What is vinyl, and what is the difference between PVC and the vinyl used in fences?
Crude Oil, Natural Gas, and Salt are the raw materials used to produce Poly Vinyl Chloride (PVC) Resins. The simplistic term "PVC" can encompass anything from a soft plastic lawnchair to the incredibly strong types used in military armor and by NASA. Southwest Vinyl uses vinyl compounds formulated from premium grade raw materials, which include Poly Vinyl Chloride (PVC) Resin, UV inhibitors, impact modifiers, stabilizers and toners. Southwest Vinyl's product line includes Kroy's 40-plus years of technical experience in the high-density vinyl polymer industry. Using only premium grade raw materials in conjunction with superior technical formulation capabilities produces a vinyl product far above industry standards.
How is PVC manufactured?
The basic chemicals used in manufacturing PVC – ethylene and chlorine – are derived from materials nature provides. Ethylene is made from crude oil or natural gas and chlorine is made from salt. These gases are chemically reacted to form ethylene dichloride (EDC). The EDC is heated, or cracked producing two gases, hydrogen chloride (HCl) and vinyl chloride monomer (VCM).
Vinyl chloride monomer is the basic building block used in the manufacture of polyvinyl chloride. The term poly means many. PVC is simply many molecules of vinyl chloride. High Density Vinyl Polymer is many layers of these molecular structures.
A chemical reaction called polymerization is used to convert VCM into PVC resin. This is accomplished by making VCM react with itself to form a powdery white solid material – PVC resin. Once PVC resin is produced it cannot revert back to VCM. Much the same as cooking an egg – once cooked, it cannot return to its original, raw state.
PVC resin is blended with a wide variety of ingredients such as stabilizers, colors, processing aids, UV inhibitors and plasticizers to produce compounds in powder or pellet form. Products made from these compounds have an almost infinite range – from rigid PVC pipe, which has no plasticizers, to very flexible vinyl products such as upholstery and wall coverings. (Source: PVC and Fire, Vinyl Council of Canada)
How is vinyl fence made?
Profiles: Vinyl fence starts out as a PVC powder (Resin) that, when blended with all the required ingredients, resulting in a compound. This compound then is fed into an extruder. With the proper amount of heat, pressure and mixing, the compound becomes malleable vinyl. This vinyl is then fed through a die in the shape of the finished profile. Using vacuum technology to keep the pliable vinyl in the proper shape, water is used to cool the vinyl into its final rigid state.
Fabrication: A Southwest Vinyl Fence fabricator cuts the wide variety of picket or slat profiles to custom lengths for the desired design. Special notches are then crimped into the picket tops and bottoms. The fabricator then routers individual holes into the rails so the notched pickets can be inserted and locked into place. Posts are then routered to match rail profiles. The various fence components may then be assembled as a complete fence or separated for shipping.
These carefully crafted, interlocking components are an additional reason why custom vinyl fencing is superior to the "big box," stores. National chains such as Home Depot, Lowes, Harvey, and Direct Buy do not carry, stock, fabricate, resize, or assemble vinyl fencing. Their market is not the custom, lifetime vinyl fence customer. These all-in-one stores offer a catalog from which to order prefabricated sections of fence. Glued and screwed, pre-fabricated plastic sections, put together with brackets and screws cannot, and are not, meant to last a lifetime. A customer should be encouraged to research the difference. Customers are often surprised that an installed, custom, lifetime, vinyl fence may only cost 10-20% more than having a chainstore hire someone to install prefab plastic fence sections.
What type of Extrusions are used in vinyl fence?
Two types of extrusion processes have typically been used in the production of all types of High Density Vinyl Polymer extruded products such as Siding, Window and Door frames, Pipe and Fence products: Monolayer and Co-extrusion. A Fence buyer should be aware of what specification is being used by an extruder, as many fence extruders are producing fence product using a pipe specification, which has lower demands for UV stabilization and impact resistance.
What is Monolayer Extrusion?
A single extruder is used to form the desired shape of a profile. Since this is a single layer extrusion, the formulation characteristics are uniformly dispersed throughout the overall thickness of the profile.
What is Co-Extrusion?
