MYOG Quilt Overstuff vs Baffle height??

[Joshua L]

I’m working on my first quilt. I have done a lot of work and have the final width and length. What I am now stuck on is baffle height. I know I want a 20 something degree quilt. I have 12 oz of 800 down with gives me two options. 1 go with 2.5″ baffles with zero overfill or 2 go with a 2.2″ baffle with a 14% over fill. According to Zpacks down loft chart 2.2″ should get me down to 20 degrees F. I am guessing that they will both loft up the same but wanted others opinions on it. I guess I also have a third option of making a 2″ baffle which would be a 25 degree using the same chart and use the extra down for a quilt plug or something else. Let me know what you think. I would be using this for so cal and Sierras. I am a warm sleeper.  Thanks

[David Gardner]

My best guess is that more baffle height will give more warmth than overfill, and will drape better to minimize drafts.

[Lance M]

The fill rating for down is measured after careful drying and fluffing.  Real world fill power is much less.  Overfill is required to compensate for the loss of fill power due to humidity, dirt and compression.  You will have cold spots from loss of loft unless you overfill.  In my experience (making and using four quilts), 14% overfill is a bare minimum.  There is a reason Zpacks (30%), Enlightened Equipment and others overstuff their quilts and bags.

Hope this helps,

-Lance

[Jerry Adams]

I’d do 30% over fill.  2 inch baffles would give you 20% which would probably be good enough.

Otherwise, the down tends to shift to the side leaving places with no down thus cold, compounded by what was said above

If you compress down, theoretically you still get added warmth.  If you add 20% more down, it will add half as much warmth as if it was fully lofted.  So, by reducing the loft from 2.5 inches to 2 inches, you lose about 10% of your warmth.  But because the down doesn’t shift leaving bare spots, it’s worth it.

 

[Joshua L]

Thank you for your help. I think I will go with the 2 inch baffles. That will get my overfill up to 25% and still be close to what I am shooting for.

[Tim Marshall]

start with 2″ baffles, finished height should be ~1.5″

-Tim

[Joshua L]

Tim when I referred to 2″ baffles i was talking about finished baffle height. I was intending for raw baffles to be cut to 2.5″.

[Michael L]

It depends somewhat on your baffle design and spacing and also your intended use (i.e. hammock or ground, I’m guessing ground) but in general I agree with Tim, go with 1.5″ finished height. If you don’t have enough down control you will be disappointed with cold spots. It will still loft up higher between the baffles so the down won’t really be compressed, it just won’t be completely even in thickness but in my experience it’s well worth it for the down to stay where you need it.

What is your baffle design?

[Tim Marshall]

Joshua,

.5″ bellow loft is pretty standard. However I feel you get better down control without overstuffing with baffles 1″ bellow loft. I consider overstuff based on desired loft, not baffle height.

-Tim

[Joshua L]

Thanks Tim Marshall. I understand now. I am trying to maximize the 12 oz of down that I have. The quilt is 3831 square inches. That is 7662 cubic inches with a 2 inch thickness with the 800 down its 9.58oz before overfill. So with 12 oz down that would be 25% overfill. So do I use 1.5″ or 2″ baffles? I was under the impression that I should use 2″ baffles and the overfill would keep the down in place. Now maybe use1.5″?

[Joshua L]

Michael I was going to use width wise  baffles. I considered karo step but the width baffles seem easier. Which would you recommend? My sewing skills are limited, mostly just fixing clothing seams that have come undone and such.

[Michael L]

I’ve personally found lengthwise baffles to be more effective at keeping the down in place than width wise baffles as they prevent the down shifting to the edge if you turn in the night. I had problems with the down thinning out in the center during the night even with 70% overfill (width wise baffles, 1.5″ finished baffle height and 5″ baffle spacing). The quilt is still alright and I used it for over 100 nights but it wasn’t the most effective use of materials. I’ve found subsequent quilts with lengthwise baffles to be much more effective.

If you sleep very still or just want to use the quilt in a hammock then it probably doesn’t matter so much but that was my experience.

My recommendation would be to do lengthwise baffles with 1.5″ finished baffle height and approx. 5″ baffle spacing. Take your time and I’m sure you will come out with a wonderful quilt!

[James Marco]

Yes, Tim is pretty good with his quilts. He is recommending a 5″ baffle width and a 1.5″ baffle height. I believe that you will find that the “average” finished thickness will be roughly 2-1/4″ when dry and fluffed (1.5+3.0)/2. Roughly this corresponds to about a 25-30degree quilt.

