duct tape

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Background

Duct tape is a cloth tape coated with a poly-ethylene resin on one side and very sticky rubber-based adhesive on the other. Unlike other tapes, the fabric backing gives duct tape strength yet allows it to be easily torn. Duct tape is also very malleable and can adhere to a wide variety of surfaces. While it was primarily designed for use in air ducts and similar applications, consumers have found a broad range of uses for this popular product. It can be used for a number of household repair jobs, as a fastener instead of screws or nails, and in car maintenance. Snowmobilers have even been known to apply duct tape to their noses to thwart frost-bite and sunburn. The product has generated so much interest, that there are books and web sites dedicated to its unconventional, and often comical, uses. For example, The Duct Tape Book describes how to use duct tape to make aprons and trampoline covers.

History

There are conflicting accounts concerning the history of duct tape. According to Manco, Inc. (maker of DuckTm Brand tape), it was created by Permacell—a division of Johnson and Johnson—during World War II in the 1940s. Other experts claim that the tape product was invented in the 1920s by researchers for the 3M Company, led by Richard Drew. Most accounts agree, however, that Permacell perfected duct tape during the war. Using state of the art technology, their research team developed a process to combine multiple layers of adhesive onto a polyethylene coated cloth backing. Some say this early product was nicknamed "duck tape" because it repelled water like the bird's feathers or because the fabric mesh was made from duck cloth.

Regardless of its origin, the military found many uses for duct tape. One of its earliest applications was to hold ammunition boxes together. For this reason, soldiers referred to it as "gun tape." The Air Force found other uses for the product and duct tape was used to cover gun ports on planes to cut down the air friction during take off. Like many other military products, duct tape was originally colored olive green, but after the war it was changed to the more familiar silver color. Manufacturers began marketing it to household consumers who found a variety of new uses. The tape is easier to use and just as effective as screws and bolts when it comes to holding together the kind of ductwork that is found in new homes with forced-air heating.

As the consumer demand grew, marketers began packaging their tapes in a more consumer-friendly fashion. According to Manco, they were the first company to shrink-wrap and label the duct tape so that it could be easily stacked on display shelves. This packaging improvement made it easier for shoppers to distinguish between the different grades. By 1999, Manco was selling approximately 5,900 short tons (5,352 metric tons), or 246,217 mi (396,240 km), of tape each year.

Design

Duct tape is designed for different application based on its grade. The grade is determined by the combination of adhesive type and the strength of the backing material. The strength of the cloth fabric depends on the number of threads it contains; this number determines the rip strength of the cloth. For example, military grade tape has a 40-lb (18-kg) rip strength while the strength of less expensive tapes is in the 20-lb (9-kg) range. Tape designed for use by the federal government must comply with a lengthy 12-page specification guide that dictates the strength and other factors. Commercial grades are less demanding and are typically classified as either utility, general purpose, or premium grade. Other speciality grades include "nuclear tape," which is used in reactors and a "200-mi (322-km) an hour" tape specifically designed for race cars.

Raw Materials

Cotton mesh

Cotton mesh forms the backbone of duct tape. It provides tensile strength and allows the tape to be tom in both directions. Cloth that has a tighter weave and higher thread count is of a higher quality, provides greater strength, and gives a cleaner tear. A premium quality tape can have a thread count of 44 x 28 threads per square inch. Accordingly, tape made with this fabric is more expensive. The cotton fabric is called a "web" when it is spread across the coating machinery.

Polyethylene coating

The cotton fabric is coated with polyethylene, a plastic material that protects it from moisture and abrasion. This plastic coating is flexible and allows the tape to adhere better to irregular surfaces. The polyethylene is melted and applied to the fabric in a preliminary coating operation. The coated fabric is then stored on rolls until the manufacturer is ready to apply the adhesive.

Adhesive compound

The adhesive used in duct tape is unique for two reasons. First, the adhesive itself is formulated with rubber compounds that ensure long-term bonding. Other tapes typically use adhesive polymers that are not as binding. Second, the adhesive is applied to the substrate in a much thicker coating than those used on cellophane or masking tapes. This too serves to increase the adhesive properties of the tape.

