continuous filament fiber will never be replaced.

WHY I BELIEVE CONTINUOUS FILAMENT FIBER WILL NEVER BE REPLACED AS AN INSULATING MEDIUM!

An insulating medium has one specific function, and that is to trap air, keep it from moving so when it is heated the heated air stays where it is trapped.

Air sticks to any surface for 1/8th of an inch. This is important to know and will be explained why as you read.

Warm air moves to colder air. This is also important to know.

It is widely known that the colder the environment the thicker the insulation must be. What is not recognized by the companies that produce chopped staple fiberfill for this purpose is the need for density. The method used to make these fiberfill products is always trying to develop the greatest amount of loft with the least amount of fiber. The result is a weak fiberfill product that has no resilience. Initially before the product collapses the spaces between the fibers is so distant that the warm air reaching them does not stop the heated air from continuing to move to cold. There is a lack of density.

To the best of my knowledge all the chopped staple fiber used for fiberfill is in the category of microfibers which have a thickness of three denier or less or as is the case of Thinsulate their fibers are less than one denier. The Thinsulate fibers are so weak that they pack down so tight to the point that there is no measurable amount of air trapped in the fiber structure. This means that when one side of the structure is heated the heat moves efficiently through the structure to the colder area. Anyone who owns a pair of boots that have Thinsulate as an insulating medium in them learns very quickly that they have cold feet. (They are also wet because the boots also have goretex lining in them.)

One more aspect of all chopped staple fiberfills is that they must be quilted in order to keep from separating especially during the laundering cycle.

Continuous filament fiber has been used for many years for yarns and thread and until 1968 when it was used to make pillows the fore runner of a batting as I use it. The next step was to make a batting for use as insulation. What I have learned over the years from 1968 until the present day is that it has some characteristics that can not be duplicated by any other insulating medium; that is its ability to be compressed under 20 tons of pressure as I put it when I vacuum pack survival kits for the Air Force. It has incredible resilience. A second capability is the mere fact that it can be laundered hundreds of times.

Now for the most critical difference. When I sandwich the continuous filament fiber between the nylon and a scrim before cutting it, it has a uniform loft. The fibers are laying on each other but because of the crimp that has been heat set on the fibers they the fibers are spaced apart from each other.

The distance is less that 1/8^th inch so all the air within the fibers is stuck to the fibers and becomes stagnant. Stagnant air like stagnant water when presented with heat will absorb it. If the air is restricted from moving to the cold efficiently it stays within the fiber.

I do not know what can be made that will act more efficiently than the fibers used by Harvest who make the Climashield which becomes Lamilite when I further process it that will perform better than the continuous filament fiber I currently use. What I have learned is that the density of the weights I use work so well that I know the temperature ratings I apply to my bags is conservative. Could I reduce the weight and still maintain the temperature rating, initially yes but I would be compromising the conservative element of the bag’s performance. I know from experience when you fully expect the temperature to be say -15 F it could go to -30 F during the night. I experienced this phenomenon many times when I was hunting the Fossil Ridge Wilderness area in November at 12,000 feet. I never knew it got that cold and colder using my Ultima Thule of Ultra-Light FTRSS.

I have been making the bags with one formula for each temperature rating the same way now for 32 years, so I am not about to make any changes.

Of course, the other characteristic that sets the continuous filament fiber that Harvest uses is that it is silicone coated. Since nothing sticks to silicone the moisture in a vapor state slides past all of the fibers because the air with in the fibers is warm it keeps the moisture in that vapor state until it has moved not only through the maze of fibers but also through the spaces between the yarns of the shell fabric of the sleeping bag or any of my jackets.

I know there are a number of companies that are supposedly working very diligently trying to make an insulating medium that can rival the Lamilite/Climashield but what they are really working at is verbiage that will cause the unsuspecting consumer to think their product is better. But as all who are duped find out the product does not work.

While I know there are people of each generation who want to improve on what came before them and many do make improvements when it comes to an insulation medium for sleeping bags, jackets, mittens, or footwear I do not believe it will ever be possible to replace the continuous filament fiberfill raw material for insulation purposes. In addition when you consider all of the reasons I have noted about the continuous filament fiber you also now know why I believe without question why it is the only legitimate insulation in the world.