Staggered sew lines UQ

**Bradley** · 09-23-2010, 00:27

Just thinking and wondering:

I mostly see UQ sewn with what appears to be tubes from side to side . . .

and I thought that where it is sewn and thin it would likely pass cold . . .

But if the UQ had a layer of RSN between the tubes
and the tubes were staggered
it would have a better insulating value

Yes / No ???

**samiam2714** · 09-23-2010, 00:31

I was thinking about this when I was planning my UQ. Nice Diagram.

I don't see Why it wouldn't work.

**Kaminari** · 09-23-2010, 00:41

Hmm... very nifty. I would have to guess it would work, assuming the center piece of ripstop was not able to be pulled tight from the sides, thereby flattening the insulation. I bet you would have to make the "tubes" a little extra loose.

**dejoha** · 09-23-2010, 01:57

Most under 3 season quilts are not sewn through as you illustrate. They have chambers and walls inside, much like a ship with bulkheads. I think it is common to use netting for the walls or even light ripstop. The design you illustrate where you sew or quilt through the fabric is more common with summer quilts.

**MAD777** · 09-23-2010, 05:53

I had the same thought before I started making my own down quilts. However, now that I have a bit of experience behind me, I would not recommend it. The reason has nothing to do with the final performance of the quilt, I think it would insulate efficiently.

But, this type of construction is very difficult in an unforeseen way, at least for me. Here I will attempt to explain the challenge...

Silnylon is very slippery. There is virtually no friction between the layers. You will be sewing two layers together, multiple times, in the middle of big, opaque sheets of this stuff. while you have no "line of sight" to the bottom layer.

Now here is the kicker. With standard sewn thru quilts, the top & bottm baffle spacing is the same. So, you just need to keep both the top & bottom layers pulled tight from the previous seam, and with a bit of luck, all should line up.

In your construction, which I have tried, the seam spacing in the top layer and, in this case, in the middle layer would be different. The spacing on the top (and bottom) would be larger than the middle layer to allow the top and bottom to puff up.

This means that you can't pull the two layers tight while sewing. You will need to hold the two layers such that the seams will line up as intended, all the while, you cannot see through the top layer and they will slide around as freely as two warm sticks of butter!

At least that was my experience, so I have abandoned this type of construction for baffles made of netting that allows me to see what I'm doing.

**Bradley** · 09-23-2010, 06:43

Originally Posted by MAD777

But, this type of construction is very difficult . . .
This means that you can't pull the two layers tight while sewing.
You will need to hold the two layers such that the seams will line up as intended,

Don't you pin your material together so it stays in place while sewing . . .

It's how my Mama use to do it.

**Big Jim Mac** · 09-23-2010, 06:54

Mama put it in a quilt frame though! I've been thinking about doing that, my mom has a frame still set up but can't use it due to arthritis. Figure if I get the whole family gathered around the frame working on it I could have one ready for the 2012 season LOL.

**KerMegan** · 09-23-2010, 07:01

you could start a whole new tradition at reunions! Family gear making..

I think I have see this, many many moons ago-circa 1970-88) Sleeping bags were done in sewn thru, offset-(2 layers arranged so the sewing did not line up,) baffled, and slant baffled.; depending on how much cold they were intended to resist.

**Jsaults** · 09-23-2010, 07:10

Look at your second diagram, and envision the bottom layer of fabric shifting to the left. But it would use extra fabric to obtain the loft, and would probably allow down shift. I will do a quick graphic when I return to my desk later this morning.

Jim

**MAD777** · 09-23-2010, 07:16

Originally Posted by Bradley

Don't you pin your material together so it stays in place while sewing . . .

Yes, I pinned it, but the slick materials still wandered between pins (which were only about 4" apart) making for some wavy stitch lines. The problem would be most pronounced when, due to Murphy's Law, adjacent stitch lines would migrate toward one another at the same spot. This would frustatingly make one baffle space smaller and the adjacent one larger.

The quilt still "works" but, I didn't get that satifying feeling of accomplishment (not that my goal is perfection, just function). Fortunately, it was a "summer" weight quilt, so I won't be pushing any limits with it on some Arctic expedition