The Manufacturing Process

Adhesive compounding

• The rubber-based adhesive used in duct tape is prepared in a multi-step process. In the first step the adhesive is compounded in a mixer known as a Branbury-type mixer consisting of a stainless steel tank equipped with a steam jacket to heat the compound and a high torque mixer. The rubber compounds are introduced in pellet form, then heated and mixed until they are melted and homogenous. Other ingredients are added to the blend tank as specified in the formulation. These include tackifying agents, viscosity modifiers, antioxidants, and other adjuncts. The final mixture is thick but smooth enough to be pumped to a holding tank connected to the coating equipment.

Adhesive application

• The adhesive and the fabric are combined using sophisticated coating equipment. First, the adhesive is further softened by heat on a roller mill. A roller mill consists of closely spaced hollow rollers which are made of heavy gauge stainless steel. The rollers are attached to high torque gears and a motor that rotates the them at a set speed. The temperature of the rollers is controlled by continuously pumping water through them. The top roller is held at a temperature of 260°F (127°C) and the center roller is kept at 100°F (38°C). The cylinders are fixed in place so that only a small gap exists between them. As the rollers tum, the rubber compound is fed into this space. The friction generated heats and softens the rubber. This arrangement allows the molten adhesive to form a thin sheet across the surface of the rollers.
• The cloth is then fed into the coating machine through another set of rollers. It runs against the third roller (held at 199°F [93°C]) that is in contact with the adhesive. During this process, known as coating, the adhesive is transferred to the cloth. By controlling the gaps between the rollers, the machine operator can determine how much adhesive is applied to the cloth. When the adhesive is ready, the cloth backing material—which has been pre-treated with polyethylene—is fed off its storage roll and onto the coating rollers. As the backing material comes in contact with the third roller, it picks some adhesive up off the transfer roller. This process used to apply such heavy adhesives is known as calendaring. Coatings as thin as 0.002 in (0.05 mm) can be used but they become less uniform below 0.004 in (0.Imm). These fluctuations occur because the rollers experience a small degree of bending as they rotate. This creates uneven gaps between the rollers which cause variations in coating weight across the web.
• After coating, the tape fabric is wound onto large cardboard cores. When enough tape has been coated and the roll is full, it is removed from its spindle and moved to another area where it can be cut to the proper size. These storage rolls are approximately 5 ft wide and 3 ft in diameter (152 cm x 91 cm).

Respooling and slitting

• After the coating process is complete, the roles can be cut to their final size. This is done by "unspooling," or unwinding, the large rolls onto a machine equipped with a series of knives. The knives cut the web into more narrow segments which are then rewound on smaller cardboard cores. This process is known as "slitting."

Packaging operations

• 6 In this final stage the rolls of duct tape are packaged for sale. They are typically shrink wrapped, either singularly or in packages of two or three. These packages are then boxed and marketed for shipping.

  Depending on the manufacturer, the steps described above can be combined through automation into fewer steps. For example, Permacell uses a self-contained apparatus which mixes, heats, and fastens the adhesive onto the backing. This method allows the glue to be prepared without pollution-causing solvents.

Quality Control

Duct tape must meet a series of standard tests described by the American Society for Testing and Materials. These methods measure two key properties of the adhesive: its adhesive strength (which determines how well the tape will adhere to another surface) and cohesive strength (which shows how well the adhesive will stick to the cloth backing). One common method of evaluating these properties involves applying the tape to a standardized stainless steel plate, and then measuring the force required to rip it off. The plate is then examined to determine how much, if any, of the adhesive residue is left behind. The adhesive coating itself is monitored to evaluate how well it sticks to its backing. Conditions where the adhesive leaves a residue is known as creeping, crazing, oozing and bleeding. Quality control technicians also watch for fisheyes, the term used to describe an uneven application of adhesive.

In addition to the standard tests, each manufacturer has their own proprietary methods for evaluating their products. For example, companies may measure the duct tape's breaking point. Others evaluate the "scrunch" sound of the tape as it unwinds because consumers believe a noisy rip off the roll is a sign of strength. Other tests are designed to measure quick stick. One way this is done is by shooting ping-pong balls at tape strips with the sticky side up to measure how far they roll before they are stopped by the tape.

