How to Select and Use Kevlar Fire Wicks

Kevlar wicking for fire props

Below, we describe wick characteristics and some of the differences between the various brands.

• The weave of the tape depends on the thickness, with twill being the best weave (see photo right, last two wicks on the right). If a strand burns or breaks due to abrasion, the fabric will not come apart. In contrast, if one or two strands break in a cross-weave (see photo right first wick on the left), the others will come apart as well. One should note that a twill weave is often not used in making 1/16-inch-thick material. It is better to use half as much 1/8-inch wicking, than twice as much of the 1/16-inch if it is made with a simple cross weave.
• The thread used to make the tape varies. There are many types of thread used to make kevlar wick. In the photo below is shown four types of thread that are typical for making wick. The top is fine pure Kevlar twisted pair, the second down thicker pure kevlar tiwsted pair, then spun pure Kevlar and bottom fiber core spun Kevlar. The kind of thread effects the density of the wick, abrasion resistance and how much fuel the wick will hold.
• The fiber core Kevlar thread wicking has a very tiny fiberglass core around which the Kevlar yarn is spun. This allows the thread to be more fluffy, but not break while is being woven on the machine. The more fluffy the thread is the more fuel it will hold. However the more fluffy it is the less abrasion-resistant it is. You can see from the photo that the thread has a wide range of thickness and texture, which is why kevlar wicking can vary widely on how it looks and performs. Each kind of kevlar webbing is defined by the thread type and weave type. You can see in the photo below how much of a difference there is between the threads, and how the spun thread has a much bigger diameter than the un-spun thread.
• Low-quality wicking has fiberglass (much cheaper and heavier material than Kevlar) blended into the yarn before the thread is made. When woven into wicking, the result is a much denser thread and a higher total weight. Furthermore, these fiberglass fibers cannot hold as much fuel as Kevlar ones. Often cheap wicking uses a low-quality cross-weave pattern, which allows it to be manufactured faster.
• Given that Kevlar is a brand name, cheaper wick manufacturers may use an aramid fiber that resembles Kevlar. If the wicking material fibers are made in China, they could have a lower heat-resistance than higher-quality brand name fibers. In making wicking material, the Kevlar thread accounts for about 60% of the cost. Since all weaving equipment worldwide is automated, the only way to make lower-cost wicking is to use inferior raw materials. There are other brands of aramid thread that has the same physical properties of Kevlar thread, most (if not all) Kevlar wicking is not made from Kevlar brand material as it is way overpriced.
• Technora is another brand of aramid fiber that has a much higher temperature rating of around 900F compared to 500F for Kevlar. Currently, Technora comes only in a rope form. It does not have good fuel absorption properties so it is used primarily as a leash material rather than wicking. All Technora products sold are made for the rope industry. Technora fibers have not yet been used for custom-made wicks implemented specifically in fire dance props.
• Renegades Kevlar-based rope is made in two ways. The first type has an outer woven sleeve and linear strands of Kevlar wool that fill the sleeve or tube (see image below left). This construction allows the rope to hold a large quantity of fuel, but it is not strong enough to lift loads. Accordingly, it is meant to be used solely as a wick and not for load-bearing purposes. One can also utilize it as an insulation gasket. The second type of rope is a 12-strand woven rope that has continuous strands but no core (see image below right). This makes for a very strong rope but it does not hold as much fuel as linear core. As a result, this type of rope is better suited as leash material or for making props that have very high levels of abrasion.

Kevlar, Nomex, Technora, Twaron, and Abseil

These are some of the common brand names of heat resistant products, it could be rope, tape, webbing, cloth, firefighter gear etc. Each of these branded products has different characteristics depending on what type of fiber is used to make the thread and in turn the wick. For fire wicking the most important factor is heat resistance. Technora is has the highest 900F, Kevlar 500F and Nomex 300F. This is a approximate heat resistance as each of these brand names have different ratings, as they use different chemicals to make the fibers.

This has lead to lots of confusion in the fire dance or flow arts field, as people refer to the brand and not the fiber it is made from. In addition many manufactures do not use brand name fibers to make the products. For example virtually no manufacture of fire wicking, which we call Kevlar wick, actually used DuPont Kevlar, they use a cheaper generic non-branded aramid fiber and we call it Kevlar. Just like Kleenex it is a common name/brand. (Technora) poly-paraphenylene terephthalamide (PPTA), (Kevlar) poly-para-phenylene terephthalamide, (Nomex) poly-m-phenylenediamine isophthalamide are all are pretty complicated fiber names so it is no wonder why people use brand names. The term often used for all these types fibers is aramid. Which simply means, a man made organic polymer produced by spinning fiber from a liquid chemical blend... Pretty vague at best. When you buy wicking by name is really does not mean much you have too test it and see how good it really is.

But that issue aside, the main problem with using any of these aramid fibers to make fire wick is the heat generated while using the prop is way above the rating of the material. So all of these burn up, it is just a matter of how fast. Using higher temperature materials that can with stand the heat, like fiberglass or ceramic, do not have good properties, in regards to wicking weight, holding fuel or abrasion resistance. So fire performers are using a inferior material, the best option available, made out of somekind of aramid fiber.

