Hi Steve, I have a pattern I started with but modified over the course of making 3 of them. Basically, I tapered from about 40” to 50” from the footbox end to about knee height. On one of the quilts I did the outer shell a little larger than the inner, but it turned out to not be a big difference.
For the portion of the quilt above the knee, it would be very easy to just taper simply until about mid torso, where you just use the full width of the fabric, in my case, the Hyper D is about 58”. I just liked the idea of trimming extra weight, so I scalloped it out in the butt area and tapered at the shoulders. It actually worked really well, and got all the quilts right around 17.5ish oz with 3.6 Apex. The cut leaves the back area pretty exposed to the sleeping pad, but has enough wrap around as long as one is not too girthy. I added pad straps for each of the quilts. The attachments should be at mid to lower torso, at least my preference, so you could sit up easily without the straps getting in your way.
For construction:
the inner shell and outer shell are constructed separately, unlike most flat apex quilts. There are a couple of folks on Reddit who documented their projects I followed. I took some pics, but not of the whole project. To make the shells, I started by sewing the left and right sides of the footbox together. This gave the tube shape, and then I had to sew the round cap into the end. It is just a little math, but a 40” foot box is about 13” diameter cap. You’d want to do the math to get it right for whatever yours ended up being. I sewed the Apex to the outer shell by sewing the layer of apex to both the shell (around entire perimeter) and also to the circular cap, and then sewing them together. For the inner shell, when sewing the left and right footbox together, I left a 6” space in that seam open, for the purpose of flipping the quilt inside out after putting the two halves together. That ended up being the place I thought would see the least abuse, since that is where I blind-stitched the area closed after everything was done. You could choose other places though if you wanted to.
With outer and inner shell completed, they go together much like normal apex quilts do – add your doodads (drawstring tube, grosgrain loops, padstraps) in between the layers and keep them in place with clips, then just sew the perimeter shut. Then you just pull it inside out through the hole in your seam, wherever you made it, and sew that hole up. In my quilt, the inner footbox liner floats; i.e. it is not tacked to the Apex or the outer shell. You could tack it down with some hand stitches if you wanted to so it didn’t move, but I didn’t really think it was necessary. All my guys loved the quilts and kept them nice and warm. Temps were in the low 40s at night, so they were perfect.
I’ll attach some pics of the builds if I can find them.
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