Despite duct tape's reputation for superior adhesion, testing done by independent researchers has found that the tape does not work as well as it is intended to. In 1998, researchers Max Sherman and lain Walker of the Department of Energy's Lawrence Berkeley National Laboratory evaluated 12 different kinds of duct tape. They designed an accelerated aging test that mimicked the temperature conditions of a home or office building from night to day and winter to summer. They used a series of standard finger joints which connected a smaller duct to a larger one. Wrapping each test connection with a different brand of duct tape, they evaluated the seal under temperature and humidity conditions designed to be similar to those found in home heating and air conditioning systems. The researchers also performed a bake test in which the sample joints were baked at higher temperatures. Most of the joints tested were found to be leaking by 50% or more, according to the researchers. Their test results also showed that a large proportion of the tapes failed to function when temperatures dropped below freezing (32°F [0°C]) or rose over 200°F (93°C). However, the tape industry disputed these findings, claiming that for optimal efficiency their tape products should be assisted by collars or clamps.

The Future

Environmental and price considerations drive researches to identify new adhesive formulations at a lower cost—general price for one 2 in (5 cm) wide, 50 yd (46 m) roll of all-purpose duct tape is about three dollars—that maintain high functionality with-out being damaging to the environment. In addition, marketing considerations drive product improvements. In response to criticism that duct tape does not function well at extreme temperatures, manufacturers are creating more advanced formulations specially designed to withstand severe heat and cold fluctuations. For the first time, formal standards are being created specifically for duct tape to be used on flexible duct work. Tape manufacturers support this plan because they believe that certification by Underwriters Laboratories (a product safety testing organization) will boost their sales.

Where to Learn More

Books

Berg, Jim, and Tim Nyberg. The Duct Tape Book. Duluth, MN: Pfeifer-Hamilton Publishers, 1995.

Satas, Dontas. Handbook of Pressure Sensitive Adhesives. Second edition. Van Nostrand Reinhold, 1989.

Periodicals

Baird, Christine V. "U.S. Duct Tape Sales at $75 Million a Year and Growing." Knight-RidderlTribune Business News (October 21, 1996): 1021B0195.

"Duct Tapes Flunk Berkeley Lab Tests." Air Conditioning, Heating & Refrigeration News 204, no.18 (August 31, 1998): 1.

Harder, Nick. "Bring On the Duct Tape to Show Creativity." Knight-RidderlTribune News Service (April 15, 1999): K0467.

Turpin, Joanna R. "Duct Tape: The Ultimate Tool." Air Conditioning, Heating & Refrigeration News 201, no. 16 (August 18, 1997): 9.

Other

Underwriters Laboratories Inc. http://www.ul.com (January 2001).

[Article by: Randy Schueller]

• Adhesives and Binders - duct tape: wide, silver-gray, strong adhesive tape, used for Sheetrock work, household repairs, etc.

A roll of glossy, gray duct tape.

Duct tape, or duck tape, is cloth- or scrim-backed pressure sensitive tape often sealed with polyethylene. It is very similar to gaffer tape but differs in that gaffer tape was designed to be cleanly removed, while duct tape was not. It has a standard width of 1+⁷⁄₈ inches (48 mm) and is generally silver or black but also available in other colors. Revolite, formerly a division of Johnson & Johnson, originally developed duct tape in 1942 during World War II as a rubber-based adhesive tape with a durable fabric backing that resisted water^{[citation needed]} for use as sealing tape on ammunition cases.^[1] Because of these properties, it was also used to repair military equipment quickly, including jeeps, firearms, and aircraft.

Contents 1 Common uses 1.1 Usage in spaceflight 1.2 Usage on ductwork 1.3 Usage in Military 2 Alternative uses 2.1 In popular culture 3 Etymology 4 Different meaning in Australia and New Zealand 5 See also 6 References 7 External links

Common uses

Duct tape is commonly used in situations that requires a strong, flexible, very sticky tape. Some have a long-lasting adhesive and resistance to weathering.

