A Simpleton's Differential Cut UQ*

[Schneiderlein]

Yes. It is probably not the best use for that fabric (better for something that is closer to the body to take advantage of the softness) but I've had a couple of yards of that for half a year, and it is light. And looks really nice.

I have a couple of yards of that stashed away somewhere. It does look really nice, but I remembered it very differently from your pictures.

One could try tapering the mesh on a curve so that there's not an angular corner. I still would not try that corner with the hemming foot, but you could do that part by rolling the hem by hand and pinning. Alternatively, one could cut a separate piece of mesh for the vertical portion of the outer body, wide enough so that after it is sewn at the very end (abutting the long main piece, it can be swiveled up so that the extra bit overlaps with the main piece, and then attach the two pieces of mesh sewing stitches by hand. That is essentially what I did except I used glue to attach the extra piece to the body...only because by the time I realized I had a problem, both bodies had been nicely attached to the long baffles.

If hand-sewing is involved, I think one could skip the extra piece and sew the baffles on the shell first. Then, make a cut and do the swivel thing you describe. For a quilt with that much loft, I think the first couple of inches could even be done by machine, leaving enough to get the rolled hem started. I'll have to experiment...

It's 1/8". I miss-remembered but went back and checked. Not sure what weight cost is in that. Not enough to worry about.

1/8" sounds a lot lighter already. The cross section of 3/32" should be about 56% of 1/8" cord. I've never weighed the two, but it might be worth the weight savings to some...

If I were to do one thing differently it would be to make the quilt a little wider at the top...38, maybe 40 inches. It's perfect when I'm still and centered, but I can get off center a little when I roll on my side, and a little more on the sides will make coverage less sensitive to that.
Grizz

Thank you, I will keep that in mind and make my quilt a little wider. Mine will be only 50" long, I think.

Would you make the baffles a little wider in the critical area to avoid CBS?

[GrizzlyAdams]

...
Would you make the baffles a little wider in the critical area to avoid CBS?

Undecided. Some of the discussion suggests that the cause of CBS may not necessarily be needing more insulation there...on the one hand the extra material/down to do that probably is not all that much, on the other hand it definitely adds another dimension to the warping here---the outer shell just became 3D. I should probably give it a try just for the fun of it.

Or you can, and tell us how it's done

Grizz

[Shug]

In the times I've been out with the quilt...20 degrees---toasty warm.
-2 degrees---cold butt syndrome, otherwise OK. -2 degrees with assist from downmat...heavenly.

Sweet stuff Grizz and I enjoyed my math lesson this morning. When I make my next full length UQ I will find a way (Hack for sure) to make sure I have more loft in that buttocks area. At around 5º to anything below 0º I find for guaranteed warmth in that area a pad, whether full or just a small piece, makes the difference.
Been playing with the 1/2 UQ with my down vest in conjunction (laying it very flat between hammock and uq) in this cold here in MN along with a blue ccf and a covered GG pad slid from butt to feet. Working well so far and I will continue to test.
Brilliant job on that there project!!!
Shug

[Shug]

yeah, a video would be more along the lines of "Bloopers", or "America's Funniest Boneheaded Sewing Errors".
It would give Shug a run for his money, for sure. Grizz

Don't make me do a serious video!!! BTW, what money$$$$?
Shug the Wanna-Be Quant

[Catavarie]

So I've learned that when Grizz posts a link to follow it and read it in full. Now my head hurts and I feel as if I need to go back to school as I think all the math in the OP went completely over my head.

Grizz may not be an evil genius, but he's certainly a genius in my book.

[turnerminator]

Brilliant Grizz!

Fantastic write up and I like the math.

This will be a big help to a lot of people.

[Ears]

hey grizz, just read this post, thats a very fine way to tackle such a project. i will definitely be using this method. hopefully even to a degree of your success. very nice.

[WV]

Thanks to Catavarie for revisiting this thread, in particular for the following line of thought.

Would you make the baffles a little wider in the critical area to avoid CBS?

Undecided. Some of the discussion suggests that the cause of CBS may not necessarily be needing more insulation there...

...on the one hand the extra material/down to do that (make the baffles a little wider) probably is not all that much, on the other hand it definitely adds another dimension to the warping here---the outer shell just became 3D. I should probably give it a try just for the fun of it.

Sweet stuff Grizz, and I enjoyed my math lesson this morning. When I make my next full length UQ I will find a way (Hack for sure) to make sure I have more loft in that buttocks area. At around 5º to anything below 0º I find for guaranteed warmth in that area a pad, whether full or just a small piece, makes the difference.
Been playing with the 1/2 UQ with my down vest in conjunction (laying it very flat between hammock and uq) in this cold here in MN along with a blue ccf and a covered GG pad slid from butt to feet. Working well so far and I will continue to test.

This is all most interesting. Why do you think there is CBS in the first place? I recall seeing a low-angle side photo of someone lying in a bridge hammock. and noting that the occupant's butt was clearly lower than the rest of him, so fabric stretch clearly creates a partial banana posture which would tend to make an insulating layer thinner in that crucial area. I submit that it's not just the outer shell of the underquilt that warps in two directions. The inner shell needs to be 3D, too. Griz, is that what you were referring to when you speculated about the cause of CBS not being just a need for more insulation - rather a change in the volume it's contained in as well? Somebody should figure out a way to measure the pressures that various parts of the body exert on a hammock's fabric, notably heels, shoulders, head, and butt. Then calculate the variable densities of insulating materials or shape of containments thereof needed to compensate. I doubt that I would have the mental stamina to read such equations if they existed, so thank heavens for the experimental method of our finer researchers, who juggle materials (thanks, Shug) in search of uniform bodily warmth and comfort.
What is the perfect hammock insulating system?

[MacEntyre]

Thanks, Grizz! Enjoyed the math... simple but elegantly presented. Good job of generalizing the solution.

What is the perfect hammock insulating system?

Light weight, toasty and inexpensive!

[BrianWillan]

Light weight, toasty and inexpensive!

Pick any 2.

Cheers

Brian