Duct tape is a widely loved one-stop solution that can be used for many different indoor and outdoor projects. However, duct tape isn’t without its downfalls, and for specific projects involving extreme temperatures, it may not be advised.

Duct tape as a whole is not flammable, but the mesh fabric used on the inside is. Made primarily of cotton, this portion is flammable until it’s coated with polyethylene, a product that causes it not to catch fire. The rubber adhesive that makes up the bonding agent is also not flammable, either.

Even though duct tape is not flammable, you may still be wondering about its durability in extreme heat. So, in the rest of this article, I’ll discuss how duct tape reacts in hot temperatures and the steps to take in your projects that deal with heat.

Duct Tape Isn’t Flammable, but It Can Melt

Although duct tape is heat resistant and not flammable, it can still melt.

In temperatures above what’s recommended, duct tape will begin to soften as the bonding adhesive fails. Furthermore, both the rubber and mesh material will begin to melt as the material disintegrates.

This failure can happen very rapidly if there’s prolonged exposure to extreme heat. Even though it won’t catch on fire, the material will warp and shrivel until it fully melts. 

Melted duct tape is no joy to deal with. Although it’s technically not flammable, you should still stay away from using it in high-temperature environments to avoid having to clean up the mess.

Still unsure about when and where to use duct tape? Let’s take a closer look at the recommended temperatures and the effects of using duct tape in the cold.

What Temperatures Is Duct Tape Safe to Use In?

Duct tape has a unique formula that makes it resistant to heat. Most types are composed of two sides:

  • Rubber or fabric on the outside
  • A bonding adhesive on the inside

The combination of the rubber side with the polyethylene-coated mesh fabric makes duct tape incredibly strong. It’s very durable and should last a long time, even in hot temperatures.

Still, if you’re working on a project that involves high or low temperatures, it’s essential to know if the tape you’re using is safe.

Duct tape is safe for use in temperatures between 20°F and 200°F. Temperatures outside of this range will likely affect the durability of the tape, such as damaging the bonding adhesive. That may lead to the tape having difficulty sticking.

Keep in mind that at either end of the heat spectrum, you may need to change the tape numerous times to keep it working.

Industry standards require that duct tape be heat resistant. So, although the bonding adhesive doesn’t stick as well on hot items (or very cold items), it will fail long before the duct tape melts. Even though it’s not flammable, it will be useless if used in temperatures that are too high.

Duct Tape in Cold Temperatures

As I mentioned before, duct tape won’t work as effectively in colder temperatures.

Although the recommended temperature stops at 20°F, duct tape will actually work in below-freezing temperatures.

There have been experiments that determined duct tape will continue to do its job under 140°F. Below this temperature, however, the bonding adhesive will begin to fail until the duct tape completely falls off.

Duct Tape Failure Timeline

Multiple tests were conducted on the time it takes different kinds of tapes and sealants to fail after they have been placed. The tape or sealant was exposed to various conditions, and the average effective lifetime was recorded.

The types of tape and sealants tested included:

  • Duct tape
  • Foil-backed butyl tape
  • Aerosol sealant
  • Mastic
  • Foil tape
  • Packing tape

For the sake of the tests, each of these were used to seal a duct. From there, the duct tape specifically was subjected to an aging test and a baking test.

Duct Tape Aging Test

During the aging test, hot and cold air was shot at the tape in five-minute intervals. The experimenters expected tape failure to take weeks, but it only took a matter of days.

Of each of the tapes tested, duct tape was one of the least effective products. It took 7-10 days for various brands of duct tape to fail. The failure was not labeled as “gradual,” but as “catastrophic.”

Duct Tape Baking Test

In the baking test, which dealt solely with hot temperatures, duct tape also proved to be ineffective. However, the results were much more mixed.

Some duct tapes lasted one month, while others lasted two, three, or four months. The duct tape that had the highest failure rate were the ones with rubber bonding adhesive. In addition, these also had the greatest problems with leaking.