A more specialized product, commonly known as gaffer tape, is preferred by gaffers, as it does not leave a sticky residue when removed. It comes in matte black, and is more easily torn into thin strips for precise application.

Duct tape, in its guise as "racer's tape", has been used in motorsports for more than 40 years to repair fiberglass bodywork. Racer's tape comes in a wide range of colors to help match it to common paint colors.^[2] In the UK, it is usually referred to as "tank tape" in motorsports use.^[3]

Duct tape is not intended to be used for sealing ductwork. Building codes usually require a special fire resistant product, often with a foil backing and long lasting adhesive.

Usage in spaceflight

Improvised wheel fender extension via duct tape, Apollo 17.

NASA engineers and astronauts have used duct tape in the course of their work, including in some emergency situations. One such usage occurred in 1970, when the square carbon dioxide filters from Apollo 13's failed command module had to be modified to fit round receptacles in the lunar module, which was being used as a lifeboat after an explosion en route to the moon. A workaround used duct tape and other items on board Apollo 13, with the ground crew relaying instructions to the flight crew. The lunar module's CO₂ scrubbers started working again, saving the lives of the three astronauts on board.

Ed Smylie, who designed the scrubber modification in just two days, said later that he knew the problem was solvable when it was confirmed that duct tape was on the spacecraft: "I felt like we were home free", he said in 2005. "One thing a Southern boy will never say is, 'I don't think duct tape will fix it.'"^[4]

Duct tape was also used aboard Apollo 17 to improvise a repair to a damaged fender on the lunar rover, preventing possible damage from the roostertails of lunar dust as they drove.^[5]

Usage on ductwork

To provide lab data about which sealants and tapes last, and which are likely to fail, research was conducted at Lawrence Berkeley National Laboratory Environmental Energy Technologies Division. Their major conclusion was that one should not use duct tape to seal ducts (specialty tapes are available for this purpose). (They defined duct tape as any fabric-based tape with rubber adhesive.) The testing done shows that under challenging but realistic conditions, duct tapes become brittle and may fail.^[6] Commonly duct tape carries no safety certifications such as UL or Proposition 65, which means the tape may burn violently, producing toxic smoke; it may cause ingestion and contact toxicity; it can have irregular mechanical strength; and its adhesive may have low life expectancy. Its use in ducts has been prohibited by the state of California^[7] and by building codes in most other places in the U.S. However, metalized and aluminum tapes used by professionals are still often called "duck/duct tapes".

Usage in Military

In military circles, there is a variant known as "shooters tape", typically olive-green, known for its resistance to oils and greases.^{[citation needed]} In the US Submarine fleet, it is called "EB Green," as the duct tape used by Electric Boat was green.^[8] It is also called "duck tape", "riggers' tape", "hurricane tape", or "100-mph tape"^[9][10]—a name that comes from the use of a specific variety of duct tape that was supposed to hold up to 100 miles per hour (160 km/h; 87 kn) winds. The tape is named so because it was used during the Vietnam War to repair helicopter rotor blades, thus earning the name 100-MPH tape.^[11] Duct tape was also used during the Vietnam War to balance helicopter rotor blades.^[12]

Alternative uses

Christmas light-impregnated duct tape space suit costumes used by Chicago based rock band Ophur. Model ship made with unusual materials: rolled-up tubes of paper, Express Mail labels, and duct tape. During the week prior to the traditional USC-UCLA rivalry American football game, the Tommy Trojan statue is covered in duct tape to prevent the spray-painting of rival UCLA's colors on the statue.[13][not in citation given]

Duct tape's widespread popularity and multitude of uses has earned it a strong place in popular culture, and has inspired a vast number of creative and imaginative applications.

Duck Products, the manufacturer of Duck brand duct tape, annually sponsors a competition that offers a college scholarship to the person who creates the most stylish prom formal wear made from Duck Tape.

