Delta Karo Step?

[Ryan Smith]

Ha. That's awesome. I haven't made a quilt in a while now, it's all been cuben shelters lately. Both are a lot of fun(and work), but when they're done it's a great feeling to see it all come together.

Ryan

[J-L]

Adam, what about using tulle for your baffles? I picked up some stuff at Joanne's (was labeled as "nylon tulle") and it seems to weight about 0.22 – 0.25 oz per square yard.

I used some of this material to turn the rear half of a Megalight into a fully-enclosed bug-free area for my dog and I. It's held up with no tears so far despite my dog's best efforts, but it's only at about 15 nights. I'm using more tulle now to make an inner tent for my Argon hex pyramid tarp.

People seem to say it's not durable, but I think it's fine. It is kind of annoying to sew and dimension out

[Adam Kilpatrick]

Tulle is definitely an option, though so far I've based calcs on .33 cuben for the strength.

Seeing as though you already know a source, any chance I could get you to provide a link for me? I can try it out with some tests, and I can always pick and choose where I use it.

[J-L]

I think this is the stuff I bought in the store:

http://www.joann.com/matte-tulle/10449056.html

Gotta love the description!

[Adam Kilpatrick]

Awesome John! I've searched for Tulle and seen lots of varieties in local haberdasheries here in Adelaide, but its hard to know how much each one weighs without taking the plunge on it so I can cut it up. Not the normal priority of Tulle retailers (weirdos).

I'll be sure to pick up some extra; I'll practise on a Tutu for my little girl (almost 17months, she'll love it) :-)

[Roger Caffin]

Lots of hits on google, nothing I could find about the origin of the name 'karo step'. Anyone got any idea?

Cheers

[Adam Kilpatrick]

Hey Ryan

Yep, got some ideas off Aaron's threads from over the years including that "Cup Quilt". Actually I realised a couple of days ago that my idea for doing a lightly filled sewn through edge baffle (its tucked under mostly so doesn't need to be full loft anyway) he has done before, so perhaps my head is screwed on correctly! I will do this edge baffle in cuben though as the vapour barrier effect won't be an issue for me there, also bonus the down won't get wet if it drapes off my pad and/or groundsheet etc.

At the moment I think the calcs have total down around 6oz, fabric etc around 4oz give or take either way (don't have it on this computer).

Actually I just wanted it pretty light, just to the right size and to have some neat features on it to work with my sleeping style, shelter etc. I was going to be happy with around 11-12-13oz. But then your comments on your quilt about a shorter quilt approaching ten ounces sparked my interest. So I thought I'd do a good job of theoretical calcs in a spreadsheet, and it definitely looks possible so far. I've even included notions like a snap, neck drawcord, tiny toggle, etc. Will double check it all when I convert it over to metric system (will build in metric as its just easier for us). Then will be interesting to see discrepancies in practice! Hopefully there isn't something I've missed.

Its interesting though, when trying to push weight down this far, sometimes see stuff on forums (and really nothing wrong with that at all) like people say, oh baffles don't weigh much, just use noseeum instead of nano or nano instead of cuben, etc, or this fabric is only .1 oz heavier than this one per yard. Well, if I mess with the spreadsheet, I can see pretty clearly how all these little "so close it doesn't matters" adds to grams here and there which eventually turns what could have been maybe a 10oz quilt into a 13, 14 or 15oz quilt! Its not hard to blow it out on slight fabric weight differences. I want this quilt to last me a while (unless the bug really bites and I build futher iterations), so a couple of ounces I think is worth the planning and extra construction effort (and extra material cost) to me. It could be a thousand days on the trail or on my bike times that two ounces. That's a lot of energy :-)

Cheers

[R]

Roger,

Taking a step back, my motivation here is to see if what folks have been doing can't be done better. People seem to be making karos. Initially I sought weight reduction. When I ran the numbers on delta patterns, the weight savings was at most half an ounce, but the unexpected bonus was a substantial reduction in baffle count. The continuous zig-zag is a further step in reducing the effort to produce something that behaves like a karo.

I don't think every one fully grasps the zig-zag concept: make (almost) closed cells because it's simpler; use a highly permeable material so you still get the down mobility of a karo. The benefit isn't weight, it's ease of assembly to realize the mobility aspects of karo.

That said…

John,

So *that's* what tulle is! I keep seeing the term but hadn't gotten around to looking up what it actually is. If that is weighing in at 1/4 oz/sq-yd then the Russian netting *has* to be in the same range if not lower. *IF* the netting is .15 oz (perhaps optimistic), then it will amount to about the same baffle weight as a .3 cuben karo – and be easier to assemble at fraction of the cost.

Adam,

I think every one would be better served if you start a new thread for you current quilt project. This thread has all been speculation on new designs. Once I get the time and materials for some experimentation, I'll start a new thread for what ever prototypes and results I come up with. But I am very curious to see how your project is shaping up!

On the note of prototypes, it occurred to me that a great way to see how different designs loft up is to use this plastic painter's drop cloth, make all the seams with packing tape and then point a hair dryer in to it. This won't tell you how down might move, but it will show you how it bulges when fully stuffed. This could also be used to verify a differential cut to see if it forms the arc you expect.

[R]

Adam,

I've been considering making the shell out of cuben, but putting an 18" wide strip of Argon (.67oz) up the middle, top and bottom. This kills the vapor barrier factor but still lets you use mostly (~2/3) cuben. Saves you ~.6oz vs all Argon if you use .51oz cuben, and 1.2oz for .34oz cuben (based on a 72/54/42 half taper quilt). A .34 cuben / Argon shell like this would tip the scales at just 2.5oz before hardware and baffles.

[Adam Kilpatrick]

Rene, my apologies for creating thread drift.

I am definitely interested in non perpendicular/square karos for my quilt.

How about Trapezium Karo baffles? Most people make tapered quilts. Depending on where you want down control, it could make sense to keep the baffles parallel with the edge of the quilt. This creates a trapezium in the middle if you have an odd number of baffles and make them all Parallel.

[Author]

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