Planting poles with a concrete foundation can be a messy business. Avoid cement wastage by using a steel plate for mixing, and ensure uniform holes with an L-shaped frame.
You don’t need a degree in chemical engineering to cast concrete foundations for poles, but it is a time-consuming activity and, if you are working in sandy conditions, there is the associated wastage and mess.
Ben Vorster, a part-time game farmer and contractor from Northam in the Limpopo province of South Africa has saved his friends in the Kalahari hours of frustration with his bent steel plate for cement work, and his L-shaped frame (template) used for digging uniform holes.
Using these two aids, better estimates can be made for cement work and equal quantities of cement can be used in each hole. They also ensure neat, uniform holes and prevent sand or soil from the edge of the hole landing up in the cement.
Ben likes working with his hands. His business keeps him very busy, but if he gets any free time he likes to restore old furniture.
A friend in the Kalahari invited him to come and visit and it was there in the desert that he came up with this plan. He realised that the sandy soil in the Kalahari is a different challenge to the peaty soil he was accustomed to in Northam in the Bushveld.
MIXING PLATE SAVES CEMENT
When cement, river sand and stone is mixed, soil or other debris often gets mixed in. Sometimes there is cement left over that can’t be carried to the next hole.
To remedy this, Ben made a mixing plate of 1,6mm steel (1.6m x 2.4m in size). He bent the plate lengthwise, 400mm from each side, to form a chute (see how to bend the plate, below). He welded round steel at each corner to serve as handles.
Two or four people can carry the mixing plate from one hole to the next. It can also be loaded onto a pick-up truck or a wheelbarrow to utilise any remaining cement.
The texture of the sand, stone and cement that is mixed on this plate is smooth.
The last bit of the mixture that is put into the hole doesn’t contain much soil or other undesirable material (such as grass or manure when working near cattle pens), unlike when the concrete is mixed directly on the ground. This unwanted grass and soil reduces the strength of the concrete and looks messy.
“Twice as many poles can be planted in the same time using this method, it saves time and money, especially for those doing large fencing projects or erecting kraals.
HOW TO BEND THE MIXING PLATE
Attach an angle iron (weld or clamp) 400mm from each side of the steel plate. Use an angle grinder to cut a shallow groove in the plate so that it is easier to bend. The angle iron acts as a support to bend the plate in a straight line, and also keeps the cutting disc in the right place.
Once the plate has been bent, the groove can be welded at a few places to reinforce it once again. Because the plate is bent, it reinforces itself and can carry a reasonable weight says Ben.
STEEL TEMPLATE AROUND HOLES
Ben manufactured two L-shaped frames from 25mm square tubing with a 1.6mm plate welded onto them. When the frames are placed at 90-degrees to each other, they form a square with a hole in the middle and this serves as a measurement for the hole size that has to be dug (you can obviously make different sizes according to the poles that have to be planted).
After the holes have been dug, you would place the L-templates around the hole with the mixing plate above so that the cement can be cast without debris falling in, he explains.
“The people working around the hole will also be able to work more effectively because they can stand sturdily and keep their balance.”
To protect the poles from rust and weathering it is a good idea to slope the cement upwards at the bottom of the pole, and to ensure that the cement is above ground level. “Rainwater dams up in puddles in cattle pens and it causes the poles to rust more quickly,” says Ben.
CEMENT PEDESTALS PREVENT RUST
In areas with clay soil where rain regularly puddles and dams up around the support poles causing rust, you could raise the cement even more with an old proven farmers’ patent.
Cut a plastic bucket open at the bottom and put it over the pole as soon as the cement is at ground level. The upside-down bucket is then filled up. Once the cement has set, you lift off or cut off the bucket.
Another piece of advice is to fill the top of the support poles with cement to prevent rainwater from damming up. A sack or newspaper is pushed in the top to prevent the cement falling to the bottom of the pole as it is put in. Some farmers will actually fill the pole completely to strengthen it.
ENQUIRIES: Ben Vorster, e-mail – firstname.lastname@example.org