A medical study by Adam Doorn announced on major news networks on October 15, 2002, stated that application of duct tape can be used as an effective treatment for warts.^[14] This treatment is often called by the name duck or duct tape occlusion therapy. A more recent study claimed to have cast doubt these findings, pointing out the original researchers didn't actually examine participants to determine if the warts were in fact gone, but instead phoned participants and asked.^[15] In the 2006 study of 103 children [Haen et al.], duct tape did not perform significantly better than a placebo. This study compared clear duct tape, applied six nights a week to corn pad placebos, which were applied one night a week. In a study released in 2007, a study among older adults found duct tape helped only 21% of the time and was no better than moleskin, a cotton-tape bandage used to protect the skin. However, researchers used transparent duct tape that unlike the grey duct tape does not contain rubber. "Whether or not the standard type of duct tape is effective is up in the air," said Dr. Rachel Wenner of the University of Minnesota, who started the new study as a medical student. "Theoretically, the rubber adhesive could somehow stimulate the immune system or irritate the skin in a different manner."^[16] The Wenner study was published in the March 2007 issue of Archives of Dermatology.

As a quick fix, duct tape can be used as a temporary bandage, until proper medical treatment and bandages can be applied to a wound.^[17]

Recently, duct tape has proven the most effective fix to Apple's iPhone 4 dropped call issue, even over Apple's own rubber case.^[18]

In popular culture

The Duct Tape Guys (Jim Berg and Tim Nyberg) as of 2005 have written seven books about duct tape. Their bestselling books have sold over 1.5 million copies and feature real and unusual uses of duct tape. In 1994 they coined the phrase "it ain't broke, it just lacks duct tape". Added to that phrase in 1995 with the publication of their WD-40 book was, "Two rules get you through life: If it's stuck and it's not supposed to be, WD-40 it. If it's not stuck and it's supposed to be, duct tape it". Their website features thousands of duct tape uses from people around the world ranging from fashions to auto repair. The combination of WD-40 and duct tape is sometimes referred to as "the redneck repair kit".

The Canadian sitcom The Red Green Show's title character often used duct tape (which he dubbed "the handyman's secret weapon") as both a shortcut to proper fastening as well as for unconventional uses. The series sometimes showcased fan duct tape creations. The series had a feature film based on it entitled Duct Tape Forever and several VHS/DVD compilations of the show's use of the tape have been released. Since 2000, series star Steve Smith (as Red Green) has been the "Ambassador of Scotch Duct Tape" for 3M.^[19]

The Discovery Channel series MythBusters has featured duct tape in a number of myths that involve non-traditional uses. Confirmed myths include suspending a car for a period of time, building a functional cannon, building a two-person sailboat, and constructing a bridge that spanned the width of a dry dock. In the episode "Duct Tape Plane", the MythBusters repaired (and eventually replaced) the canopy of a lightweight airplane with duct tape and flew it a few meters above a runway.

Etymology

The origin of the name of the product, "duck tape" or "duct tape", is the subject of some disagreement.

One view is that it was called "duck tape" by WWII soldiers either because it resembled strips of cotton duck (canvas) or because the waterproof quality of the tape contributed to the name, by analogy to the water-shedding quality of a duck's plumage. Under this view, soldiers returning home from the war found uses for duck tape around the house where ductwork needed sealing. Other proponents of this view point to older references to non-adhesive cotton duck tape used in Venetian blinds, suggesting that the name was carried over to the adhesive product. The Oxford English Dictionary says that perhaps "duct tape" was originally "duck tape". This view is summarized most notably in a New York Times article by etymologist William Safire in March 2003. Safire cites use of the term "cotton duck tape" in a 1945 advertisement for surplus government property.^[20] The Brooklyn Daily Eagle uses the term "duck" in 1902 quotation for "100,000 yards of cotton duck tape" being used to protect the cables of the Brooklyn Bridge.^[21] Thus a fabric duck tape was available to which an adhesive could have been added.

Different meaning in Australia and New Zealand

Australian "duct tape".

