Question For The UQ Masters

**Lost_Biker** · 08-26-2012, 09:52

Getting materials ready to make my first full length long tube down UQ. I have used the UQ Calculator (extremely helpful) and played with the numbers a bit. My question is: when does overstuff reach diminishing returns? Also if I make a 20* UQ with 20% overstuff, is it better than a 0* with little or no overstuff?

I do understand down quality and fill weight and will probably go with 800 fill, but thats not carved in stone yet.

I've seen recent posts about which is better - O degree or 20 degree UQ's, but my question is to overstuff or not to overstuff. I live in Indiana and the winter temps get to single digit to low 20's. I am a very cold sleeper.

My first impulse is to make a 20* with 20% overstuff, but don't understand the real world down mechanics enough.

Any guidance is greatly appreciated.

Please keep the math to a minimum. MAD777 made me think too hard last night.

**SteveJJ** · 08-26-2012, 10:13

Just a noob myself, but as I understand it, the amount of air trapped between the down is what gives you insulation and not the down itself, so to get better insulation for colder weather, you need loft space for the down to trap the air in, and thus your body warmth. That's why when you lay on a down bag, your butt can freeze. No trapped air, no insulation. So the UQ doesn't compress like a sleeping bag would, so it keeps your bottom insulated.

I just added a couple ozs overstuff to a 20 Zeppilen just ordered from UGQ to hopefully bring it closer to a 10 degree bag for Minnesota. That will help it be extra puffy without going thicker. I will be making a sock to surround the whole rig to block wind but hopefully wick out moisture and allow CO2/O2 exchange. I didn't go with a 0 degree UQ for fear it might be too efficient to be useful for most of the year. I'm hoping the 20 with overstuff is a good compromise, though I'm concerned it might be too much. I do have a JRB Nest that is OK to 40 (it's old and thin, likely one of their first ever models) and that too could be layered with the Zeppelin for additive properties.

I do have a double layer hammock so I can use reflectix, mylar, etc to add warmth if the down isn't enough, and if that's not enough then I can always wuss out and get a motel room or go home!

Hope this gives you some more to go on. No math needed. more down slows heat movement from your body, to a point, then inches of trapped (loft) air makes the difference. Overstuffing helps some, but loft helps more if I understand it.

FWIW,
Steve

**MAD777** · 08-26-2012, 10:50

Originally Posted by Lost_Biker

Also if I make a 20* UQ with 20% overstuff, is it better than a 0* with little or no overstuff?

Please keep the math to a minimum. MAD777 made me think too hard last night.

20% overstuff of a 20 degree quilt will give you a 10 degree quilt. (I did the math for you

)

**Lost_Biker** · 08-26-2012, 10:57

Thanks Stevejj and MAD777 for the guidance. I still have to think about which to build - 0 or 20* with overstuff, but I tend to agonize over little things.

And a special thanks to MAD777 for not making my head hurt today (but the day is still young).