10 replies to this topic

[jay-uk]

Hello

Can anyone tell me the best price and location/s to buy concrete poles to put around a piece of farm land? The woden posts only last a couple of years I'm told and most secure way to keep animals in/out is concerete cement poles. I sort of remember someone telling me a few years back 100 baht per piece is that accurate. If you have wire price also it would be appreciated. Thank you.

[WatersEdge]

I make my own concrete fenceposts.
2 sticks of rebar in a post 10x15 cm x 3 meters long.
Buried 1 meter in the ground
Standing 2 meters tall.
6 strands of barbed wire spaced 30 cm apart
30
60
90
120
150
180

For goats we attach shade cloth to the barbed wire,
because if a goat can get his nose through,
the whole animal will follow.
Barbed wire fences mean nothing to a herd of goats
Initially we put 1 meter shade cloth on the bottom of the fence,
but then the goats learned to leap over the shade cloth between the barbed wire,
so we now cover the full 2 meters solid in shade cloth
The solid shade cloth fence also makes it easy to see if a thief has broken onto the property.
With it fastened on the barbs, there is no way to get through without damaging the cloth.
Yes it can be easily sliced, but then it's also obvious that is has been cut.

We use 2x4 inch 5x10 cm rectangular tube for forms,
10 sticks 6 meters long as forms allow us to make 18 posts per day.
If you have more open flat slab you can easily pour several times a day,
stripping the form tubes out from between the wet posts
but the posts can't be picked up for a full day, two days is safer

It is best to lay a tarp on a concrete slab,
so that fresh concrete does not stick to the slab.
We also have made precast concrete panels

The rebar must be suspended on a wire,
exactly in the middle of the form height.
If the rebar is not on center,
then the posts break very easily.

They also work well for pump base foundations, fuel barrel stands,
plenty of homes for a broken fence post.

Over the past three years we have made perhaps 500 posts.
It is really nice to never worry about a termite.

Barbed wire costs around B500 per roll of 100 meters.
I think it is sold as 5kg and 10 kg rolls rather than according to length,
but a 10kg roll also happens to be around 100 meter

I use 10mm ribbed rebar, because that is what I bought a whole truckload of at once.
smaller would work just as well.
One stick exactly in the center would probably work fine as well.
A fencepost doesn't do any work once it is in position,
just supports 3 meters of wire.
We space the posts 3 meters apart,
but if the wire is tightly stretched,
wider space would be fine.

These posts weight 108 kg each,
so you will need a couple of good men to handle them.
Once they are in position, they are not stolen either.

Attached Files

•  DSC09851.JPG   320.27K   150 downloads
•  IMG_3284.JPG   2.1MB   148 downloads
•  Fence_Post_Cross_Section_20071024.JPG   31.34K   93 downloads

[jay-uk]

Thanks for the information which is great in terms of options. I have been working on the assumption that we need to spend between 100-150 baht per post at a similar length to yours. How does this compare on cost to making them yourself as my brother-in-law is prepared to have go casting them himself. Do the posts need wire reinforcement through the centre to stop them from being brittle etc...

Cheers.
Jay

[nakachalet]

watersedge

congrats.... that surely is a piece of rare art work....

but why did you make such huge posts, 108 kg/per....?

are there much wild animals around your moo-baarn?

anyway, what is your average cost per post, pls?

cheers, thx

[WatersEdge]

They do need rebar reinforcement,
but the two sticks of 10mm ribbed rebar I use is excessive

Smaller rebar would be adequate and 1 stick might be adequate if it was precisely on center.

Initially we built 4x4 inch 10x10cm posts with one rebar
Had our material quality been good they would have been fine,
but we had river gravel available with round stones in it
If you have nice crushed stone it holds together better.

Precast manufacturers make small posts, even smaller than 4x4 inch

I attached a spreadsheet calculator for posts.

Note that 10 bags cement per cubic meter aggregate is excessive as well.
You could very well use 4 bags/m3 if your crushed stone is good.
This reduces the costs below to
B129 for 4x6 from B167
B 87 for 4x4 B 98

The form steel is an investment,
but hopefully you have a final use for it after the posts are built.
2x4 inch rectangular tubing 6 meter sticks cost around B800 each
If you have only two form sticks, you can still build 6 posts per day, pouring every 8 hour

You will probably find as I did,
once you start making posts for yourself,
neighbors will want to buy them from you.
If you have detail conscious workers, then precast concrete is good business.
Because they are heavy, the more remote the location, the more you stand to earn.
Everyone can understand the advantage of termite immune

I did not explain one detail.
we push 1/2 inch PVC pipe into the wet concrete after poured,
at the correct 30cm spacings
measuring from the top,
20
50
80
110
140
170
so that wire can attach barbed wire to the post.
These are pulled out after the concrete is firm enough to not slump.
If you wait until the concrete is dry,
you may not get the pvc out for another use.