The term duct tape can lead to confusion between people more familiar with the North American usage of the term and those from regions such as Australia and New Zealand, where a different type of tape is often sold as duct tape: a PVC tape without a fabric backing.^{[citation needed]}

See also

• Duck Products
• Duct tape alert
• Speed tape
• Duct tape occlusion therapy

References

1. ^ "Genericide: When a Brand Name Becomes Generic". Age of Persuasion. CBC. http://www.cbc.ca/ageofpersuasion/episode/season-5/2011/05/06/season-five-genericide-when-a-brand-name-becomes-generic-1/. Retrieved 14 May 2011. 
2. ^ Racers Tape Products
3. ^ Demon Tweeks website
4. ^ Associated Press article, referring to the use of duct tape on Apollo 13.
5. ^ "Lunar Dust and Duct Tape". Apod.nasa.gov. http://apod.nasa.gov/apod/ap040417.html. Retrieved 2009-07-21. 
6. ^ "Sealing HVAC Ducts: Use Anything But Duct Tape". Lawrence Berkeley National Lab Energy Performance of Buildings Group. 1998-08-17. http://www.lbl.gov/Science-Articles/Archive/duct-tape-HVAC.html. 
7. ^ "California Energy Commission Title 24 of the Building Energy Efficiency Standards". Energy.ca.gov. http://www.energy.ca.gov/title24/changeout/. Retrieved 2009-07-21. ^{[dead link]}
8. ^ "The EB-Green myth - Topic". community.discovery.com. 2011 [last update]. http://community.discovery.com/eve/forums?a=tpc&s=6941912904&f=9741919888&m=55619699301&r=15719659801#15719659801. Retrieved 30 June 2011. 
9. ^ Airlift Technologies supplier of tape under this name
10. ^ The Medical NBC Battlebook USACHPPM Tech Guide 244 (May 2000) p 1.13
11. ^ Vietnam Stories, Army Times (September 1993)
12. ^ Richard T. Edwards (June 5, 2011). "Vietnam -- Balancing Rotorblades With Duct Tape". 4th Battalion, 77th Field Artillery AFA [blog]. http://4thbattalion77thfieldartilleryafa.blogspot.com/2011/06/vietnam-balancing-rotorblades-with-duct.html. 
13. ^ Rajan Menghani, Pranks of the past, present, The Daily Bruin, December 01, 2005.
14. ^ "AAFP tips page". Aafp.org. 2003-02-01. http://www.aafp.org/afp/20030201/tips/8.html. Retrieved 2009-07-21. ^{[dead link]}
15. ^ "Efficacy of Duct Tape vs Placebo in the Treatment of Verruca Vulgaris (Warts) in Primary School Children". Archpedi.ama-assn.org. 2006-11-01. doi:10.1001/archpedi.160.11.1121. http://archpedi.ama-assn.org/cgi/content/abstract/160/11/1121. Retrieved 2009-07-21. 
16. ^ "Study: Duct tape wart cure overstated". Usatoday.Com. 2007-03-19. http://www.usatoday.com/news/health/2007-03-19-duct-tape_N.htm. Retrieved 2009-07-21. 
17. ^ "archive of defunct About.com Frugal Living Page on Duct Tape". Web.archive.org. 2006-04-29. Archived from the original on 2006-04-29. http://web.archive.org/web/20060429023929/http://frugalliving.about.com/cs/tips/a/ducttape_2.htm. Retrieved 2009-07-21. 
18. ^ "iPhone duct tape fix". cnn.com. 2010-07-13. http://www.cnn.com/2010/TECH/mobile/07/13/iphone.4.duct.tape/index.html?hpt=C1. Retrieved 2010-07-13. 
19. ^ 3M Canada Press Box
20. ^ "The Way We Live Now: On Language; Why A Duck", New York Times, March 2, 2003. Retrieved April 17, 2008.
21. ^ "Brooklyn Daily Eagle". http://eagle.brooklynpubliclibrary.org/Default/Scripting/ArchiveView.asp?skin=BEagle&AppName=2&GZ=T&BaseHref=BEG%2F1902%2F11%2F21&PageSize=3&enter=true&Page=15.  21 Nov 1902 "Considering..that 100,000 yards of cotton duck tape must be wrapped around the cable with neatness and exactitude, it may be imagined that this method of cable preservation is quite expensive."

External links

• Etymology provided by Jan Freeman, Boston Globe (reproduced)
• Duct Sealant Longevity
• Duct tape not good for ducts from the California Energy Commission
• http://www.octanecreative.com/ducttape/duckvsduct.html

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