UnderQuilt Build - Dutchware Raffle Project

[Mcdoc]

Hello!
I had the luck-o-the Irish the other week and won the raffle contest by Dutch to design/build an under quilt. Reference this thread. The premise was that you design a "fantasy" quilt using materials from his site, and the drawn winner wins those materials to build a DIY quilt. Cool idea, and a very generous way to support HF and generate interest in DIY builds. I was researching a possible quilt project at the time, and went ahead and threw my hat in the ring with a no-holds-barred design:

It’ll be a 3-season quilt because that seems the most versatile, and if you ever get cold you are not a wimp, but you can just say the ‘season’ is over and you need to buy more gear! It’ll be down, because down is packable, light, and awesome. It will be full-length 72”x48”. It will be baffle-box construction, but will have a ton of baffles. Not 5 or 6 big droopy baffles, but a bajillion smaller ones- like a puffy down coat. I’m thinking 1.5 inch height per baffle, spaced 3-4 inches apart. Yes, it will take forever to sew, and probably be a pain to stuff, and will be slightly heavier with a bunch more baffles, but that’s what I haven’t seen made before, and how I’m going to make mine. And they will be horizontal, longitudinal, DIAGONAL/ SPIRAL. Double-differential with diagonal baffles- there’s the challenge! Outside color will be two-tone: charcoal grey and forest green Argon67. Maybe a big center stripe going the opposite direction of the baffles (again, because I haven’t seen it done before). Black Argon67 Taffeta on the inside. Dual suspension with 3/32 shockcord and ridgeline quilt hooks.

Materials:
3 yds black Argon 67 Taffeta
3 yds forest green Argon67
1yd charcoal grey Argon67
80 ft of 1.5in no see um baffle material
12oz 850 goose down
4 mini cord locks
4 lineloc3s
1 white and 1 black ridgeline quilt hooks.
2 aluminum quilt hooks
25 ft 3/32” shockcord
1 spool black gutterman polyester thread
1 yd black argon sil

It might seem non-traditional, and a little odd for two reasons: 1) I've never made or even used an under quilt before, and 2) I doubted that I had a chance to win and would actually have to make it.

Well, now it's on! Like many other folks here, I am a DIY maniac- and revel in the satisfaction of having made something yourself. There is a certain allure to the challenge of learning a new skill or technique, the freedom to innovate and test original ideas, the risk of failure, and the reward of a final product that you wouldn’t have any other way. A big part of it for me is the process itself, and I am at my best when I am exercising creativity and problem-solving skills. I don’t really care about making things quickly, or easiest, or even cheaply. And often the final product is not even well-made, but an amateur hack that works just fine. The biggest value is the learning and personal betterment that comes out of it: later projects that use those skills will be dynamite! Even better is the online community who post build logs and discussions to share those things with others.

I have a little sewing experience, but am new to DIY gear.
Only a few weeks ago I completed my first ever functional sewing project, a tarp based on Blackbishop’s design with snakeskins , tarp flyz, tensioned guylines, and a stuff sack. I had a lot of fun and love the result. I have drank the kool-aid, so to speak, of the DIY gear group.

So here starts the build thread. Please read, comment, help me with things I could do better, and improve on these ideas for your own project.

-k

[Mcdoc]

So it starts with an idea, and then a sketch on a napkin:
napkin.jpg

I had this idea for spiraled baffles that would wrap around you and stretch in several directions. It looks awesome in my head.
Mostly it is for aesthetic appeal, but might have some neat physical properties to it as well.

[A lot of these ideas are not original to me, and you can easily loose a few hours of time reading the genius that is some of the really old archives on this forum. *Any references I link to are by no means a comprehensive list- only bits and pieces of things I've stumbled upon.]

I'm certainly not the first person to question why most baffle designs go lengthwise. SteelToe is certainly good at thinking outside-of-the-box.
This is an interesting way of looking at getting insulation to the important places and cutting weight.
Te-wa has used diagonal baffles in quilts.
and Wilderness Logics sells under quilts with diagonal baffles.