Co-Extrusion is a more recent advancement in extrusion technology which brings 2 layers of High Density Vinyl Polymers into play: The outer layer, or Cap Stock, is similar to human skin, and contains a denser concentration of the essential elements, such as the UV inhibitors (much like sunscreen), which is only doing its job when exposed to UV rays. ASTM's "Specification for Rigid PVC Exterior Profiles Used for Fencing" (F 964-94) requires that the cap stock layer be a minimum of 00.015" thick and a maximum of 20% of the overall thickness of the profile wall. It is important for the potential buyer of a High Density Vinyl Polymer fence, deck, or railing system to determine what ASTM specification is being used by his potential extrusion supplier, if in fact any is being used at all, and to ensure that compliance is being verified regularly.
The inner layer, or Substrate layer, when produced with virgin raw materials, is essentially the same as the cap stock layer, but with a lowered concentration of UV inhibitors and color pigment. This allows Kroy manufacturing to formulate a better molecular bond via the impact modifiers in the substrate compound resulting in a stronger product.
What if my co-extruded fence product has a color difference?
One of the popular misconceptions is that a color differential between the cap stock and the substrate indicates "regrind" in the substrate, when it may not necessarily be so. Color pigments may be decreased in a virgin substrate compound which would give it a different hue. Conversely, a "regrind" substrate may be the exact same color as the cap stock, leaving one with the impression that the product was mono-extruded.
Isn't a co-extruded product inferior?
Another misconception is that co-extrusion is inferior to monolayer. Co-extrusion is a newer and more capital-intensive technology offering significant benefit to the consumer by concentrating the essential materials where they do the most good. This gives the consumer a stronger, more durable product, and in turn, more overall value.
Claims of inferiority of the high-tech co-extrusion process usually come from manufacturers who are hesitant to make the significant capital investment for additional extruders and specialized profile tooling, or have built their reputation on defaming this advanced extrusion technology.
Won't a co-extruded product delaminate?
Some claim that the layers in co-extrusion may delaminate. Co-extrusion is not lamination. Lamination is a process whereby adhesives are used to bond two layers together. Co-extrusion is a molecular bonding process without the use of adhesives, it is accomplished at high pressure and temperatures in a sealed environment where no moisture or air can be entrapped to compromise the molecular bonding, making it impossible to separate the layers.
How is vinyl fence put together?
Most assembly of vinyl fencing is done by locking the rails into the post, using rails that are tabbed with a special tabbing, or notching tool, called a crimper. Depending upon the style of fence, different fasteners can be used. When screws are required for weight-bearing gate hinges, they are screwed into internal metal support structures, "sandwiching" the vinyl for added strength.
Will a Southwest Vinyl fence mildew?
Mildew feeds off of organic materials like wood. High Density Vinyl Polymer is non-organic and does not support mildew. Unlike porous materials such as brick, block, or wood, Southwest Vinyl fence profiles have a very smooth, high-gloss, non-porous, non-chalking surface. Dense vinyl polymer, infused with TiO2 (titanium dioxide), helps to prevent mildew by making it difficult for organic materials to attach. A consistently damp and dirty surface can provide enough material for mildew to get a start, but a mild solution of bleach and water should easily remove it.
Does Southwest Vinyl Fence chalk?
Chalking is a term used for describing the deterioration of vinyl surfaces, especially older types of vinyl. Exposed titanium dioxide particles (TiO2) would appear as a white powder which could be wiped off the surface. Southwest Vinyl's use of high grade, non-chalking TiO2 ensures that there will be virtually no chalking of product surfaces. All vinyl fencing will "technically" chalk sooner or later, but with the superior protection capabilities of sufficient TiO2, this is usually not detectable. Southwest Vinyl's product lines are formulated for exceptional beauty over a lifetime.
Can I paint my vinyl fence?
Southwest Vinyl's products are engineered to retain their beauty and good looks for life, without painting or maintenance. Southwest Vinyl Fence does not recommend painting vinyl products. Although there are "vinyl" paints available, painting or otherwise treating the product lines that Southwest Vinyl carries will typically void the lifetime warranty.
How does the cost of vinyl fencing compare with traditional fences?
Vinyl costs less than unsightly cinderblock in most parts of the country. In addition, no cinderblock manufacturer will warranty block or brick as it will eventually crack, erode, and lose its mortar over time. Block eventually has to be replaced at high cost. Also, if block is ever painted, it becomes an expensive, high-maintenance, nuisance cycle--continually trying to match paint lots and finishes.
