One of the oldest methods for making candles was the dipping method. The dipping method involves repeatedly dipping the wick into heated wax (liquid wax) or waxy substance until the waxy substance adheres and reaches the desired thickness.
The wick would have been made from dried rushes, while the waxy substance would have consisted of molten fat. Different types of material for wicks and wax are now available, and the method has been largely adapted to automated and electronically operated machinery.
Another method for creating candles is the pouring method. This can involve pouring melted wax over a suspended wick that is being simultaneously twirled (generally by hand), or pouring melted wax into a pre-heated, tube-shaped mould with the wick passing through. The wax is left to cool before removing. The wick is prepared prior to pouring and is pulled through a hole in the tip of the mould.
Modern technology allows for mass production as well as increased speed, accuracy, and quality, but some candle makers may still use traditional methods. They may manually dip, roll, and pour/mould the candles.
Candle making or manufacturing generally involves three main steps: making and preparing the wick, preparing the wax base, and then moulding or extrusion (http://www.madehow.com/Volume-1/Candle.html).
Wick Preparation
The wick plays a crucial role in delivering the fuel to the flame. It affects the burn time and efficiency of a lit candle. For this reason, the wick has been called the “soul” of the candle and is considered one of the most important components. In the manufacturing process, the preparation of the wick is usually the first step.
The number of threads, thickness, and material are all chosen based upon the shape, size, type of wax, and the production or chosen candle making method.
Candles made by stretching need a wick that can candle the pressure. Thicker candles may need larger wicks, while smaller candles may need thinner wicks. Wicks that are too thick or that draw too much fuel may cause the flame to flare and produce soot, while too little can cause the flame to sputter out.
The wick also affects and is reliant on the “fuel source” or wax. Some fuel sources, such as refined paraffin wax, soak more easily and thus easily travel up the wick and produce wax vapour. Thicker waxes, such as stearin and beeswax, may require a thicker wick for sufficient absorption. The melting point of the wax also changes the type of wick needed, since some waxes may require more heat.
The amount of wax consumed in grams per hour by the wick is known as the burn rate, and the amount of time it takes for the wax of the candle to be consumed completely is known as the burn time. The higher the burn rate, the more wax will be consumed per hour, and the lower the burn rate, the less wax will be consumed.
You can get an approximate burn rate of a candle by weighing the candle before and after burning, and then determining how much wax was consumed (how many ounces or grams were lost) in the amount of time that has past. You can then use this amount to determine the overall burn time of the candle.
Fragrances, colour, and other additives also influence the type of wick needed. Similar to the effect of different fuel sources, some fragrance ingredients easily travel up the wick, while others do not. They may also have different temperatures at which their vapour will combust, also known as “flash points.” Fragrances with lower flash points may need a thinner wick to prevent the flame from becoming too large and hot, while others may need a thicker wick for it to break down and vaporize. Extra oils or ingredients often require a larger wick in order to combust.
Types of colours, such as dye chips, colour blocks, liquids, and powders, and whether they are used in the wax or applied to the exterior, can also affect the composition of the wax, how it burns, and what type and size of wick is needed. Some pigments can clog the the candle wick and cause increased smoking. If you have a candle that is excessively sooting or flickering, and you are burning it properly, then it may be a sign that the wrong type of wick was used.
The wick can be made from a variety of material, including paper, flax, hemp, cotton, metal, and wood, with cotton and paper-cotton combinations being the most common in candles manufactured within North America.
There are hundreds of types of wicks that are braided, knitted, twisted, and more, but they can be categorized into four major types: flat wicks, square wicks, cored wicks, and specialty wicks.
Flat wicks usually consist of three bundles of fibre or thread that are flat-plaited or knitted. They provide a very consistent burn and curl in the flame. Curling in the flame is when the wick bends at a 90 degree angle, toward the exterior, keeping it in the outer mantle of the flame when the candle is lit. This causes the wick to be shortened naturally in a self-trimming effect. It also prevents mushrooming at the tip.
Mushrooming, also known as carbon heading, is the result of carbon buildup. It occurs when the wax burns faster than the wick and leaves a curled, blackened bit of excess wick. This black ball or clump of wick may eventually crumble down. Some mushrooming will always occur, but excessive amounts can prevent the candle from burning correctly and may cause smoking.
Square wicks are braided or knitted, and also curl in the flame. They are more rounded and more robust than a flat wick, and can help inhibit clogging. This type is popular for beeswax candles and plant waxes such as soy.
