Torso Length Costco Down UQ

[gnomad]

Bumping Hammonkey's question and wondering if we have more data for this design's performance. I have ripped the horizontal seems and gathered the down, but I am wondering too if 6 10" tubes would outperform the 12. There would be less draft from the sewing, but is there enough down to fill the space in 10" baffles?

[m_urbanawiz]

Bumping Hammonkey's question and wondering if we have more data for this design's performance. I have ripped the horizontal seems and gathered the down, but I am wondering too if 6 10" tubes would outperform the 12. There would be less draft from the sewing, but is there enough down to fill the space in 10" baffles?

I haven't tried this mod, but I think 10" tubes would give you too much shifting. I found a fair bit of down shifting to the bottom as it was. Also, a month or two ago when I ran the numbers to estimate the total amount of down in the throw, I ended up with calculations that suggested that it wouldn't loft up much more then with the stock baffle widths.

[Windwaker]

Thank you so much for the instructions. I need to do this to mine and your finished quilt looks great.

[Secondmouse]

I haven't tried this mod, but I think 10" tubes would give you too much shifting. I found a fair bit of down shifting to the bottom as it was. Also, a month or two ago when I ran the numbers to estimate the total amount of down in the throw, I ended up with calculations that suggested that it wouldn't loft up much more then with the stock baffle widths.

this is interesting. where did you find "calculations that suggested that it wouldn't loft up much more then with the stock baffle widths". is this something that you can share?

would these calculations give a prediction on the effect of doubling the amount of down in a single blanket?..

[m_urbanawiz]

this is interesting. where did you find "calculations that suggested that it wouldn't loft up much more then with the stock baffle widths". is this something that you can share?

would these calculations give a prediction on the effect of doubling the amount of down in a single blanket?..

I don't have the calculations anymore. What I did though, was weigh the throw before trimming the shell. I then weighed the part I had trimmed. Based on the weight of the trimmed shell and its square footage, I calculated how much the shell weighed. Once I had a close estimate for the shell weight, I subtracted it from the total weight of the throw to figure out how many ounces of down were in the throw. I then assumed the down was something like 600 fill power (e.g., 1 oz equals 600 cubic inches). I then modeled the remaining baffles as a certain number of equal cylinders to calculate their volume (similar to how one would calculate how much down you need to make a traditional baffled UQ or TQ). The number I came up with was in the neighborhood of the the weight of the down times 600 (I can't remember the exact numbers for the shell weight and my estimate of the fill weight. it was something like a 60/40 split, but I can't remember which way).

Based on simple math, if you double the width of a baffle, you quadruple the amount of down you need to fill the baffle to the same amount. I.e., if you go from 5" baffles to 10" baffles, you go from a 2.5" radius with 6.25 * pi sq in cross sectional area to 5" radius with 25 * pi sq in cross sectional area. That tells me that you end up with baffles that are much emptier, which means much larger cold spots and the down will shift freely within the baffle.

As far as:

would these calculations give a prediction on the effect of doubling the amount of down in a single blanket?..

My memory is that doubling the amount of the down in the quilt would roughly fully loft the baffles. Adding more down beyond that would not help nearly as much, it would simply over stuff the baffles. While some degree of overstuffing is useful, there is quickly diminishing returns after 10% overstuff or so.

My approach effectively doubles the amount of down in each baffle by condensing it into a shorter baffle. I.e., all the down in a 70 x 60 quilt is condensed into a 60x35 quilt (roughly speaking).

[Secondmouse]

I don't have the calculations anymore. What I did though, was weigh the throw before trimming the shell. I then weighed the part I had trimmed. Based on the weight of the trimmed shell and its square footage, I calculated how much the shell weighed. Once I had a close estimate for the shell weight, I subtracted it from the total weight of the throw to figure out how many ounces of down were in the throw. I then assumed the down was something like 600 fill power (e.g., 1 oz equals 600 cubic inches). I then modeled the remaining baffles as a certain number of equal cylinders to calculate their volume (similar to how one would calculate how much down you need to make a traditional baffled UQ or TQ). The number I came up with was in the neighborhood of the the weight of the down times 600 (I can't remember the exact numbers for the shell weight and my estimate of the fill weight. it was something like a 60/40 split, but I can't remember which way).

Based on simple math, if you double the width of a baffle, you quadruple the amount of down you need to fill the baffle to the same amount. I.e., if you go from 5" baffles to 10" baffles, you go from a 2.5" radius with 6.25 * pi sq in cross sectional area to 5" radius with 25 * pi sq in cross sectional area. That tells me that you end up with baffles that are much emptier, which means much larger cold spots and the down will shift freely within the baffle.

As far as:

My memory is that doubling the amount of the down in the quilt would roughly fully loft the baffles. Adding more down beyond that would not help nearly as much, it would simply over stuff the baffles. While some degree of overstuffing is useful, there is quickly diminishing returns after 10% overstuff or so.

My approach effectively doubles the amount of down in each baffle by condensing it into a shorter baffle. I.e., all the down in a 70 x 60 quilt is condensed into a 60x35 quilt (roughly speaking).

thank you for this detailed answer. it is really useful for my purposes...

btw, these Costco quilts are claimed to be 700 fill power. in your experience, how low in temp does this quilt work?..

[MattK]

how low in temp does this quilt work?

I have seen this asked a couple times but haven't heard any solid answers, so I figured I would jump in.

I have had chance to test out this design a handful of times recently. It all boils down to: I have been toasty in the mid-uppper 40s, warm enough to sleep at 42* (though not particularly comfy), and been cold at 38*. I tend to sleep on the warmer side (ie, I don't need as much to stay warm).

So I would rate this UQ at 45*.

For what it's worth, I was either in a very protected site or under a full coverage hex tarp, wind was minimal, no rain, I wear a 150 weight wool hoody silk long underwear and light weight wool socks to sleep, and I used my GG SitLite pad under my feet.

I also was using my Costco top quilt with sewn in 3d footbox on two occasions, and my 3.6oz/sqyd CS Apex topquilt with zip footbox the other four times.

[Secondmouse]

I have seen this asked a couple times but haven't heard any solid answers, so I figured I would jump in.

I have had chance to test out this design a handful of times recently. It all boils down to: I have been toasty in the mid-uppper 40s, warm enough to sleep at 42* (though not particularly comfy), and been cold at 38*. I tend to sleep on the warmer side (ie, I don't need as much to stay warm).

So I would rate this UQ at 45*.

For what it's worth, I was either in a very protected site or under a full coverage hex tarp, wind was minimal, no rain, I wear a 150 weight wool hoody silk long underwear and light weight wool socks to sleep, and I used my GG SitLite pad under my feet.

I also was using my Costco top quilt with sewn in 3d footbox on two occasions, and my 3.6oz/sqyd CS Apex topquilt with zip footbox the other four times.

great! to be sure though, you are talking about a reduced size quilt, where the seams are ripped and the down is shifted into a smaller area before some portion of the shell is removed?

urbanawiz says his end result is baffles with close to double the amount of down, giving 1.5" of loft. is this what you're talking about?..