The initial cost of vinyl when compared to wood is slightly higher for material in most regions of the country. However, with the ever-increasing cost of wood, this difference is becoming a non-issue in much of the country. When all of the cost factors are taken into account over the life of your fence, vinyl becomes the true money saver. The higher cost of wood includes having to routinely replace warped or broken wood pickets, yearly maintenance costs for paint, stain, waterproofing, labor, etc., and replacement of the entire fence every decade or two. When the detrimental environmental effects of wood processing are considered, along with the toxic chemicals needed to maintain wood, it becomes clear why so many states are encouraging High Density Vinyl Polymer as THE green fencing solution.
Wood is truly not as cost effective as it might first appear, and some costs are hard to measure; such as the loss of property value when a fence is in need of repair or painting.
The initial cost difference between vinyl and any other kind of fence vanishes in a short time, and, in fact, vinyl becomes THE most sound and financially viable fencing option.
Once your Southwest Vinyl fence is installed you'll never again have to bother with waterproofing, treating, stripping or painting. No more rusting nails, chipping, cracking, replacing rotting boards, insect damage, or splinters.
Will my vinyl fence turn yellow?
Southwest Vinyl Fence manufacturers use only superior, durable grades of non-chalking TiO2, protecting the vinyl from the harmful effects of the sun's UV rays. As long as your fence is kept clean, with a periodic wash from a garden hose, any fading or discoloration will be slight and uniform--much like kitchen linoleum fading that is only noticeable when the cabinets are torn out for a remodel.
What effects does my vinyl fence have on our environment?
Modern High Density Vinyl Polymer fencing products are safe and non-toxic. They do not breakdown and release harmful chemicals into the ground and or require toxic chemicals for their maintenance; such as stains, oils, waterproofing, paint, and thinner. Trees are spared with the use of a vinyl fence. Because of the exceptionally long life of high-quality vinyl polymer, one "Lifetime" vinyl fence will typically outlast anywhere from four to six wood fences. In addition to saving wood, and money, if a Southwest Vinyl fence ever needs to be taken down it can be recycled into other products such as hoses, watering cans, road barriers, etc.
What is virgin vinyl?
This is the term used for vinyl product that does not contain recycled or reground products. Recycled products that may be imported into an extrusion plant may contain impurities or lower grade vinyl which can seriously affect the finished product's resilience, impact resistance and UV inhibition. Southwest Vinyl purchases from manufacturers who extrudewith virgin vinyl materials.
Can a vinyl fence break?
Southwest Vinyl High Density Polymer material has five times the tensile strength of wood and is four times more flexible. However, any material will break when enough force is applied. Southwest Vinyl fence profiles are formulated using only the highest quality impact modifiers in precisely engineered amounts to ensure the greatest impact resistance available. These profiles are engineered to withstand greater forces than the minimum required by ASTM.
Windload Calculations: Mathematical calculations that determine if a style of fence can withstand a particular wind velocity without failure. Kroy lifetime vinyl fences can be constructed to withstand 120+ MPH microbursts with optional metal internal post and rail reinforcements.
PVC or uPVC: Poly Vinyl Chloride. Can refer to the resin used in Vinyl production, or can refer to the finished product itself, including additives. High Density Vinyl Polymer is a highly advanced type of PVC, such as the types used in vehicles and body armor. The term uPVC refers to Ultra-Violet (UV) protected PVC. All PVC used in the manufacture of exterior products by reputable manufacturers is UV - inhibited, or, uPVC.
Vinyl: See PVC above
Resin: The base material used in the production of materials. For Vinyl fences, High Density Vinyl Polymer resin is used. There are several grades and several qualities of PVC Resin. For example, there is high-quality Siding Grade Resin, and low-quality Pipe Grade Resin. Different manufacturers have varying qualities and consistencies of resin.
TiO2: Titanium DiOxide. This is the most common ingredient used for Ultra Violet ray protection. TiO2 is a white pigment that reacts with Water and Oxygen. Water, or moisture in the air is necessary for this product to do its job effectively. There are at least 2 grades of TiO2: Uncoated, or Chalking Grade, and Coated, Durable or Non-Chalking Grade. The primary difference, apart from the higher cost of the non-chalking grade, is that it will chalk at a much slower rate, therefore providing a more lustrous finish for a longer period of time. It is interesting to note that many manufacturers suggest periodic watering of newly installed vinyl fences in desert climates for the first few months, as this will help strengthen molecular bonding of TiO2 and resins.
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