DIY Multicam Synthetic Winter Top Quilt with Sewn Footbox

**kitsapcowboy** · 10-21-2016, 17:36

OK, I now have over a dozen DIY synthetic hammock quilts of one sort or another under my belt, including 20F, 30F, 40F and 50F top quilts made with Climashield Apex isulation ranging in weight from 2.5 to 7.5 ounces per square yard; I've done a number of zipper/drawcord closures, but for this wintertime top quilt it is the first time I've attempted a sewn footbox...

What a nightmare!

I spent almost as much time last night picking stitches out of my first version of the footbox as I did sewing it together in the first place. I had to be extra-careful too, since I had chosen nicer and more expensive materials for this quilt than I usually do -- a Multicam Epsilon 1.55 oz outer shell, an Argon 90 0.9 oz inner shell, and Climashield Apex 7.5 oz insulation in between.

Long story short, my initial design of the top quilt's footbox was errant in its construction and left me with cold spots where the insulation fell away almost vompletely inside the shells because it wasn't properly tacked in place. I remedied this in the second version by adding an additional shaped layer of CS 3.6 in the footbox inside the 7.5, which I basted in by hand -- making the footbox super-warm with just over 11 ounces per square yard of fill and nearly 3" of loft!

Here is my result...

Type/Rating: 20-degree F synthetic top quilt
Outer Shell: Epsilon 1.55 oz ripstop nylon in Multicam
Inner Shell: Dutch Argon 90 0.9 oz ripstop nylon Coyote Brown
Construction: Rectangular (no taper), rectangular sewn footbox
Overall Length: 78"
Overall Width: 58"
Torso Insulation: CS 7.5
Footbox Height: 13"
Footbox Width: 15"
Footbox Insulation: CS 7.5 plus additional CS 3.6 (double layer)
Weight: 39 oz(!)

(Details on construction and lessons learned to be posted here later...)

**ylnfrt** · 10-21-2016, 22:26

Good looking TQ- really like multicam. Is your footbox just a flap folded over- looks that way in pic 2?

**Texas_toothpick** · 10-21-2016, 22:55

I really like it. Great job.

**kitsapcowboy** · 10-21-2016, 23:47

Originally Posted by Texas_toothpick

I really like it. Great job.

Many thanks! Despite the weight and bulk, I'm excited to test it out this winter.

Originally Posted by ylnfrt

Good looking TQ- really like multicam. Is your footbox just a flap folded over- looks that way in pic 2?

Thanks. In essence, yes. It is a contiguous rectangular extension at the bottom edge of the quilt shells, constructed into a 3D box by wrapping the bottom edge of the main section of the quilt around the perimeter of the extension (different than a flat-sewn footbox)...but that was really the source of my woe on this particular quilt project.

When I originally designed this TQ and cut out my blanks, I added a centered extension of fabric at the bottom edge that was 14" tall and 17" wide on each blank. I figured keeping each of the shells all one piece eliminated a seam over one's toes at the top of the foot box, allowing for a continuous layer of CS insulation. My initial thinking was to sew the entire quilt perimeter of the materials stack except for the very bottom of that extension (anchoring the insulation), invert the quilt right side out, and then construct the 13"x15" footbox by sewing the bottom edges of the main rectangle around the perimeter of the extension, sandwiching a tubular insulated baffle into the seam on the inside of the footbox along three edges to stop drafts. What looked good on paper was a travesty in actual execution; the insulation at the sides of the footbox -- especially at the top corners just outboard of one's toes -- just wanted to pull away completely from the perimeter seam, to the point where there was virtually no batting there, and you could practically feel the inner and outer shells rubbing together with essentially zero loft. No bueno...

What I wound up doing after seam-ripping the entire sewn footbox to fix this problem was a twofold solution:

1) First, from the inside of the footbox with the CS and inner Argon flayed aside, I sewed up the entire outer shell of the footbox together. Next, I performed virtually the same operation on the Climashield insulation layer, except I basted it by hand with a needle instead of sewing by machine. Then, I performed virtually the same operation on the Argon inner shell, except I except left open the seam edge on the heel side, facilitating completion of the second part of the fix (see step 2 below). All of this was easier said than done; material management of this bulky quilt and order of operations in reassembly was critical to sewing it all back together successfully.

2) I cut a 23"x25" piece of CS 3.6 insulation, folded the corners, and basted it by hand using Mara 70 thread and a yarn needle into a rough box shape 13"x15" at the base and about 5" deep; I then tacked and basted this extra insulation layer as a sort of "cap" over the main CS layer I'd already stitched back together into a footbox configuration(see attached photo). (Once the quilt was reassembled, the extra 3.6 "cap" layer would be flipped inside out and actually form the inside lining of the footbox between the CS 7.5 and the Argon.) To complete the revision, with the shells and insulation back in proper orientation, I sewed the remaining inside seam on the heel edge of the footbox closed by machine, now covered with with a much smaller 15" tubular baffle, making for a fully insulated and much warmer sewn footbox.

Knowing what I know now, even after having achieved a workable design through this process of trial and error, I would only bother to sew a constructed footbox (as opposed to a much simpler flat-sewn one) on a top quilt I intended to use in temperatures below the freezing mark; the sewn footbox is roomy, comfortable, and warm, but IMHO it's just too much trouble compared to a simple drawcord closure if you're not needing to fight serious cold.

**kitsapcowboy** · 10-23-2016, 13:52

FYI, the insulation cap of extra CS 3.6 I added around the inside of the footbox weighed approximately 60 grams, so if one constructed a similar sewn-footbox top quilt from the start the way I did it upon revision, one could omit the exta insulation cap, baste the 7.5 oz layer together tightly, and save about 2 ounces, bringing the quilt down to around 37 ounces in total pack weight. Personally, I'm OK with the minimal weight penalty, warm feet, and peace of mind this winter...

**ylnfrt** · 10-23-2016, 18:44

R+D can be a &itch at times but it sounds like you came up with a good solution. I have learned that the assembly procedure is often as complex as the concept. Thanks for your detailed explanation of your footbox- I like it. Congrats on what should be a good winter quilt.

**WalksIn2Trees** · 10-23-2016, 20:48

Does anybody know the heat transfer coefficient for climashield? Or any of the synthetic insulations? Is there a chart somewhere?

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**kitsapcowboy** · 10-23-2016, 21:53

Originally Posted by WalksIn2Trees

Does anybody know the heat transfer coefficient for climashield? Or any of the synthetic insulations? Is there a chart somewhere?

Climashield Apex insulation has a CLO value of 0.82 per ounce; as I understand its use in measuring thermal resistance, CLO is proportional to the R-value by a factor of approximately 1.13, so that would give CS 7.5 an R-value of just under 7. That's about as close as I can get you, understanding that R-value (thermal resistance), C-value (thermal conductance), and K-value (thermal conductivity) are different (albeit related) quantities with different dimensions...

This article explained the various statistics surrounding heat transfer and insulation really well, IMHO...

http://www.insulation.org/articles/a...fm?id=IO090302

I've heard many members here recount the adage, "It's not rocket science; it's a hammock..." After reading this article, I beg to differ...

**Bikecop** · 10-31-2016, 13:24

my first boss told me "nothing is EVER easy" and he's been proven right again and again.

Hey kitsap, the topquilt you made with 5 oz climashield...what does it weigh?

thx