So I have two high dollar king size down pillows that I am cannibalizing to make quilts. My mom used to make these pillows at her former job and according to her the down is 750 fill power and there is 36oz of down in each pillow. I used the google spreadsheet the Meteor had posted to help figure some of the fabric sizes. There were a few adjustments I needed to make to the calculations but overall it was a good starting point.
No matter how many times you go over a plan in your head, you just don't anticipate every issue until you're in the middle of it. Luckily I had the master (my mom) with me to help.
I started by measuring me to figure how far up the hammock walls I would want a quilt to come. I settled on 44" width. For the length 46" goes from my shoulder to mid-calf, seemed a good length. I was also shooting for 2" loft. I knew the inner and outer pieces of fabric were different widths and lengths to make up for the baffle and the curve of the fabric. This is where the spreadsheet came in handy. My plan was to make the quilt out of two different fabrics. The outer fabric, black rip-stop from Hancocks (1.9oz) to block the wind and some moisture and the inner some Walmart ripstop much lighter than the 1.9. Maybe 1.1? I was hoping that the black would help to heat up the quilt to evaporate any moisture wicked from my body overnight. I was going to use tulle for the baffles, but I was encouraged to find a different material. I took John Sawyer's advice and bought some organza. I decided to add 4" to my finished dimensions on the inner fabric to make my channels. That way the outer fabric would be hanging from inner fabric so as I tighten my shock cord, I would minimize the compression on the quilt.
Using the spreadsheet I thought I saw some of the same issues with the formulas that were mentioned in the thread about the spreadsheet. I also keyed in 4" for the seam allowance, for my channels, but only the inner fabric needed that much of a seam allowance for my plan, so some of the figures had to be adjusted. Also, for me, where the spreadsheet lists the spacing for the baffles on the inner and outer layers, the sum of the parts exceeded the size of the material it told me to cut. I just adjusted the figures and kept moving.
Anything net-like, in my case organza, is a pain to mark, a pain to cut, a pain to sew; just overall a big pain in the tush. Pins help.
At some point, you realize that you are trying to sew together two squares of unequal sizes. You better have some experience sewing or have a good plan for how to deal with this. The long sides weren't much of an issue, but the short sides took a little thinking. What we worked out was that we pinned the inner and outer material at the baffles to keep them straight. Then we used a pleat between each baffle to get the outer material to match up with the inner.
I've never seen an ounce of down, so it's hard to imagine what that looks like.
The light at the end of the tunnel
So after about 7 hours of planning, cutting, figuring, cutting some more, etc. the shell was finished. I had forgotten my scale so I had to wait to fill it. Once home I weighed it and the shell alone came in at 7.9oz.
Next I attempted to get down out of the pillow and into a container. I started with a mayonnaise jar, it only held .4 oz of down. I then decided to use wastepaper bags. These are smaller bags for 7-10 gallon cans. I opened the bag fully and put my hand into the bag, turning it inside out. Pushing my hand into the pillow where I had one corner opened, allowed the bag to cover the bulk of one end of the pillow and allowed me to gather down and pull it out of the pillow, turning the bag right side out and capturing most of the down. It turns out I can grab right at 1 oz of down with my hands. The bags weighed .2 oz and the 7 bags I weighed with down came in at 1.15, 1.15, 1.2, 1.2, 1.25, 1.25 and 1.3 gross weight so a range of .95 to 1.1. The spreadsheet called for .91 oz with 10% overfill; a little more overstuff won't hurt. You'll see in the picture 7 bags of down at different sizes. These are pretty compressed already so they would loft up even more if the bag were bigger. These are all the size of a bowling ball or slightly smaller.
I'll post finished pics once it is done and I'll hopefully test it soon once it cools off again. I'm shooting for 30* on this quilt and just over a pound in finished weight.