Overall Results

It is interesting to note other products worked much more effectively during these two tests.

The aerosol sealant, mastic, and foil tape all lasted around three months in the aging experiment and four months in the baking experiment.

The conclusion drawn from this was that you should use anything other than duct tape when attempting a repair. This is not to say that duct tape is ineffective, but that there are often better options.

With that in mind, you’ll want to look into these other options if you need a longer-lasting and more durable solution.

What Duct Tape Shouldn’t Be Used For

Like I mentioned before, duct tape shouldn’t be used in extremely hot or cold temperatures. However, there are more scenarios where you should avoid using it.

These includes:

  • Wet surfaces: The liquid will counteract the bonding adhesive and cause the duct tape to fail.
  • UV light: Duct tape’s bonding adhesive will be broken down if exposed to UV light for extended periods of time. If you need to use tape for a project with UV light exposure, there are certain products that are created for this use.
  • Rough surfaces: Certain uneven surfaces such as concrete are difficult for duct tape to work effectively on. Since duct tape is flat, the bonding adhesive will only stick to the surface level.
  • Dirty surfaces: If a surface has any loose material on it, the bonding adhesive of duct tape won’t be able to stick effectively. Make sure to properly clean any surface before using duct tape on it.
  • Skin: Duct tape is sometimes used to make emergency bandages or for wart removal. However, you should be cautious when using it directly on the skin as it can be extremely painful to remove, especially if your skin is sensitive.
  • Life or death situations: Duct tape also shouldn’t be used in any scenarios where it could cause harm to an individual if it fails. Don’t duct tape a rope together if you use the rope while rock climbing. While it’s incredibly strong and durable, you should never place your life in the hands of duct tape.

Other Tapes Made for Extreme Conditions

There are certain types of tape that are created to be more durable in extreme temperatures and weather conditions.

So, if you need tape for a specific heat or weather-related purpose, consider one of the following:

Tapes Made For Heat

  • Flue Tape – This 3M High-Temperature Flue Tape (available on Amazon) is perfect for stopping leaks in air ducts and works in temperatures up to 600°F.
  • Aluminum Foil Duct Tape – This RUI SPEED Aluminum Foil Duct Tape is made for high-temperature metalwork and is perfect for sealing ducts and insulating purposes. The aluminum material it’s composed of allows it to be used in many conditions such as against flames, in UV light, and in most weather while still maintaining its strength and durability.
  • Aluminum Foil Tape – This Tape Plus Professional Aluminum Foil Tape is another great option for repairs involving hot temperatures and extreme conditions. It is designed to stick on any surface and is resistant to UV rays, flames, chemicals, and moisture. The company even offers a money-back guarantee if you are unsatisfied.

Tapes Made For Extreme Weather

  • All-Weather Tape – The Gorilla All Weather Tape (available on Amazon) is created specifically for repairs that need to be made in extreme weather conditions. It’s designed with an extra-durable adhesive bond and a weather-resistant outer surface. However, it should still be used with previously recommended temperatures in mind.
  • All-Weather Duct Tape – The 3M All-Weather Duct Tape is also great for outdoor use. It is designed for long-lasting patchwork and repair, and the extra-flexibility combined with its premium strength and durability makes it great for surviving in various extreme weather conditions.
  • Gaffer Tape – If you need to use tape for an indoor or outdoor repair but don’t want it to be too obvious, gaffer tape may be what you are looking for.

Conclusion

From a technical standpoint, duct tape isn’t flammable.

However, it’s not recommended to use in temperatures over 200°F, as it can cause the duct tape’s bonding adhesive to fail. Also, duct tape will melt if exposed to significant amounts of heat over extended periods of time.

As long as the temperature you use duct tape in is within the recommended range, it should work effectively and remain durable over prolonged periods of time.

Related: Is Electrical Tape Waterproof?

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