Awhile back, i posted about a using foam to create a layer of more stilled/trapped air in conjunction with a windjacket, but still being mostly breathable. Sort of like the concept of fishnet.
The idea had some definite potential, but had some issues too. As tough as Evazote foam is for a foam, in thin forms, it just lacks the necessary tensile strength to be durable in more clothing type form, especially with numerous holes cut into same. Plus, fit was an issue. The foam at the shoulders would puff out the windjacket too much, negating some of the trapped air concept (too much air space allows increased convection).
Came up with a simple fix. Bought some Argon nylon from DutchWare (waiting on it). This is one of the super light nylons, but being nylon and tightly woven is still fairly durable and strong–at least for it's weight.
I'm going to take a single piece of fabric and cut to the shape of a vest. I will cut some straight foam strips (haven't decided if i want to punch holes in same or not). I will take some Argon and cut strips slightly wider than the foam strips and sew these onto the single piece of Argon fabric in a X like formation, and also with some horizontal and vertical pieces, so more like a *.
Sew the strips of Argon onto the fabric. Sew closed one end, leave one end open and sew corresponding velcro on a flap at the one end.
I will cut a corresponding piece of argon to the vest shape, but only matching to the lower shoulders area. So there will be an arm and head holes to put my arms and head into, but no fabric down on the lower back. Again, with a backpack on, you don't need any extra insulation during active conditions.
Foam strips go into the sleeves, and secured with the velcro flap on the ends. When washing the garment, you can take the foam out.
The Argon/foam vest will be worn with the foam strip side touching the skin, lifting the rest of the fabric off the skin from approximately 1/4 to 1/2 inch depending on what thickness of foam i decide to use.
Most of the stress will be taken by nylon which has the much higher tensile strength.
This could be used in combo with a fishnet baselayer or a Cap 4 hoody, in more severe cold temps and increase warmth and comfort at a low weight, without having to worry about moisture at all. Such a thin nylon with little space for air in the material will dry very fast, the foam doesn't absorb any moisture and is very thermally resistant, course you have all that void area with layer of air.
The only problem that i can see, is that Argon is not particularly breathable. It's like a windshirt material itself. I wish i could source a more breathable, lightweight nylon. I've thought about using the non calendared, very breathable 30D nylon that i used for my Apex vests, but i'm trying to get lowest weight possible. I'm looking to get this to weigh in less than 3 ounces, which if i use the Argon i think i can do with no problem.
Will post pictures when project is finished. Any feedback about how wide the foam strips should be, if i should punch holes in them or not, etc would be seriously considered and appreciated.