A somewhat better job can be done by narrowing the baffle width to around 4″ and opening baffle height to 2″. This will reduce the down expansion of the baffle, so you open the baffle height up a bit. This will result in a more even distribution of the down (reducing cold spots.) Expansion of the bellows will also be reduced. So, you trade a deeper center loft for more even expansion of the down fill. It will add a little weight, maybe a half ounce to an ounce.

Follow Tim’s logic and design for baffle placement: vertical/horizontal placement for both Revelation’s/Enigma’s. While vertical baffles keep down in place one way (side to side,) they increase the length of the baffle column allowing more shifting (carrying and washing.) And, turning the corner will result in a larger baffles when measured by comparing loft to baffle, especially diagonally (a very minor issue with the Revelation I use, it is warm enough with no real complaints.) With the turn at the lower legs, often the most restless portion of a person, he also reduces the column length for every vertical baffle.

I would quibble with this (besides for symetric looks.) By making the baffle height 2″ and going with a 4″ spacing, you can then go for the ideal compromise of a 45degree baffle arrangement, placing the larger “corner” baffles (where down will tend to accumulate with carrying/proper maintenance) directly in the center, where it will be the most effective covering you, regardless of your sleeping position (side, back or stomach.) For production purposes, I doubt this would be the best because there are more baffles to sew, a more complicated sewing pattern and more pieces to cut out. For doing one as a custom job, I would do it. A very minor point, though, overall durability will also increase slightly. But, so would weight.

[Joshua L]

If I use a vertical baffle how wide would I need to cut the fabric to end up with a finished width of 54″?

[James Marco]

Calculate the circumference of the arc where you sleep. Note that this will taper down towards your feet. Usually the foot box, and/and or the foot area is sewn, but may not be. Sometimes it is just Pull Corded allowing you to ventilate the foot box area, and, open it out flat. Sometimes there is a full round or oval shaped foot area that is sewn in and extends to something under your knees. Sometimes there is a zipper to extend the enclosed area to just above your knees.

Pi x Diameter = Circumference (or 2 x Pi x Radius) Insure the outer is calculated using your thickness of loft, and, the inner is calculated using your nominal width. Note that a half circle is used as an approximation since for top quilts they don’t wrap around you. However, when you make the foot sewn in, then you will need to calculate based on a full circle for the foot box. Then about 8-12″ up, taper that width to your shoulder width. I never deal with numbers so here is a chance to test your math skills!

I personally believe that 54″ is too narrow in a 20F quilt, unless you sleep still. It will leak warm air with most movements. Not bad at 30F, but can be quite bad at the 20F limit. I toss and turn a bit, so I went wider (58″.) Knowing I can open the foot box at 30-40F but when cinched tight, it will supply some extra down for my feet at ~20F. I have diabetes and worry about freezing my toes because I have poor feeling in them. Note that at 20F and UL gear, that means all my cloths, including two pair of socks(hiking and sleeping.) I should never hit that temp but sometimes it happens…

[Joshua L]

James I was referring to the shrinkage from adding the down with vertical baffles. I was assuming that due to the bulging between baffles there would be some shrinkage. I took a 1.5″ comforter and pinned it into the shape of my planned quilt. I am mostly at side sleeper but also sleep on my back or belly.  It seemed big enough but I have  never used a quilt at 20* I  was planning on using a draw string closure for the footbox

[R]

The angle between the vertical baffle and the outer (or inner) lining of the quilt on either side of it (creating adjacent cells) is 120d. Right at the baffle seem it’s a perfectly even Y shape.

That means a fully stuffed baffle forms a 120d section of a circle. Take your baffle width, 4 or 5 inches, and you can work out the radius of the resulting circle and the effective width of your baffle. Compare that to your design baffle width and you arrive at your stuffing shrinkage.

I think it’s only around 3%, or about 1.5″.

You should do the math yourself to be sure, and learn a bit along the way, but I’m pretty sure you can basically ignore it.

Disclaimer: I haven’t actually made a baffled quilt.

[Michael L]

You won’t need to add too much width to account for the fabric bulging. It’s much less with the baffle specs we’re talking about compared to a sewn through quilt for example. I’d keep things simple and go with a 55″ design width with 5″ baffle spacing.

Quilt sizing is a personal thing in the end. 54″ is more than sufficient for me even below freezing (coldest temp I’ve been exposed to is about 20F) and I do switch between both sides and back during the night. You won’t really know your preference until you’ve got some experience but I’d say 54″ is a good place to start.

[James Marco]

Both the inner and outer layers will bellows out a bit. Unfortunately, every baffle will also need to be aligned along with this, making positioning a but difficult. (Somewhere around 1/8-5/32″.)

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