Why Does Lamilite, Climashield, Continuous Filament Fiber Work So Well as Insulation? They Are All One and the Same.

I have written extensively about Lamilite, but until now, I did not fully understand the physics of why it works so well. Now I can explain it.

Several factors contribute to its success.

Factor number one, and the most important, is to leave it alone with respect to its loft.

When the continuous filament comes off its web-forming machine, it is now Climashield, and it can be produced in several different weights or thicknesses. They manufacture weights between 3 ounces and 15 ounces. I primarily use 6, 12, and 15 ounces.

When I receive a shipment of Climashield, I further process it by laminating it to nylon, and it then becomes Lamilite. What is important to note is that the loft of each of these three products has not changed. It remains the same loft level as when it was first made. Remember, maintaining loft is the key to staying warm.

The reason for lamination is to assist with cutting and sewing, which makes manufacturing more efficient and extends the long-term life of our products.

Now, to the physics at work.

Let’s take one of our sleeping bags as an example, such as the Super Light 0°F-rated bag. Before getting in, you may notice the uniform thickness of the sleeping bag from the foot to the head. This means the heat from your body moves upward, toward the sky. That heat travels from your body to the nylon. Once it leaves the nylon, it enters the fiber, where it attaches to the filaments. The Super Light bag contains L-15, or 15-ounce Lamilite. If you were to cut an 18-inch-wide section from the sleeping bag and count the individual continuous filaments, you would find approximately 8 million strands or more. The thickness of the insulation is between 2 and 3 inches.

Warm air does not move quickly within the bag. The filaments have a crimp, causing them to touch each other at various points, which significantly reduces the movement of heat transfer. This is why trapped heat forces vapor out of the sleeping bag. The density of the fibers keeps warm air movement to a minimum, while vapor movement remains constant.

Because heat escapes from the sleeping bag so slowly, it has a very positive effect on your body. The slower loss of body heat reduces your metabolic rate, which, in turn, slows the digestion of the food you ate before getting into your sleeping bag.

In contrast, if you enter a poorly insulated sleeping bag, you lose body heat quickly, causing your metabolic rate to increase. Once you’ve burned through your food reserves, you start feeling cold.

The slower your body digests food and the slower your heat loss, the longer you stay warm. This is a trademark feature of Wiggy's bags.

Layering the insulation significantly enhances temperature ratings.

For instance, when you use a Super Light 0°F sleeping bag with an overbag rated for 35°F that contains L6 Lamilite, the combination is rated for -40°F. The temperature capability becomes disproportionately more efficient relative to the increased weight.

In our Antarctic bag, we use three layers of L-15 and one layer of L-6 for a -60°F rating. Given that this setup contains more than 24 million filaments, heat loss, even in a -60°F environment, is minimal. Of course, other factors come into play, such as the fact that you are usually clothed. However, what’s remarkable is that even if someone is wet and clothed inside the Antarctic bag, they will still warm up, and the moisture will dry out.

Another interesting fact is that the Antarctic bag, weighing only 7 or 8 pounds, is remarkably light for such extreme temperatures.

You now understand the physics behind continuous filament fibers’ insulation properties. It’s important to note that the weights used in Wiggy’s bags, which have been in use for the 37 years that Wiggy’s has been manufacturing sleeping bags, continue to perform exceptionally well.

The physics of insulation shows that continuous filament is truly in a class of its own.