PLASTIC DROPPERS

Why should you buy our hollow fence droppers?

Polyfence is synonymous with quality and our Plastic Fence Droppers are one of the plastic fencing products that we are very proud of. Our Fence Droppers are superior to any other plastic droppers on the market. We designed them to present the market with a viable alternative to steel droppers. Our hollow plastic droppers comply with all necessary criteria as the perfect fence dropper solution, as follows:

• They are lightweight and inexpensive.
• They are not affected by any weather conditions, including acid-rain.
• They are strong, resilient, extremely durable and maintenance-free.
• They are resistant to most chemical solvents including pesticides and animal urine.
• They are an environmentally safe product that does not release harmful toxins into the environment.
• The internal reinforcement of our hollow droppers ensures their strength and rigidity, yet with sufficient resilience to withstand a relatively high side impact of accidental contact by animals
• They maintain their straight shape and will not warp due to intense sunny conditions, such as the problem of solid plastic droppers.

Problem with Steel Droppers

As a product there is nothing wrong with steel droppers and they still present one of the best fencing post options. The problem is that steel theft in South Africa is and will always be a problem. Hence the search for alternative fencing pole options

Quality Plastic Fence Droppers At Polyfence

We soon realized that in order to replace steel droppers we needed to create a quality alternative. An enormous amount of research has gone into the creation of our plastic droppers. The result of years of tests is a complete product that is innovative, versatile, resilient and durable. Our fence droppers are no normal plastic poles. It is totally unique in structure and make-up.

Lightweight fence droppers

Our plastic fence droppers are much lighter than traditional steel and wooden droppers. It is therefore much easier to handle and transport.

Construction of our fence droppers

On our fencing products features and benefits page you will learn about the strength, durability and toughness of all our fencing material, especially our plastic droppers. The way that the fence droppers are constructed plays just as big a role in its strength and durability as the fact that the product is made from HDPE.

Our droppers are casted into pipe form which makes them hollow. This ensures the ventilation capabilities of the dropper. The hollow droppers are moulded with transverse material strips that run all the way down the inside of the pipe. This kind of structure increases its strength and rigidity. It prevents droppers from being compressed when it comes under pressure from the wires that are fixed to it. The construction of the pipe with the ventilation effect of its hollowness ensures that it will never lose its shape in the intense heat of our South African climate.

Air can constantly flow through the dropper and the hollowness enables it to “breathe” in humid and hot conditions, thus ensuring its rigidness. With solid droppers 50% of the dropper surface is exposed to direct sunlight and it must constantly absorb this heat. With hollow droppers only 25% of the surface is exposed to direct sunlight and the flow of air through the hollow fence dropper cools the dropper and helps with UV resistance. Constant exposure to sunlight eventually takes its toll on solid droppers as they become soft. This leads to them becoming a strain on the fence. (see our example of our Polyfence dropper’s vs solid dropper installation)

PVC vs HDPE Droppers

We do not sell just any type of plastic product. Our fence droppers can not be compared to any other plastic droppers. You should do careful research as to what type of plastic is used when you buy your droppers. PVC is a vinyl polymer plastic that is low cost, durable and is often used in construction. It has a high tensile strength and it is lightweight. It is widely used in the production of pipes, both for above and underground usage. High density polyethylene (HDPE), is a thermoplastic that is made from petroleum. HDPE is used in a variety of applications and industries where excellent impact resistance, high tensile strength, low moisture absorption and chemical and corrosion resistance properties are required. PVC is generally not suited for use as fence posts. According to thermofischer.com the glass transition temperature of HDPE is -25ºC, whilst PVC is way higher at over 70ºC. PVC therefore exhibits much lower impact strength at room temperature. PVC is heavier and stronger, but HDPE is harder and more abrasion resistant. Droppers and other fence posts designed from HDPE show a much lower fail rate compared to PVC posts, when they are subjected to harsh elements like rain, cold, heat and wind. HDPE is more resistant to salt, corrosive materials and abrasion from sand, straw and dust, making it ideal for farm purposes.

Impact Resilient product

When animals run into or kick the fence dropper it is resilient enough to absorb the impact and immediately return to its original position.

In a book by George A Antaki called “Piping and Pipeline Engineering: Design, Construction, Maintenance, Integrity and Repair” p.68, it is explained that a condition called “plane strain” specifies that the thicker the part, the more constrained is the material at its center and the lower its toughness. Toughness is the ability of a material to absorb impact energy prior to rupture. Polyfence dropper wall thickness is small, which greatly enhances our product’s toughness according to this theory. We are interested in the impact from the outside and according to the theory the thin walls (see wall thickness on our dropper product page) make it more tough. If the inside of a pipe is subjected to pressure, a thicker wall would be more beneficial. The thicker the wall in our case, the more it would be prone to brittle fracture, and the higher its minimum operating temperature.

Why Tensile Strength is not important when it comes to Droppers?

The tensile strength of a material is its capacity to withstand stretching forces until it fractures. Fence droppers are not subjected to any longitudinal forces. Its tensile strength is therefore not a priority factor.

Fire Retardant Fence Droppers

Like with all our other Fencing posts, special flame-retardant additives are added to our HDPE Droppers to enhance their resistance to fire. According to thermofischer.com the maximum usages temperature of HDPE is 120ºC. This is considerably higher than the PVC products that ranged between 79 and 85 ºC. They also indicate that HDPE would start melting at between 125-138 ºC. Our special flame-retardant additives ensure that the fence droppers can withstand temperatures of up to 180 ºC before it starts to deform, 220 degrees before it melts and 300 degrees before it burns. The design of the droppers furthermore assists in slowing down the burning process. The flow of cool air through the hollow dropper also makes it more fire resistant, because it slows down the build-up of temperature. Veldfires are one of the main destroyers of farm fences. Unfortunately, plastic will burn at some point. The construction of our plastic droppers with their hollow nature and the combination of HDPE and special flame-retardant additives ensures that Polyfence droppers will survive low intensity veldfires.

Use of Droppers in Electrical Fencing

Steel and Wooden fence posts are not ideally suited for use in electric fences. Our plastic droppers are very suitable for use on electric fences. It is manufactured from High Density Polyethylene which means that it does not absorb water and water does not cling to it. It is non-conductive. There is no need for isolators and the electric wires can be connected directly to the droppers with binding wire.

Polyfence Plastic Fence Droppers: An Eco-Friendly Product.

Polyfence Droppers are designed from HDPE. High Density Polyethylene is commonly recycled and made into plastic lumber. HDPE is a type 2 plastic and is generally considered Eco-Friendly because they are made mainly from post-consumer products and are recyclable at the end of their useful life. At Polyfence we use recycled HDPE to manufacture our products thereby contributing to a green environment.

Extremely weather resistant

Our special patented formula that we use in the design of our plastic fence droppers protects the product against the elements. HDPE is generally not UV resistant, but our product is extremely UV and Acid Rain resistant. It is constructed from HDPE and is therefore highly resistant to most solvents including water. Our Droppers need no paint, will never rust and will not weather. Test were done on our fence dropper and Y-standard replacement pole. The test simulated extreme hot dry and wet conditions for a period of 10 years. The test results showed that the product still looked new and that no evidence of chalking or cracking was evident. It was concluded that the product would last many years more under outdoor conditions.