So then the napkin drawings became slightly more tangible as a model in sketch up:
curves.jpg

Another design element is how to have the quilt snug against your backside without compressing the down. It seems the best way to do this so far has been to use a differential cut.
I have been inspired, though, by the concept of stretch-baffles.

thru-hiker used a single piece of elastic diagonally to apply some snug [no, not shug].
VictoriaGuy started questioning it from looking at the MontBell/Sierra Designs sleeping bags with stretch baffles.
te-wa sells quilts with stretch baffles.

Ive read ideas of using stretch material for baffles, or making the entire inner-layer of the quilt out of a stretch material, but haven't seen much for prototypes. My thought is that you want something stretchy enough to keep the quilt against the hammock, but no so tight that you're lying on tight strands of elastic that become uncomfortable.

I thought the solution might be in using something of relatively mild stretch: elastic thread. Reading this post by someone familiar with other sewing techniques made me look further at the concept of "shirring".

[Mcdoc]

Shirring is using elastic thread in even rows of stitching to make the fabric bunch up.
ScottieVonPorkchop has used it instead of darts to match the edge-length on a differential quilt. But my thoughts lean towards the technique used in dressmaking.
shirring4.jpg

Could this be applied to an under quilt? It would snug the quilt against the bottom of the hammock, but would only involve the inner layer and wouldn't compress the down. Would it be too stretchy though, and feel uncomfortable to lay on?

I stopped by the fabric store on my way home from work and threw together some quick tests from sil scraps I had leftover from my tarp.
SHIRFLAT.jpg
SHIRCRUNCH.jpg

These are using a roughly 1sq ft piece of silnylon with 3/4"grossgain binding the edges that would represent the suspension channels.
I was using a freehand diagonal curve with stitching spaced 1.5" apart. The thought was originally that I would use the elastic thread to attach the baffles to the inner liner. It has a very mild stretch, and actually pulls the edges into somewhat of an "asymmetrical" parallelogram.

[Mcdoc]

Next I started to get into some serious drafting and trying to come up with a working pattern. I realized that while it looked awesome, my curved baffle design would be very difficult, if not impossible, to apply to a single piece of shell material with a differential cut outside of the liner. It took some serious thinking in 3-d to realize this won't work. You could cut out each baffle segment of shell material individually, but that just isn't practical and would bring a lot of extra weight to the quilt with all the connecting seams.

dang.

So baffles will have to be straight to make a differential shape without using some serious modeling software. I'd like to keep the diagonal concept, though, as it is somewhat rare, and might actually make sense based on a diagonal lay in the hammock. instead of curving the differential straight from side-to-side, It will be canted to match the diagonal direction of the baffles (Body laying lengthwise with the baffles and the major curve perpendicular to the baffle direction.)

So my sketchup file is progressing to something more workable.
sketchup.png

Without the curves, though, the shirring (stretch) won't work by pulling along the axis of the baffles. It needs to be perpendicular: pulling from suspension channel to suspension channel. The solution is to independently shirr the inner quilt layer crosswise, and then attached the baffles normally lengthwise.
liner layout.png

Bingo. Except sewing the baffles on while it is trying to scrunch up is going to be difficult.

[12trysomething]

I am sitting in my seat and have firmly put my seatbelt on for this one. I am subscribed to this. Thanks for the start.

[ShooTa]

subscribed -
your problem MIGHT be possibly fixed by first finnishing the bottom layer and the baffles
THEN and this is where it would be a PITA but begin sewing from the centre out which would then mean that the stretch would be less of an issue .

OR you could somehow have the stretch ONLY on the baffles in certain places

OR you add the stretch after completion in bands afterwards (it would be alot more ugly) but this would deform your baffles somewhat.

could you have sewn channels that you could run the stretch through afterwards?

[Eidson]

First off, congratulations! After looking at your other diy jobs, if anyone had to win other than me ;-), I'd hoped you would and we'd all get to watch you through the process.

I'll be eagerly following your thread and am excited to see your progress.

[Deathstar77]

*wipes drool off of floor*

[Mcdoc]

subscribed -
your problem MIGHT be possibly fixed by first finnishing the bottom layer and the baffles
THEN and this is where it would be a PITA but begin sewing from the centre out which would then mean that the stretch would be less of an issue .