Cored wicks are braided or knitted and use a core material to keep the wick straight while burning. They have a round cross section. A variety of core materials, including cotton, paper, zinc, or tin, can be used for different stiffness effects. The rigidity makes them a popular choice for container candles and votives. It helps keep the wick upright when the wax liquefies.
Zinc core wicks, a common type of cored wick, is made with a cotton fibre braid surrounding a zinc core. They are the most rigid, followed by paper and cotton, and do not burn as hot as other wicks. They may need to be pre-waxed or made thicker when using with vegetable waxes.
Another type of core wick that can still be found is lead wicks. Lead wicks were banned in North America, but can still be found in imported candles. When these lead-core wicks are burned, they can release lead and other heavy metals into the air. These airborne heavy metals can reach levels that are much higher than acceptable limits and can pose a serious health threat.
Specialty wicks are designed for specific candle applications, such as if the candle will be used only in a specific environment, and particular burn characteristics are needed to achieve the desired effect or result. Examples are oil lamps, tea lights, and insect-repelling candles.
Wooden wicks may also be used, but they are not as common. They provide maximum rigidity and do not need trimming. Two main types are hard wood wicks and soft wood wicks. These wicks provides little carbon buildup and minimal smoking and create soft crackling and popping noises when burning. The amount of crackling directly relates to the type and amount of fragrance oil, colouring, and wax. The wood is usually treated with a burning agent to promote a consistent burn and continuous relighting. However, they can produce a large flame and should be used in containers, and not in pillars or votives.
Common types of wicks include HTP series wicks and CD wicks. The HTP (High Temperature Paper) consists of a specially constructed braid, with a flat-braided cotton fibre design with intertwined thin paper fibres. This provides a self-trimming affect and reduced carbon build up like the flat and square wicks, but with increased rigidity like a cored wick. They provide a hotter burn, which is suitable for use with waxes that have a higher melting point.
CD wicks (Heinz Stabilo wicks) are a coreless wick similar to the HTP series. They consist of a non-directional, flat braid style with special paper filament woven around, and are primed with a natural wax coating. They are a versatile wick that offers increased rigidity and promotes a consistent burn.
Other types of wicks include the ECO series, LX wick (German coreless), and the RRD series wicks. They differ in the unique construction of the braid and the type and treatment of the fibres used.
Round wicks, like the RRD series, have a tightly braided core designed with tension threads. They consist of a few threads that are interlaced asymmetrically to create a small artificial tension in the wick to provide a centred burn pool and allow the wick to lean over the exterior of the flame. This gives a slight curl when burning which helps create the self-trimming effect and provides a hotter burn. This tightly braided flame is considered “directional” because it has capillary action that flows better in one direction.
Braided, knitted, or plaited fibres encourage a slow, consistent burn, while twisted wicks burn much faster because of the loose construction, and are often used for birthday candles. Wicks made of natural hemp fibres burn hotter than cotton.
After the raw wick is chosen and prepared, it is treated or primed with chemicals, inorganic salt solutions, or a wax formula to help increase stiffness and promote consistent burning and easy lighting. This treatment helps eliminate air bubbles and helps provide the right amount of fuel to the flame so that it won’t burn too quickly and extinguish. The wick may be coated with a coating machine or can be done by hand by soaking or dipping the wick into the solution, and then pulling tight and leaving to dry.
Some wicks may also be tabbed, such as those used in votives, jars, and gels. A wick tab, also known as a sustainer tab, is a small, flat metal disc with a stem or raised “neck” in the centre (called the wick collar) with a hole in the middle for the wick. The tab is added to the end of the wick, where it is crimped in place. It helps hold the coated wick straight during the life of the candle and extinguishes the flame before it reaches the bottom of the candle; reducing the chance of the container getting too hot and transferring the heat to the surface below. This can be done with a wick tabbing machine, or can also be done by hand.
Extra long collared wick tabs may be needed for decorative candles that contain three-dimensional accessories.
Some candle makers or manufacturers may make their own wicks by selecting the fibres or material and then braiding, plaiting, knitting, or twisting it depending on the chosen material, and then coating and tabbing it, but wicks can also be purchased raw (plain or uncoated) or primed by the spool or yard, or pre-tabbed in various sizes.
The wick plays a significant role in the proper burning of the candle, and it important that you seek out a well-made candle or pay careful attention to the wick you choose when making your own candle.
In the next blog, we will look into another vital component in the candle making process: the preparation of the wax base.
Leave a Reply
You must be logged in to post a comment.