Kevlar wick fuels

The type of fuel used has a large influence on the life span of the wick. With many kinds of fuel available, the most common ones fall into two basic categories.

• Kerosene is the primary component in lamp oil, tiki torch fuel, barbecue lighter fluid and airplane fuel. The advantage of a kerosene-based fuel is that it burns slower and at a lower temperature than Coleman white gas. It is not highly flammable and will not easily catch fire if spilled. However, it is harder to ignite at the start. The flame is more orange in color than a white gas flame and not as bright. Compared to white gas, this type of fuel will at least double the life span of the wicking material. It should be noted that cheaper kerosene-based products contain more impurities. The only pure kerosene product is airplane fuel. All of these kerosene fuels are toxic and must not be put in your mouth.
• White gas or Coleman camp stove fuel is very flammable and the prop can be easily ignited. It has a bright yellow flame. This high-burn temperature reduces the life span of the wicking material, and if spilled the fuel will instantly catch on fire. White gas in a vapor form is extremely dangerous and explosive. In the early 1980s to 1990s and before the invention of small propane cooking devices, it was a very common and cheap camping stove fuel, and thus became prevalent in the juggling scene. Over time, this fuel choice was passed along by word of mouth from jugglers to fire dancers. Although white gas does produce less smoke, it has more disadvantages than advantages when compared to kerosene fuels. Some performers add approx. 5% Coleman white gas to the kerosene fuels to make them ignite faster; the white gas burns off quickly and then the wick’s flame is fueled just by kerosene.

Kevlar wick fueling and Kevlar wick construction.

Fire props are made of some combination of flat wick tape or rope rolled/tied/woven around a core. Important factors to be considered when fueling and using the wick are as follows:

• The best way to fuel a wick head is to squirt on the fuel using a barbecue lighter fluid-type bottle. In the early 1980s to 1990s, it was common to dunk a juggling torch into a wide-mouth bottle and then shake out the excess fuel before use. This is wasteful and ecologically unsound. It is much better to apply the correct amount of fuel on the wick with a squirt bottle.
• For many uses, fire wick is wrapped around a shaft or some other inner support. It is very important that the Kevlar material is not too thick, otherwise it will burn on the inside of the wick head instead of the outside. Stopping combustion in the center is extremely difficult, even after the fuel is gone. This is why all monkey fist wick heads have a wood or tin foil ball in the middle. The wick should not be more than 2 inches thick to prevent internal combustion.
• Kevlar wicking is not sufficiently resistant to high temperatures to last forever. However, you can greatly increase the life span of the wick if you put it out while there is still fuel burning in the wicking material. As the prop burns down, you should smother the flame out ( do not try and blow or spin it out). Even if all the fuel is burned, the wick ends are still hot and the wicking material will continue to burn. After each use, allow the wicks to cool off. To obtain the longest life span, allow for sufficient cooling time between each use.
• When making a wick head, one often needs to sew the outside edge of the wick. This should be done using Kevlar thread or twisted cord, which comes in several thicknesses, with thicker being better. Do not use a running stitch. Knot off each stitch so if it was to burn through, all the stitching will not unravel. Wire, ideally foundation wire, is sometimes used to tie the wick to the prop. The problem with using wire is that it will get very hot and burn you on contact. Generally,contact with a burning wick that contains no metal will not cause a burn injury, or at least it will be much less than if metal wire or hardware are present.

Kevlar wick fueling and Kevlar wick construction.

Fire props are made of some combination of flat wick tape or rope rolled/tied/woven around a core. Important factors to be considered when fueling and using the wick are as follows:

• The best way to fuel a wick head is to squirt on the fuel using a barbecue lighter fluid-type bottle. In the early 1980s to 1990s, it was common to dunk a juggling torch into a wide-mouth bottle and then shake out the excess fuel before use. This is wasteful and ecologically unsound. It is much better to apply the correct amount of fuel on the wick with a squirt bottle.
• For many uses, fire wick is wrapped around a shaft or some other inner support. It is very important that the Kevlar material is not too thick, otherwise it will burn on the inside of the wick head instead of the outside. Stopping combustion in the center is extremely difficult, even after the fuel is gone. This is why all monkey fist wick heads have a wood or tin foil ball in the middle. The wick should not be more than 2 inches thick to prevent internal combustion.
• Kevlar wicking is sufficiently resistant to high temperatures to last forever. However, you can greatly increase the life span of the wick if you put it out while there is still fuel burning in the wicking material. As the prop burns down, you should smother the flame out ( do not try and blow or spin it out). Even if all the fuel is burned, the wick ends are still hot and the wicking material will continue to burn. After each use, allow the wicks to cool off. To obtain the longest life span, allow for sufficient cooling time between each use.
• When making a wick head, one often needs to sew the outside edge of the wick. This should be done using Kevlar thread or twisted cord, which comes in several thicknesses, with thicker being better. Do not use a running stitch. Knot off each stitch so if it was to burn through, all the stitching will not unravel. Wire, ideally foundation wire, is sometimes used to tie the wick to the prop. The problem with using wire is that it will get very hot and burn you on contact. Generally,contact with a burning wick that contains no metal will not cause a burn injury, or at least it will be much less than if metal wire or hardware are present.