We still need steel fenceposts in Thailand,
the cheap T-iron cross section with the little nubs for holding the wire at the correct height.
The pipe slide drivers that pound them into the ground quickly
The problem I foresee with them in Thailand...they are very tempting theft targets.
No one bothers to steal a 108kg concrete post.
All the same, can someone who knows a steel mill recommend they make a million of them?
They are made from the same grade of steel as rebar...nothing fancy.

We also need a good method of attaching electric wire
Does anyone have a source of the cylindrical ceramic insulators with a nail hole down the center?
They are around 1 inch diameter and 2 inches long... 25 & 50 mm for you who have seen the metric light.
The insulators available locally are huge, more suited to city power lines, and expensive
I know now that goats would respect one tiny galvanized high voltage low amperage wire
more than all the barbed wire and shade cloth
Electric fence is also the key to feeding animals in the field.
Rather than carrying heavy feed to the animals, let the animals walk near the feed to a temporary electric enclosure.

Attached Files

•  Fence_Post_Calculator_20090913.xls   12K   40 downloads
•  Steel_Fence_Post.jpg   1.8K   6 downloads
•  Fence_Post_Driver.jpeg   1.14K   5 downloads

Edited by WatersEdge, 2009-09-13 08:38:07.

[Pond Life]

One or two pieces of re bar is fine if your using 10 mm steel & a strong concrete mix..
But if youre buying from someone who makes them commercially they will use two piece of 3.2 or 4 mm steel.
& the concrete mix will be the cheapest/weakest they can get away with.
This means that the posts are very weak in one direction & ok in the other.
Spend the extra Baht & get them to make special ones with 4 pieces of steel.
This will bump the price up to say 180 B from 120 B.
But you dont have to break to many 120 B posts before you wish you'd spent the extra cash.

[nakachalet]

THX much for valuable info.

we'll give it a try tomorrow.

[finner]

Does anyone have a source of the cylindrical ceramic insulators with a nail hole down the center?
They are around 1 inch diameter and 2 inches long... 25 & 50 mm for you who have seen the metric light.
The insulators available locally are huge, more suited to city power lines, and expensive
I know now that goats would respect one tiny galvanized high voltage low amperage wire
more than all the barbed wire and shade cloth

WatersEdge, why not just leave one of your PVC pieces in your concrete pour at the height you want the electric wire to be at and just put a Tee on it to carry the wire from post to post. It might be a good idea to make sure the PVC piece is loose in the hole in case it gets broken and has to be replaced. What voltage is the wire at?

[WatersEdge]

Yes, your solution is well received.

I at first doubted the resistivity of PVC,
but googled it at your mention,
to be reminded that electrical cable insulation is PVC
a very thin cover holds 600V standard rating, likely far beyond.
We still need a bit of standoff distance,
because electric fences are a great deal more than line voltage
but I'm thinking 10 cm is sufficient.
By the way, PVC Resistivity is 10Power16 Ohm-cm
http://www.pvc.org/W...characteristics
Bravo...problem solved....many thanks.

Electric fences are high voltage low amperage,
very unpleasant but no health hazard in common sense conditions
I say common sense because certain foolhardy individuals
have attempted situations of bravado in response to a dare
which risks their participation in the gene pool.
In the order of 100,000 volts, give or take 20,000
They are a DC pulse, time between pulses dependent on the sender unit.,
but something like 3 seconds.

Slapout wrote about a "weed burner" fence that was a lot more potent.
His early days were in Oklahoma cattle country
He said it knocked calves down....once...and they never touched it again.
That's more fence than I'm looking for, but it does appeal as theft prevention.

[slapout]

The weed burner fence was plugged into 110 volt outlet, protected from weather of course. We used this for permanent electric fence around pasture, normally attached to the normal 5 strand barbed wire (it would keep bulls from walking thru a fence to get to cows). Temporary electric fencing around grain crops was normally powered by standard 12 volt auto/truck battery. This will keep cattle in if they have plenty of water and grazing.

[onlydhanoa]

Typically, a batch of concrete can be made by using 1 part Portland cement, 2 parts dry sand, 3 parts dry stone, 1/2 part water. The parts are in terms of weight – not volume. For example, 1-cubic-foot (0.028 m3) of concrete would be made using 22 lb (10.0 kg) cement, 10 lb (4.5 kg) water, 41 lb (19 kg) dry sand, 70 lb (32 kg) dry stone (1/2" to 3/4" stone). This would make 1-cubic-foot (0.028 m3) of concrete and would weigh about 143 lb (65 kg). The sand should be mortar or brick sand (washed and filtered if possible) and the stone should be washed if possible. Organic materials (leaves, twigs, etc) should be removed from the sand and stone to ensure the highest strength.

Care needs to be taken to properly cure concrete for strength and hardness. This happens after the concrete has been placed. In around 3 weeks, over 90% of the final strength is typically reached, though it may continue to strengthen for decades.
Hydration and hardening of concrete during the first three days is critical. The early strength of the concrete can be increased by keeping it damp for a longer period during the curing process.

Properly curing concrete leads to increased strength and lower permeability, and avoids cracking where the surface dries out prematurely. Improper curing can cause scaling, reduced strength, poor abrasion resistance and cracking.