is unfamiliar with electricity. Important to understand that electricity is a totally foreign and negative experience for a wild bear. It doesn't take massive energy to send the message. If their brain and CNS demands immediate withdrawal, that's what matters.

Visibility of the fence wire is important. I went with the tape because it is highly visible and any approaching bear will see it. They will almost always smell/mouth/lick it to investigate, and that moist surface is perfect for a shock. In fact, under good conductivity (animal on moist ground) they don't actually have to touch the wire/tape. I've witnessed the energy arc from the fence to a nose (dog) across 1/2" space. The instantaneous reaction to get away is what we need. I went with 1" tape simply because it is wide enough to be seen and yet physically light.

I have previously epoxied paracord loops into the open ends of carbon shafts and it works great. Five-Minute stuff is just right for this.

 

[Beendare]

Yeah, I've used those fences before with the fiberglass poles. Seems like a lot of work with ehe inserts and allthread when the Alu tent poles come with fitting that slide on and they are stiffer than my Axis 300's. Hey, i know how it is when a guy wants to make something....no doubt it will be a cool setup.

 

[Kevin Dill]

Not really too much trouble when you enjoy a good diy project. I just ordered the 8-32 stainless all-thread and will have it in a few days. My initial web research tells me that carbon arrow shafts should not be trusted to be electrically non-conductive, so insulators of some sort will be a requirement. I still think those will be rubber tubing verified to be non-conductive, OR another contender is heat-shrink tubing which is nonconductive.

 

[rayporter]

i would bet the heat shrink will not work on a conductive post. pretty sure- unless you can find something special. i wrap wire with old fashioned friction tape [colth ] and then put the heat shrink over it to get it non conductive.

now if your carbon is only slightly conductive you will have a winner. it should be easy enough for you to test by sticking five arrows in the ground in a four foot span and the wrap each with a piece of real wire and hook up a fence checker too see how much is lost.

my TSC [or any farm supply ] carries coated wire to bury that has extra thick insulation to stand the hi voltage around water.

an fyi for those new to this. keep your insulators clean. mine are up all year for livestock and they get dirt and dust on them and after a heavy dew you can hear a spark at just about each one in the morning. it is my guess that is how the critters know if it is on or not.

another tip. i use the poly wire away from the house instead of the tape for convenience. the tape just takes up too much room on a ski rope winder. but the poly wire can be unwound through the bushes in a few minutes by just walking along and wound up the same way very quickly. i dont use insulators for horses. i cut and modify by tieing the poly a bunch to customize for different size pens. the voltage does not pass through the knots well. for your purpose keep the knots to a minimum. the tape is worse about passing voltage than the string.

i have not handled the tape with a hot wire and a ground wire in it so i can only speculate that problems will arise. the opportunity for shorts will be high. i can see the positives of it, too. but a good way to roll and unroll will be important. the ski rope winder is handy.

keep building-ray

 

[Beendare]

Kevin, any update on how your post is working?

 

[Kevin Dill]

Although slow to be completed, everything is working nicely. Carbon shafts are cut and set up to make 3-pc posts. After talking to my local electrical supplier and an electrician I was assured that heat shrink tubing is nonconductive unless specifically identified otherwise. I'll be applying a 4" section of heat shrink tubing to use as an insulator. I can then simply wrap the e-wire (tape) 360 around the post over the tubing and continue to the next post. I know this will work great and also speed/simplify the installation. Except for a few small miscellaneous things, my fence package will consist of the Speedrite AN20 Energizer, a compact roll of 1" wide equine tape, and a small bundle of 18 post sections which are 15" long. My goal was to make this thing light, simple and compact. I think it will be exactly that when completed.

 

[colonel00]

Are you planning to ground the energizer or just have a ground wire running the perimeter?

I'm also interested in what the final package weight will be. My "small" package comes in at 2lbs 14oz.

This allows for a three wire setup which the top and bottom wire are positive while the middle is a ground along with a ground stake.

 

[Kevin Dill]

My plan is to go with 2 rounds of the 1" equine tape and use the ground from the energizer. The tape weighs more than simple wire, but visibility in the dark is a critical component of success I believe. Any animal which sees the wire is far more likely to intentionally touch it with a nose or lick it and get an excellent shock. Animal hair isn't the best conductor, so I don't want them to get into the fence before finally getting shocked. I don't know exactly how the carbon shafts will compare to the green plastic/fiber shafts, but I'm guessing they (carbon) won't be any heavier and might be lighter. The 15" breakdown will be nice for packing. I'm building enough shaft sets to do a 6-post hex shape if desired, but can drop down to 4 posts for lighter weight. 90 degree square corners are not nearly as stout as a hex shape, with 4 corners bearing 25% (each) of the inward pull, while 6 posts bear around 17%. I've tested both designs and the hex yields less bowing and sagging. Also, every complete round of wire increases the inward pull dramatically which is another reason I'm going with 2 rounds of the wider tape. Lastly, I've had much better results inserting the posts with an obvious outward lean. Doing so allows me to put good tension on the wire and create a bow in each post which will serve as a type of automatic tensioner. I'm interested in your thoughts and comments.

