Here is the prototype that I made this weekend of a 2 layer IX TQ that a HF member asked me to make for him.
Finished the TQ prototype Saturday. Slept in it Sat night.
Very impressed with warmth , but not happy with footbox design.
Altered footbox significantly Sunday, will test it one night this week... likely Monday or Weds.
The original footbox was just a tapered cone with a drawstring in the bottom.
I hated it.
It was smallest at the bottom, which is where my size 13 feet were.
I added in a triangle to the bottom of the footbox seam (not the end, the bottom) to expand the foot area, but it was still too snug.
So I added a 12"x10" panel with 2 layers of IX and made a vent in it.
Holy cow, it is SOOOO much better.
I'll keep thinking about the vent though. Not really happy with how the small circular vent is attached.
Likely to make a rectangular vent that sticks out less in the one for the HF member.
The 50" width is great. I was afraid if it were too narrow that any movement would cause air gaps or the TQ to slip off of me. No issues with that at all. I will make the HF member's TQ with a bit less width to save a bit of weight. The 6" draft tubes on each side really reduce the risk of making it more narrow.
Shell is 1.1 rs from BWDD, IX from BWDD, inner shell is a non-rs nylon that is really soft and great against the skin. Drawcord and mini toggles from BWDD (love the new 2 hole mini toggles).
I made a stuff sack that is about a foot long and 7" wide. I thought this TQ would just barely fit in it. However, I can stuff (not roll) the TQ in the sack AND cram my 96" x 60" fleece TQ in the same sack. Total size is about 1/2 the size of the mummy bag that I have been using as a TQ.
I think I'm finally at the point were I'll have to go get a postal/food scale. It kills me to make this cool stuff and not know exactly what it weights.
Attached a few pics of the prototype. Each picture has a number in the name.
63 = prototype with the conical bottom and drawstring
65 = the hollow draft tube that hangs on each side. Tuck it under you to seal out any drafts
66 = original drawstring bottom
73 = top with drawstring to cinch around shoulders
77 = new footbox bottom with round vent
62 = modeling different design concepts
86 = I sewed 4 rows of longitudinal 1/4" pleats in the bottom layer of IX to provide an air gap between IX layers. This also reduces the inner IX layer width to help it wrap around the person using it.
74 = the IX TQ AND my extra large fleece TQ both in the stuff sack.
With the new footbox design I can pull my 80" long TQ up over my head. With the tapered footbox i could only get it to my shoulders.
I'll make the final version next weekend. In the mean time, please share any thoughts or design ideas.