Editor’s Note: Before buying any heat protection, exhaust wrap, header pipe wrap, or other insulation, it is imperative to educate yourself about the product and the application. We talked to Steve Heye, vice president of HeatShield Products, Inc., who shared the following advice on choosing the heat insulators or barriers for your application:
First things first—do your homework.
You must first decide if you have a conductive heat issue or a radiant heat issue. Conductive heat transmits from the heat source to a component by direct contact. Radiant heat radiates from a heat source to a component that is not in direct contact with the heat source; instead it sits at a distance. For example, an exhaust pipe one inch away from a floor pan can radiate heat up to the floor pan. Conductive heat is a little more difficult to manage, but you can try using a heat insulator product to act as a thermal gasket to help minimize the transfer of conductive heat from component to component.
Check your temperature ratings for your application(s). If you have access to an infrared temperature gun, use it to measure the temperatures of the heat source and the component you want to protect. In addition, measure the distance between the component and the heat source. By doing this, you will find the correct solution to your problem right away, saving you time and money.
You would not buy a pair of cylinder heads or an intake manifold without finding the correct application; do not do the same thing with thermal insulation. To help you find the right solution for your needs, HeatShield divides thermal insulation products into two main categories.
Heat insulators retain heat in what they are placed upon.
The most efficient way to fix a hot firewall, interior, or fuel cell is to stop heat at the source with an insulator. Most insulators are exhaust wraps, but there are other options. Typical insulators (wraps) available on the market are comprised of fiberglass, which is good for 1,000 degrees F of continuous direct heat. Fiberglass wraps can have special coatings applied to them such as “Vermiculite,” graphite, etc., which allow the fiberglass to take 1,200 degrees F of continuous direct contact. Heatshield Products has even developed a proprietary HPTC coating which allows the glass to sustain 1,350 degrees of continuous heat. In addition, the wrap will remain flexible, strong, and abrasion-resistant even at those temperatures.
Be cautious of any fiberglass wrap advertising or labeled as 2,000 degrees F as this number is the maximum temperature a fiberglass exhaust heat wrap can withstand for less than 30 seconds. Anything above 2,000 degrees for an extended period of time will cook fiberglass exhaust wrap, causing it to get brittle and fall apart. That is because it exceeded the 1,200-degree continual operating temperature, and the chemical make-up has actually changed and crystallized.
Have you ever had a basalt (volcanic rock) wrap get brittle and fall apart? Much like the fiberglass exhaust wraps, the volcanic rock (basalt) exhaust wraps cannot sustain 1,800 degrees continuous, instead they are designed to sustain operating temperatures of 1,200 degrees F and take brief intervals of 2,000 degrees F for 30 seconds or less. So if yours has become brittle you need to upgrade to a higher temperature wrap such as Inferno Wrap or Heatshield Armor.
Exhaust pipes, mufflers, and catalytic converters are typical sources of radiant heat. Exhaust heat shields, such as HeatShield Armor, are ideal insulators to manage this heat.
Heat shield barriers act as a thermal barrier to stop radiant heat and are placed usually 1-inch away from the heat source on the “hot side” (underneath the floor pan, engine side of firewall, transmission side of trans tunnel, etc.). The most common type of radiant barrier is aluminum combined with a fiberglass, silica, or ceramic insulation.
Again, be leery of any company advertising aluminum heat shield barriers that have a contact rating to 2,000 degrees or higher. Aluminum melts at 1,120 degrees; however, if you have a 2,000-degree heat source that 2 inches away with a lot of air flow, an aluminized barrier still might work. That’s because air gaps and air flow are huge factors when using a heat shield barrier. With the right combination of an aluminized barrier, air gap, and air flow, most aluminized fiberglass barriers are capable of reflecting over 90 percent of radiant heat away. If the application has less than one inch of air gap between the heat sources or has some direct contact points, these aluminized barriers are only good for temperatures of 500°F, and might only stop 50 percent or less of the radiant heat.
Lava rock barriers (basalt) are another good product for reflecting radiant heat. While basalt may not reflect as much heat as the aluminized heat barriers, they will perform more efficiently when you have less than an inch of airspace between the heat source and limited airflow. Products like our Lava Mat can sustain 1,200 degrees of continuous heat and actually stop more heat than an aluminized product in the same environment. Also keep in mind, because one thing may work for one application, it can function completely different when the environmental conditions are changed. But if you use the one inch of airspace/good air flow guide, it will keep you pretty safe.
Please note that heat shield barriers do not work inside your car! Sound dampeners with aluminum do not reflect heat. While they may reduce heat inside slightly, the aluminum on that sound dampener is designed to dampen sound, not heat. We recommend a dedicated undercar heat barrier, such as the Stealth Shield. It has proven technology that will significantly reduce heat underneath your carpet and can even be used above your headliner or sewn into a convertible top.
Remember, measure (temps) twice, cut once! As always, wear a safety mask, gloves, and goggles before you start playing with any insulation!