I have posted about my Down Karo Step top quilt design and my Bridge Down Under quilt design previously.
I have completed the design, construction and testing of my Insultex quilts, both the top quilt and a Bridge Under quilt.
All of my Insultex quilts use 3 layers of the Insultex material.
I learned last year in experimenting with my Insultex hammock which was a Bridge hammock with the Insultex sewn directly to the bottom of the hammock, that it was necessary to have an air gap between me and the Insultex. I knew this already from what I had read of the i.d.i.gear Arctic Armour outfits. The people using those outfits advised getting a size at least 2x bigger than a person normally wore so that the garment was not pulled tight against the wearer at the shoulder, knees, elbows or butt. If the garment was pulled tight, a cold spot developed.
I'll describe my top quilt first. In order to keep the Insultex from being pulled tight against the user, I designed a differential cut top quilt:
From the illustration you can see that in order to keep the Insultex from being pulled tight against the user, I have made the inner shell 50" wide and the Insultex layers and outer shell all 60" wide.
I have also incorporated 6" draft stoppers on each side and draw cords at both the foot and head ends. Since I made the top quilt 50" wide, the draft stoppers are not really needed in a hammock and are there primarily for a go to ground capability. Since the Insultex material is 60" wide, making the top quilt as wide as possible and utilizing the full 60" width didn't cost any more. A definite advantage over down where any added width or length cost in down filler.
I decided on an 80" length since that gives plenty of top quilt to cover the feet and the head. With an 80" length, it should be possible for even someone 6' 4" or 5" and possibly more to wrap their head with the quilt.
The final dimensions of the quilt are 80" L x 50" W. In the JRB stuff sack it weighs 27.80 oz. This compares favorably with my Down Karo step top quilt at 27.30 oz in the same JRB stuff sack.
Here's the top quilt with the foot box formed. If you look closely you can see the draft stopper on the near side and the extra material for the Insultex and outer shell:
Here's the view with the foot box opened and the inner shell of the quilt. You can see the draft stoppers on both sides here:
For the under quilt, I again used a differential cut to maintain the air gap between the user and the Insultex. My Bridges are all cut with a 44" end width and a 6" arc depth. For an under quilt, the top shell is an exact duplicate of the Bridge Hammock using 1.75 mm guy line cord on the arcs. The Insultex layers and the outer shell are all cut with a 60" end width and a 9" arc depth. The added arc depth is necessary to keep the Insultex and outer shell layers from pulling up and above the Bridge Hammock arcs when the Bridge Hammock is occupied. This would eliminate the needed air gap.
The under quilt is attached to the Bridge Hammock quite simply and easily by using the arc guy line cords by tying with a toggled half hitch on suspension triangle cords at the Bridge Hammock corners. I have found that this design for a Bridge under quilt necessitates that the top shell fabric be an exact duplicate of the Bridge Hammock it is used on and that the corners of the under quilt must line up exactly with the corners of the Bridge Hammock. By using the same pattern for the top shell fabric as was used for the Bridge, doing this is very simple and easy.
Here is the Insultex under quilt laid out. First showing the outer shell:
Then the inner shell:
In the JRB stuff sack the under quilt weighs: 22.95 oz. This compares favorably with my down bridge under quilt at 22.95 oz in the same JRB stuff sack. Surprisingly the weight of the Insultex under quilts came out exactly the same as the down under quilts. - this was not planned.
I have used the top quilt and the under quilt together this winter and find them to be toasty warm and extremely comfortable. With the differential cut of the top quilt, the top quilt feels as good against the skin as the down top quilts. The coldest I got this winter was 11° F and I was toasty warm wearing only cotton briefs, cotton Tee and cotton socks. My down top and under quilts all have between 5" and 5.5" of loft and according to one web site I found in the past, I believe that that should be theoretically good to about -20° F. I have no way of knowing just how cold the 3 layers of Insultex can go. The only thing I have there to go on is the experience of ice fishermen who report that they are comfortable sitting around in their Arctic Armour gear down to single digits F wearing the same thing I wore.
Shown here are the Insultex top and under quilts in the JRB compression sacks alongside my down Karo step top quilt and down Bridge under quilt. I have included a 32 oz Nalgene bottle for size comparison:
The Insultex quilts are on the top with the down on the bottom. The under quilts are on the left and the top quilts on the right. All of the compression sacks are 7" diameter. All are 9" high compressed except the down under quilt on the bottom left which is 8" high. All were compressed as much as possible by stuffing, rolling the top twice, kneeling on the sack and cinching the strap down as tight as possible.
The Insultex top and under quilts have now become my preferred and go to quilts. This due to several reasons:
- comfort - the Insultex top quilt is as comfortable as my down top quilts
- temperature - I know that I can get to 11° F with minimal clothing and feel another 2° F to the single digits would be easily possible with the same clothing. I feel that by adding my merino long johns which I reserve for night wear, I could be comfortable even lower.
- weight - the Insultex quilts are equal to or only 0.5 oz heavier than my down quilts.
- coverage - the Insultex quilts are full coverage. Since the cost for full coverage was exactly the same as for limited coverage, I opted to make the Insultex quilts as big as possible. This was not possible with my down quilts since the cost of down became prohibitive, even with Ed's generous HF discount.
- bulk - even making the Insultex quilts as big as possible, they are the equal of the down quilts compressed in the JRB compression sacks.
- compression - I can store my Insultex quilts compressed in the JRB compression sacks as shown. This makes them always immediately available when I go into the field. This definitelty cannot be done with my down quilts. This isn't something that would keep me from using down, but for convenience, this is great for me. This could be something that would definitely keep somebody from using down and instead using the Insultex if they were considering a BOB. For the BOB, the extremely high priority of grab and go precludes down. The Insultex quilts would be ideal for a BOB.
- the Insultex is impervious to water. This is a big advantage over down. I haven't tested yet, but I'm pretty sure the Insultex quilts will be field dry-able, which down is not. This also makes the consideration of rain blown under a tarp much less of a concern than for down.
- I can use uncoated fabrics throughout. Down proof fabrics are needed for down, which are usually DWR coated fabrics. The DWR coating makes the fabric heavier. The uncoated fabrics are better for passing any condensation through and not trapping it.
I will be switching to my Insultex quilts for all of us in the future. Just too many benefits not to do so.
The compressed bulk and weight is equivalent to my down quilt design.
Weights in JRB compression sacks:
Down top: 27.30 oz
Insultex top: 27.80 oz
Down under: 22.95 oz
Insultex under: 22.95 oz