There have been some great threads in here relating to creating a down quilt. I'm trying to decide if I should take the plunge. In particular, I'm trying to decide if I should use the kit at thru-hiker.com, which contains 12 ounces of 900FP down and the Momentum fabric for the shell and liner. The kit costs $160, which appears to result in an ~20 oz. quilt that is good down to 30* (is that accurate?).

On the other hand, if I can source 800+FP down at around $6.50 an ounce and buy the fabric elsewhere, it might cost significantly less (around $100).

I need help with the following questions:
- How much down will I need to make a quilt that's good down to a conservative 25-30*?
- Is it better to buy the materials myself or just buy the kit from thru-hiker?
- Are there better materials that I can buy other than Momentum90 or Momentum55?
- Though I can't convert my existing 20* down bag, I'm willing to destroy it to get the 750+FP down inside, and I think there's about 16 ounces of it. It could save me $100 on down, which is worth it to me, but how much weight would I be adding at only 750+ instead of 900 for equivalent loft? I could also use leftover down to make a hat.

Thanks!

- How much down will I need to make a quilt that's good down to a conservative 25-30*?

Warmth depends mostly on loft. How much down you'll need to reach that amount of loft depends on the dimensions of your quilt. Use Tim Marshall's quilt calculator to determine how much down you'll need.

- Is it better to buy the materials myself or just buy the kit from thru-hiker?

If you buy your materials from multiple places, you'll pay shipping multiple times, which may completely wipe out the savings you hope to achieve.

- Are there better materials that I can buy other than Momentum90 or Momentum55?

Some people think the Intrepid 20D fabric from OWFINC is the same stuff as M90... TiGoat thinks their SevenD fabric is the best ultralight downproof water resistant fabric. Others think that cuben fiber is occasionally a better choice, although breathable cuben fiber is interesting to say the least.

- Though I can't convert my existing 20* down bag, I'm willing to destroy it to get the 750+FP down inside, and I think there's about 16 ounces of it. It could save me $100 on down, which is worth it to me, but how much weight would I be adding at only 750+ instead of 900 for equivalent loft? I could also use leftover down to make a hat.

See the answer to your first question. I will say that I don't think it's worth spending $20-25 per yard on the best fabric if you're aren't going to fill it with the best down.

I agree if you're going to use lightweight fabric you should also use the best down

the math is, if you use 16 ounces of 750 down, you would need 16 * 750 / 900 = 13.33 ounces of 900 for the same loft, so you would save 2.66 ounces if you used 900 down

what do you need, 6 square yards of fabric total? that would be 4.5 ounces for 0.75 oz M50 or M55, 5.4 ounces for M90 or the OWFINC fabric, or 6.6 ounces for 1.1 ounce fabric

I'll make some assumptions about your quilt size to give a fill weight. You can always revise my assumptions with your actual dimensions in order to arrive at a more accurate number.

Assumed Dimensions:
Head: 50 in
Foot: 39 in
Length: 78 in
Taper: straight

You'll need 2" of single-layer loft according to BPL's position statement to reach 25°F. In addition, most reputable cottage gear manufacturers overfill due to test conditions for down not being very representative of the real world. Jack's R Better uses 15-22% over fill, I'll use 15% for my calculation.

Area = (50 in + 39 in)/2 * 78 in = 3,471 in²
Volume = 3,471 in² * 2 in = 6,942 in³
Down, theoretical = (6,942 in³)/(900 in³/oz) = 7.71 oz
Down, practical = 7.71 oz * 1.15 = 8.87 oz

Generally speaking, I would say:

40F - 7.5oz of 800-900fp down
30F - 9.5oz
20F - 12oz

If you check out the fill weights used by Katabatic, you'll find they're generally in line with this.

Thanks a bunch for the feedback everyone. I took everyone's information into consideration and weighed all my options. A few people PM'd me as well with their thoughts, so I had a lot of opinions!

In the end it looked like Thru-Hiker's kit for the quilt was perfect for my needs. Some say the SevenD fabric is better, but I would have paid a lot more for it compared to the kit. It looks like at the dimensions I'm trying to achieve, approx 2.5" of loft at a slight taper of 54" at the top for around 74" length, the 12 oz. of 900FP down should be perfect, assuming I don't lose too much!

Total came to $175. This was a big part of my decision, as I wanted a Katabatic quilt but just could not justify the $400 for a Palisade (in 6' wide). I'm also hoping to learn how to sew, and perhaps will make a tent if this goes well. I'll be sure to follow up with more information about the process once I get the materials.

Thanks to BPL for the encouragement to undertake something like this, which I never would have considered until a few weeks ago!

Hi Sean,

I am wondering if you made the quilt and how did it turn out?

Darren