DIY UQ, enough down?

[Merganser]

I'm working on my first DIY down UQ. It 78" long with 11, 2" differential (5"/4.25") baffles and 10 .375" pleats that add 7.5" to the length of the outer shell. I used a modified version of the UQ calculator to work out the dimensions and volume. I treated each pleat like a wedge to approximate its volume. It winds up adding about 5% to the total. At +25% I wound up at 1.33 oz/baffle.

I got it all marked, cut, marked and sewn and sewn and sewn without much trouble. My 850fp down came from Wilderness Logics on Monday so last evening I filled it. I put a whole bag in each chamber and then added 1/3 of a bag to each and rolled it shut and pinned it. Mostly, it looks great but I kind of expected to want to fill out a bit more at +25% than it does and I'm concerned perhaps actually need more down.

How do you determine when you have enough down? Does 1.33 oz sound about right for something of this size?

Any input is appreciated.

IMG_1999.jpg

[Cruiser51]

I carefully worked through the original calculators and the differential calculator and although they get you close, there are two things i think get overlooked ( a lot) or ignored

1) These are cloth structures and the calculators assume fixed structures. The cloth structures are going to migrate towards a circular shape if they can and this means the cross sectional area we calculated, is not likely to be upheld in reality ... as you move from a rectangle to a circle, the area for a given perimeter will increase, meaning the calculated volume is almost always going to be low

2) Our paradigm for a quilt is that you see the down straining the fabric creating that puffy look, we calculated the down to just fill the area .... and we calculated to get a certain amount of loft ... getting the nice puffy look has little to do with how much loft you have. If you have the loft you planned for, you have enough down IMO.

Brian

[Carrico]

Looks good to me, how thick is it when you let it loft up and lay it flat on the ground? As far as getting a nice filled baffle look, I've had much better luck just figuring out the volume as a square measurement. length of quilt * width of quilt * thickness that I want / fill power. But at over 14 oz of down I would imagine that it should keep you warm down into the twenties at least.

[Merganser]

Looks good to me, how thick is it when you let it loft up and lay it flat on the ground? As far as getting a nice filled baffle look, I've had much better luck just figuring out the volume as a square measurement. length of quilt * width of quilt * thickness that I want / fill power. But at over 14 oz of down I would imagine that it should keep you warm down into the twenties at least.

About 2.5 inches. The weight of a yard stick is enough to dent the chambers a bit. The calculator rating is about 10deg but 20 was the target. 2in baffle.

Mostly I am concerned that if there is not quite enough down to fill the chamber then I’ll wind up with cold spots, a problem I’ve had with my synthetic ups.

[Cruiser51]

I suspect a good shake before use will keep that distributed .... if your target was 20F and you figure you are at 10F, adding more down will take you even lower ..... away from your camping needs.

Brian

[Merganser]

Yeah, i keep shaking it. Maybe its looking better. Could be its just not spread out enough. I do trust the marh and have no desire to waste money on down I don’t need.

[Carrico]

Well according to the loft calculator 2.5 in should get you down to 20 degrees, but there's only one way to find out for sure;<)

[Merganser]

Well according to the loft calculator 2.5 in should get you down to 20 degrees, but there's only one way to find out for sure;<)

Right I'm a cold sleeper so I'm sure it wont get me to 20* but maybe someone. Based on when I camp I need it to be capable of taking me into the 30s at the lowest, which is what drove my specs.