Hunting Sleeping Bag

Climashield Apex is the obvious choice for insulation; it deals with moisture well and doesn't need to be quilted, which makes sewing much easier. For your stated goals I'd be looking at 10-12 oz total weight (i.e. use two layers of 5 oz/yard Apex).

You can source a variety of WPB shell fabrics, but noise will be a concern, especially in the cold. Might want to order samples before you go this route. A lot of the lighter, water resistant nylon ripstops are quite quiet and would serve you fine in anything short of a steady rain. DIY Gear Supply even has 20D "phantom" ripstop in digital camo.

Maybe for shell fabric.

Camo Fleece- Super Waterproof/Breathable-Tex (2-Ply)
http://www.seattlefabrics.com/outerwear.html

Or blaze
Polartec Windbloc® ACT/mesh blocks 98% of the wind, is highly breathable, provides warmth without weight and bulk and is water repellent. This fabric is very durable and creates less noise than a traditional shell.
Washing instructions for all Polartec® fleece
Machine wash in cold water on a gentle cycle with like colors – Machine-dry at a low temperature – or hand to air-dry.
Turn fleece inside-out to prevent pilling
Do not use bleach or fabric softeners
Do not iron, steam, press or dry clean
For best results, launder garment separately.

http://www.therainshed.com/safteycamo.htm

Haven't tried them myself. don't know weights.

Thank you both for the replies.

For the Climashield Apex, I can sew the insulation to the side seam, correct? Any reputable sources for purchases in small quantities?

Any other thoughts would be greatly appreciated.

Yes, just sewing to the seams is adequate.

Thruhiker sells Apex.

“Basically, this will be a sleeping bag. No zipper.”
“Temperatures can fluctuate anywhere from -10 to 30 degrees”

Be sure to make it large enough at the top to allow for some serious venting.
And large enough to allow for “back side” coverage while in a seated position.
And perhaps a cinch bottom al la Nunatak …

Nunatak Raku

Look at the heater body suit and the warmbag for pattern ideas.

The HBS is a bit different cut, but IIRC the warm bag basically is a sleeping bag you wear that has zips for arm holes and a drawstring bottom to close around your feet. Staying warm while stand or still hunting is a challenge.

Just out when it was 10 degrees. My friends dad, now in late 80's, just builds a small fire. In all his successful years of hunting, he says the deer are not bothered by smoke or fire.

A cheap poncho would make a good starter pattern for you- just trim out the waste on the sides until you are happy with the shape. You can use the cut offs to add length if needed and an extra seam at the shoulders if the hood is giving you a headache.

You could then cut two shell pieces and one insulation piece with the pattern- sew all the edges up and then sew the sides together.

On the bottom- I would sew two channels so you can tighten it around each leg/ankle to kill drafts. Just sew about 2" of it together in the middle of the bottom to separate them.

If you are sitting- you may be better off sewing in a sleeve for a CCF pad- then you don't need to waste any insulation there and the pad will be built in so you can't loose it when you stand up.

An easy way to sew this all together would be to sandwich 2 pieces of 5 ounce Climashield inside Insultex (from DYI Gear Supply).

You would just need to sew the 2 pieces of Insultex together and sew the fabric to it.
No need to worry about the climashield stretching.
You would also get a better vapor barrier that you will need while sitting still.

You could put this together with just a few hours of sewing and probably 4-5 of work in total.

DYI also has 70D Taslan 2nds fabric for cheap and in camo color.
The Insultex is already pretty much waterproff, so using an un-coated fabric would help it from being so slippery.

When you work out the design, you also may want to have 2 or 3 drawcords along the body.
Then you can make a simple design and just cinch it to fit you better and hold in more heat while also allowing better venting options while you're sitting.