 

[ndbwhunter]

How is the project coming along?

I've been looking at the various components needed to build a fence like this, but I'm still trying to find a good insulator for the poles. I'm either going to use carbon arrows or aluminum tent poles from tentpole technologies. This poly tubing seems like it would work well if a person could figure out a good (lightweight) way to attach it.

http://www.tractorsupply.com/en/store/zarebareg;--4-in-fin-tube-insulator?cm_vc=-10005

One thought that I had using the above insulator was to incorporate the insulator mounting system into the joint between the two poles. In your case, using the carbon poles and all-thread connection, you could use a piece of aluminum flat (1/8" x 3/4")with a hole in each end. Stick the flat over the all-thread, and screw the pole sections together. Then, using the other hole in the flat, you could ziptie the poly tube to the flat. The only downfall to using this type of mounting system would be the inability to adjust the height of the wires. Does this seem like something that would work?

Disclaimer: I am extremely handy-tarded when it comes to electricity, so any criticism would be greatly appreciated.

 

[Kevin Dill]

How is the project coming along?

I've been looking at the various components needed to build a fence like this, but I'm still trying to find a good insulator for the poles. I'm either going to use carbon arrows or aluminum tent poles from tentpole technologies. This poly tubing seems like it would work well if a person could figure out a good (lightweight) way to attach it.

http://www.tractorsupply.com/en/store/zarebareg;--4-in-fin-tube-insulator?cm_vc=-10005

One thought that I had using the above insulator was to incorporate the insulator mounting system into the joint between the two poles. In your case, using the carbon poles and all-thread connection, you could use a piece of aluminum flat (1/8" x 3/4")with a hole in each end. Stick the flat over the all-thread, and screw the pole sections together. Then, using the other hole in the flat, you could ziptie the poly tube to the flat. The only downfall to using this type of mounting system would be the inability to adjust the height of the wires. Does this seem like something that would work?

Disclaimer: I am extremely handy-tarded when it comes to electricity, so any criticism would be greatly appreciated.

Coming along nicely. The carbon shaft/insert/all-thread concept is not hard to create and works well. Nothing to lose or hassle with. I gave insulators a lot of consideration before deciding to go dumb-simple. Heat-shrink tubing on the shaft means I can place the wire-tape directly against the tubing. I can do a 360-wrap at each post, or I can simply tie the wire-tape to the shaft. I originally thought about poly or rubber tubing, but heat-shrink is absolutely non-conductive and easier to apply. Game over. Although valid, I also personally wouldn't be in favor of the extra aluminum and poly-tubing pieces to manage. It would be easier to go with screw-on plastic insulators I think. Also, the poly-tube won't work with the wider equine electrical tape-wire.

I can't see how it gets much better for sturdiness and simplicity/minimal parts. The carbon shafts are stout but can flex some. No separate insulators to deal with or break. All parts are easily available if I lose or damage something somehow. Now...if someone could invent a stronger energizer that weighed 50% less and used lithium-ion batteries....wouldn't THAT be a humdinger?

 

[ndbwhunter]

Coming along nicely. The carbon shaft/insert/all-thread concept is not hard to create and works well. Nothing to lose or hassle with. I gave insulators a lot of consideration before deciding to go dumb-simple. Heat-shrink tubing on the shaft means I can place the wire-tape directly against the tubing. I can do a 360-wrap at each post, or I can simply tie the wire-tape to the shaft. I originally thought about poly or rubber tubing, but heat-shrink is absolutely non-conductive and easier to apply. Game over. Although valid, I also personally wouldn't be in favor of the extra aluminum and poly-tubing pieces to manage. It would be easier to go with screw-on plastic insulators I think. Also, the poly-tube won't work with the wider equine electrical tape-wire.

I can't see how it gets much better for sturdiness and simplicity/minimal parts. The carbon shafts are stout but can flex some. No separate insulators to deal with or break. All parts are easily available if I lose or damage something somehow. Now...if someone could invent a stronger energizer that weighed 50% less and used lithium-ion batteries....wouldn't THAT be a humdinger?

Where are you getting the heat shrink tubing? The only heat shrink tubing that I've used has been pretty thin, and doesn't seem like it would work well. How thick is the stuff you're using? Can you post links to the sites that you're getting all your stuff from?

 

[Colberjs]

Where are you getting the heat shrink tubing? The only heat shrink tubing that I've used has been pretty thin, and doesn't seem like it would work well. How thick is the stuff you're using? Can you post links to the sites that you're getting all your stuff from?

You can buy heat shrink at Lowes ot probably any automotive parts house.