OR you could somehow have the stretch ONLY on the baffles in certain places

OR you add the stretch after completion in bands afterwards (it would be alot more ugly) but this would deform your baffles somewhat.

could you have sewn channels that you could run the stretch through afterwards?

Yes, the plan is to make the 'bathtub' first with the outer shell and baffles, and then attach the 'lid' of the already shirred inner layer.

Thats a good idea- sewing baffles to the inner layer from the center outwards to mitigate some of the scrunch. With the spacing of the shirring stitches 1.5" apart, it ends up being a very mild stretch, and I was just going to try and stretch it as flat as I could while sewing the baffles on. It probably won't be very straight seams either way, but it's on the inside layer (against hammock) of the quilt so it doesn't really matter.
I had thought that with the shirring technique there are a lot of variables left undefined that can possibly be adjusted. You can add prescribed amounts of stretch by varying the spacing between shirr lines, and also control the location and direction of the stretch to be anywhere you want. That was one of the thoughts when I was considering the 'spiral baffle' design, to have a relatively flat lay where your body is, but have the sides of the quilt stretch up around your feet and your shoulders. It still looks cool in my head!

One of the things I can't really change is the amount of stretch present. I would think the optimal amount is whatever pulls the weight of the quilt up against the hammock without being able to feel the elastic lines. No way to calculate that other than trial and error success. The 1.5" spacing is just a guess right now based on my 1sq ft test. I have thought about trying to make a larger test piece to see what happens. Also- it worked well with sil, but I'm using Argon67 taffeta which might not act the same way.

[Mcdoc]

I worked through catsplat's spreadsheet calculator a few times and decided that this can save a lot of math that you have to do anyway. Awesome! The trouble, however, is that I want the baffles tilted on the diagonal, along with the major differential curve. I'm not sure if I can explain it that well, but my solution is to use the sketch up model to fit my 74x44 inch quilt into a "ghost" rectangle with edges parallel to the baffles. That way I can put it into the calculator and pull baffle/shell dimensions/loft/etc. This is one of those things where a picture probably explains it best:
angled rectangle.png

After I use the calculator, I can make a scale model of the 'ghost' rectangle shell (using the output shell width), and then work backwards in sketchup to get the dimensions of the shell that I need for my actual quilt shell. I'm sure there is an easier way to do this, but this is the first thing I came up with that doesn't involve a ton of paper-and-pencil mathematics. I would mess that up for sure. Interestingly, the (flat) shell piece comes out to be a wicked parallelogram:
ghost shell.png

It looked wrong to me at first, but I think it is correct. This is a model of the shell laid flat. in actuality, each baffle will loft to form a half-cylinder which brings the whole thing back to a rectangle shape. Note that I still have to make allowances for the "sides of the bathtub" and channels/seams on the ends.

So my original idea called for two colors of shell material. Dutch was out of grey argon67 so I went with forest green and saddle brown. I think that what I will do is swap in brown argon for the green along two of the baffle chambers. This is illustrated in the picture above, but the colors are not accurate. So the whole shell will be cut out of 5 pieces of argon: 3 green pieces and 2 skinny brown strips. Any other ideas of a cool pattern that can be cut-and-stitched? I had thought about a big X of brown in the center or something.
It will be easier to keep the seams in line with the baffles, though, and it should highlight the diagonal pattern of baffles when looking at it from either side. It's not the spiral shape I had originally thought of, but I have to let that one go for now.


Of course the 'ghost' rectangle dimension that I put into the calculator make it think that I'm making an 7-foot long quilt, so the estimated weight is a little off! If I use the same size/spacing/loft of baffles assuming a straight baffle design, I get this:
output.png

Not bad: 30% overstuff using a total of 11oz of 850down will estimate a weight of 16.8oz and temp rating of 21deg! These are estimations, and I know it will be heavier because of the suspension, shirring, and gram-gnomes that somehow make their way into the final product, but that is right about on par with my design goal for a 3-season full-length underquilt.