View Full Version : Why 130% overfill?
theperson91
09-15-2016, 10:27
I was just wondering why each chamber in the under quilts is filled to 130% capacity? This appears to add a large amount weight to UGQ under quilts versus quilts from other manufacturers. Does this add warmth? Or is it more of a durability thing in case some feathers get oily? Thanks for any information!
Caminante
09-15-2016, 10:31
I can't speak to UGQ's philosophy (thought they offered options on overstuff), but I overstuffed my DIY quilt by 25% for 3 reasons:
1. Loss of down over time, a small amount of loss will happen even with calendered fabrics.
2. Loss of loft over time - also inevitable with use and age.
3. Lofts faster.
hutzelbein
09-16-2016, 04:36
I'll add this: more down means that it doesn't move around as much. It prevents that some spots are almost empty, while the down builds up in another area.
Those are all good reasons for more down but the number one reason is fill power is measured in a perfect lab environment, down is conditioned for 24hrs, and has no restraining materials i.e. fabrics to prevent full lofting. Other vendors also overfill from 120-130% even if they do not indicate it, it is industry practice. We choose to use more down than many other.
As for comparing wgts here are several 44" wide 20* Full UQ
22.0 oz HG w/ 12 oz 850
24.7 oz Loco w/ 15 oz 850 (80" long)
22.85 oz UGQ w/ 13.64 oz 850
If we used 12 oz of down we'd be 21.21 oz, lightest of the bunch...
Caminante
09-16-2016, 07:04
Good info, Paul, thanks.
theperson91
09-16-2016, 09:12
Thanks for the clarification!
Secondmouse
09-16-2016, 13:01
dumb question - how do you know what is the "correct" amount of down and what is "overfill"?..
dumb question - how do you know what is the "correct" amount of down and what is "overfill"?..
You take the fill power, which is how many cubic inches of down a given fp should fill, then calculate the volume of your quilt/sleeping bag. Add overstuff if desired.
Caminante
09-16-2016, 15:22
dumb question - how do you know what is the "correct" amount of down and what is "overfill"?..
Fill power tells you how much volume in inches cubed an ounce of down will fill. So one ounce of 800FP down would fill 800 in^3. If you have a quilt that is 44" x 64" x 2", then it is 5,632 in^3 and would theoretically need 5,632/800 = 7 oz of 800FP down to fill it up. However, for the reasons stated above, it is desirable to "overstuff" the down by some percentage to move from theory to real world. In this example, if you wanted 30% overstuff, you would actually use 7 * 1.3 = 9.2 oz of down to fill the quilt.
dakotaross
09-16-2016, 15:28
As for comparing wgts here are several 44" wide 20* Full UQ
22.0 oz HG w/ 12 oz 850
24.7 oz Loco w/ 15 oz 850 (80" long)
22.85 oz UGQ w/ 13.64 oz 850
If we used 12 oz of down we'd be 21.21 oz, lightest of the bunch...
Doesn't the HG shell have less volume due to the way it tapers, therefore, requiring less down?
warbonnetguy
09-16-2016, 15:58
More specifically, fill power states how much volume an oz of down lofts to in a certain size and shape container while a certain sized weight is placed on top of it. It doesn't have anything to do with how much should be used in the filling process. You'd never want to use say one ounce of down per 850 cubic inches of quilt volume, that is nowhere near enough. I dont think any MFG uses those numbers to determine fill amount. FWIW, one ounce of 850FP down takes up alot more than 850 cu. inches...that 850 rating is when it is partially compressed by the weight.
Down density (how tightly the down is packed in) is as important as the amount used or the baffle height. Generally you want to pack enough in there so that you aren;'t always dealing with dead spots from alot of down shifting. If it's filled well it wont shift that much and if it does shift it wont leave a dead spot in it's place.
Secondmouse
09-16-2016, 16:34
You take the fill power, which is how many cubic inches of down a given fp should fill, then calculate the volume of your quilt/sleeping bag. Add overstuff if desired.
mmm, I'm not so sure it's as simple as that. I saw a formula once but can't remember where...
Secondmouse
09-16-2016, 16:37
More specifically, fill power states how much volume an oz of down lofts to in a certain size and shape container while a certain sized weight is placed on top of it. It doesn't have anything to do with how much should be used in the filling process. You'd never want to use say one ounce of down per 850 cubic inches of quilt volume, that is nowhere near enough. I dont think any MFG uses those numbers to determine fill amount. FWIW, one ounce of 850FP down takes up alot more than 850 cu. inches...that 850 rating is when it is partially compressed by the weight.
Down density (how tightly the down is packed in) is as important as the amount used or the baffle height. Generally you want to pack enough in there so that you aren;'t always dealing with dead spots from alot of down shifting. If it's filled well it wont shift that much and if it does shift it wont leave a dead spot in it's place.
yeah, I remember a discussion some years ago on the appropriate density and the formula to compute that but I disremember where...