Why Lamilite
Why Lamilite Insulation?
The single most important component of any insulated product, be it a sleeping bag, parka, bib, snowsuit, booties or mittens, is the insulation inserted into these products. All insulated Wiggy's products have only one insulator: Lamilite.
Lamilite, which uses a continuous filament fiber called Climashield® by Harvest, CI, Inc. as its main component, is the best material developed thus far for use as insulation in sleeping bags or outerwear. I believe a sleeping bag is the most important piece of equipment you take into the field. The wrong one can mean a very unpleasant camping trip, or worse.
The functional difference that truly sets the Wiggy's Bag apart from the rest is its insulation! Lamilite possesses an extraordinary quality that helps contain the flow of heat that your own body generates. The key to Lamilite is its ability to allow the body's own thermostat to function efficiently.
Lamilite is Lofty Insulation
The more loft surrounding your body, the more difficult it is for your body heat to escape.
Lamilite is Lightweight
The lighter the weight of the insulation the lighter the weight of the finished product be it a sleeping bag or garment.
Lamilite is Very Soft
Put on a Lamilite parka and you will automatically think it is a down filled parka. The same holds true for our sleeping bags. They surround the body much the way a down bag does, filling in or draping closed around the body. This eliminates heat loss from convection. Conductive heat loss is reduced significantly. The fiber used for Lamilite is not densely packed into our products (as will be explained later) therefore, the loss of heat via conduction is minimized.
Lamilite is More Than the Fill Put Into Our Sleeping Bags
It is a combination of nylon fabric and fiberfill, two components that aid each other. The first part is visible. It is the 70-denier nylon commonly known as single ply taffeta. The 70 denier refers to the thickness of the yarn. The actual weave is 86 yarns in one direction and 104 yarns in the other, per square inch. The thickness of yarn is the optimum thickness to absorb body heat and quickly warm to your body temperature. The faster this warming occurs, the slower the rate of conductive heat loss from your body. The spaces between yarns in this construction allow the moisture your body produces to easily escape. It is irrelevant how dry a climate may be, your body gives off moisture. Therefore, it is important to allow this moisture easy exit. Water is extremely efficient at absorbing heat, so you always want to stay as dry as possible.
Our exclusive processing of the fiberfill laminates the nylon. The Lamilite is an unbounded, silicone-coated continuous filament fiber. This is inside and cannot be seen. The silicone coating gives the fiber two very desirable properties. The first is "antistatic" which allows the fibers to perpetually repel each other regardless of how tightly the fibers are packed against each other (such as compacting in a stuff sack). The loft always returns after removing our sleeping bag from the stuff sack. As an example, one of our Ultima Thule sleeping bags was compacted under 20 tons of pressure. It was blister packed in two poly bags the size of 14 1/2" x 9 1/2" x 2 3/4". After four days it was opened and in one hour, without assistance, 90% of its loft returned. A Lamilite insulated sleeping bag is the only synthetic bag ever put through this test that returned to its original loft. The Alaska National Guard, as part of their survival gear, uses the Ultima Thule. The bags are left in the vacuum package until needed. In 1994 the U.S. Navy authorized an Ultima Thule, vacuum packed, as the official survival bag carried by aircraft and ships. In addition, they determined that it actually performed at -35°F. The second benefit of the silicone treatment is in making the fiber HYDROPHOBIC. Hydrophobic comes from the word "hydrophobia," or fear of water. Water simply does not attach itself to the fiber. This is extremely important for the moisture leaving your body, passing through the spaces between the yarns and easily moving through the fiber. Also, it is extremely important for the moisture not to condense in the insulation. If this occurs when temperatures are below freezing, frost buildup can severely reduce the thickness of your insulation and add weight.
Refer to the Steger Expedition to the North Pole in 1986. They used 15 pound chopped staple fiberfill insulated bags that accumulated 35 pounds of ice. Even though that fiber was silicone treated, it was so densely packed in by the quilting that it prevented any flow of moisture while in a vapor state.
Lamilite Insulation is Very Drape-able
It is important the insulation of a sleeping bag drape around your body. The closer the insulation hugs your body, the less convective air movement occurs. The fiber pushes down on your body and the nylon lining touches your body. If the nylon did not touch your body, the heat from your body would be heating the air space directly above you and a convective air current would be generated. But with the nylon touching your body, it absorbs your heat quickly until it reaches your temperature. This heating action then slows, thereby reducing conductive heat loss.
Lamilite is Also Easily Laundered
In fact, Wiggy's wants you to wash its products when they get dirty. When you go camping, you get dirty and so does your sleeping bag. After awhile, the dirt works its way into the insulation and combines with your body oil. This in turn causes the insulation to compact down or reduce loft, hence, loss of insulation. Therefore, it is important to wash your Wiggy's bag after each camping trip. Keeping the fiber clean will allow it to retain its original loft. Learn more about our care instructions. They are sewn into every bag.
Lamilite Insulation: Simply the Best!
All insulations, regardless of composition (synthetic fiber, down, wool, cotton) function exactly the same way. The thicker they are the better. As Gerry Cunningham once wrote "a ¼ inch jacket is only ¼ as warm as a 1-inch jacket.”
There are several factors that account for one insulator being better than another.
A. Loft for Weight - Since the mid 1960's, when camping became enormously popular, down has held the reputation for being the lightest weight insulator with the greatest amount of loft, for its weight. Considering what was available, it justified the #1 rating. In October of 1986, that changed. I developed the technology to use a synthetic fiber which had been used for 22 years as a pillow stuffing; an unbonded, silicone treated, continuous filament fiberfill. Ounce for ounce, it is approximately 25% loftier than all other synthetics, and—when used as insulation in sleeping bags—there is virtually no difference in loft or weight for each temperature range versus a down bag, when they are of equal size.
B. Compactability - When comparing LAMILITE to down, the compactability factor is equal. No other synthetic insulator even comes close.
C. Effects from Moisture - Moisture and down are very compatible. Down absorbs moisture like a sponge. Using waterproof, breathable fabrics for the exterior will prevent water from getting to the down, but the real problem comes from the moisture the body emits. Once body moisture changes from vapor to liquid, it is absorbed by the down. Unless there is lots of sunshine to dry your sleeping bag, the lofting ability is decreased by the damp down. LAMILITE fiber not only doesn’t absorb moisture but allows the moisture, while in a vapor state, to pass through it easily and quickly. This is because of the silicone treatment which acts like a lubricant. Therefore, water in a vapor or liquid form does not affect the LAMILITE.
D & E. Longevity to Perform/Ease of Care - I group these two subjects together since the care of each of the insulators is vital to its overall performance. Down must be stored a certain way, laundered a certain way and, since it is a natural product, will deteriorate over a period of time. The care given to down will determine its longevity.
LAMILITE, on the other hand, is an easy care product. A LAMILITE sleeping bag (WIGGY'S BAG) is launderable in warm to cool water and dried at a low temperature setting in standard machines. A good practice is to launder a LAMILITE bag whenever it gets dirty (generally after every use). LAMILITE is so resilient, it can be stuffed in its stuff sack for storage. Considering the loft is long-lasting, it will always perform.
The Physics Behind Lamilite
Lamilite, Climashield, continuous filament fiber: 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 since Wiggy’s began manufacturing sleeping bags, continue to perform exceptionally well.
The physics of insulation shows that continuous filament is truly in a class of its own.