Down Fill - 2 major questions

**tenzweiler** · 01-23-2023, 19:13

Alright, so I decided to do the crazy thing and make my own 20 degree down top and underquilt. My friends found out and now I'm apparently making 3 sets of them (plus one synthetic). I'm a masochist, it would seem. I have done quite a lot of research and think 800-850 fp is going to be my best bet, but I'm left with two major questions:

1. Is DWR/HyperDry/treated down necessary?

2. Where the heck can I get roughly 100 oz of 800-850 fp down without breaking the bank? I've messaged a few places that people mentioned here and on the ultralight backpacking site (some of the info is out of date), but haven't heard back from anyone. RipStop By the Roll was the best price I could find, but who do y'all prefer? Does anyone give discounts on big quantities?

Ok, those are my most important questions for now. I'm sure I'll have more. Thank you all in advance for your help! I should also apologize if I didn't dig deep enough in the threads... I'm still figuring out how to use this site.

Also, shoutout to the wonderful madman who created the CatSplat UQ Calculator. What an invaluable resource!

**Cruiser51** · 01-23-2023, 19:42

One caution with using that calculator .... determine the baffle width, for your desired temperature, using a 0% overstuff. The temp rating are based on the amount of down, which IMO isn't correct .... so set the overstuff to 0 or blank, adjust the baffle width to the temp rating you want. Then use that baffle width for the build.

You can then go ahead and add the overstuff to determine the quantity in each chamber, when you do, the temp rating changes, because the down quantity changes. This is where I disagree with the calculator, if the chamber size doesn't change, then the temp rating should remain the same. Overstuff is commonly used and there is value in the practice ... but I believe this is more a short coming of the down "actual" rating in the wild and inaccuracies in the chamberShape/performance once the quilt is installed to a hammock.

And I second the the Catsplat calculator and the contributions made later (Tachblades/Boston/Gadget) that made it so much better .... is an awesome tool for quilt making.

Brian

**Heavyhiker** · 01-23-2023, 21:00

Have you tried Dutchware Gear? They are actually a few dollars cheaper than Ripstop and for synthetic down, I have used their ‘UP’ insulation and what I like about it is that it handles just like down, in fact it doesn’t fly all over the place like down does. The only thing is I sleep cold so I have to add more than normal to my quilts

WV · 01-24-2023, 09:44

I use 850 hyperdry from Loose Goose. Buy it by the pound. I've been very happy with it. Presently adding the top half of a "bridge pod".

**gargoyle** · 01-24-2023, 12:46

For a google search use “bulk down”.
Is treated down necessary, nope.
With todays DWR treated fabrics the fears of wet down are kind of overblown.
With care of use or packing in a water resistant/proof stuff sack, you can prevent most wet issues. YMMV.
Calendered fabric is a must when using down.
Netting for baffle material is best. The tiny holes hold the down and help with loft and movement.

**tenzweiler** · 01-25-2023, 19:52

Oh my goodness, you just changed my world! I'm been searching so many different things and those google keywords helped so much! Thank you for the great advice.

**tenzweiler** · 01-25-2023, 19:53

I was looking at their stuff. Thank you for the info! I was wondering how they were.

**tenzweiler** · 01-25-2023, 19:54

Good advice! Thank you! I've been dreading working with down. I'll have to look into this solution.

**tenzweiler** · 01-26-2023, 18:19

Originally Posted by Cruiser51

One caution with using that calculator .... determine the baffle width, for your desired temperature, using a 0% overstuff. The temp rating are based on the amount of down, which IMO isn't correct .... so set the overstuff to 0 or blank, adjust the baffle width to the temp rating you want. Then use that baffle width for the build.
You can then go ahead and add the overstuff to determine the quantity in each chamber, when you do, the temp rating changes, because the down quantity changes. This is where I disagree with the calculator, if the chamber size doesn't change, then the temp rating should remain the same. Overstuff is commonly used and there is value in the practice ... but I believe this is more a short coming of the down "actual" rating in the wild and inaccuracies in the chamberShape/performance once the quilt is installed to a hammock.
Brian

Thank you for the info! Lots to unpack. I did the calculations with 0% overstuff with 2.5" baffle height on CatSplat, but now that I look at the other calculator (DIY Quilt Calc - the one with the HammockGear comparisons) the fill amounts are VERY different. Now I'm confused.

Also, I was thinking of using slightly lower fp for overstuff to cut costs, but that's just a theory for me right now. As for baffle shape I was thinking of U-shaped to decrease migration away from the feet (since mine are perpetual icecicles). Of course I'll throw in some noseeum mesh to help keep it in place. Does baffle width/number of baffles matter as much as height? This is so maddening but I'm obsessed and commited now. I wouldn't care as much if I was making it for just me, but I gotta keep my friends wanting one warm!

Sorry for all the questions and stream of thoughts, but I greatly appreciate the help.