Make Your Own Gear – Down Quilt or Sleeping Bag

[Addie Bedford]

Companion forum thread to:

Make Your Own Gear – Down Quilt or Sleeping Bag

[Roger Caffin]

Hi Dan

Well, … you have to understand there are two ways of measuring the performance of a quilt or a sleeping bag.

One way uses the European Standard EN13537 which has tightly controlled criteria. You can trust a rating done under this standard.

The other way is the 'old American way'. I won't explain how this is done (who knows?), except to say that controlled testing (using European Test labs to EN13537) has shown that American bag ratings have been MEASURED to be up to 15 C exaggerated.

There is NO WAY in my opinion and experience that 270 g of any down would work down to -7 C for a single person – unless you were wearing a down suit as well. Even claiming -1 C for 296 g of 850 fp down (a dubious fill power rating in itself) is suspect.

I could go off into my usual tirade about marketing spin and hype, but let's just take that for granted, shall we?

Cheers

[Dan @ Durston Gear]

Thanks….I kinda figured the 20F rating for the Ultra 20 was suspect. Your post was very helpful.

[Roger Caffin]

I should report that last week I decided to boost both red bags. My reason for doing so is that we do not actually do a lot of walking in the peak summer season any more – the heat and bushfire hazards have become too great. We do a lot more walking in the shoulder seasons and winter here now.

The bags (with 300 g of 800+ fp down) worked at -7 C when we layered them, snuggled up and had most of our spare clothing on as well, but … we seem to be doing a lot of that sort of cold-weather thing! And my wife sleeps a bit colder than me and was complaining that the down shifted to the sides too easily. I think that might have been due to a degree of underfill: the down was a bit too loose.

So, I undid the seams at the zip line and stuffed 120+ g more down into my wife's bag and 60 g into mine. The down was really top quality stuff – it was a 'representative sample' from an overseas down supplier which was passed on to me (at no charge!). I used the plastic bag and toilet roll core method, and got very little down spread around the house. It worked very well.

At the same time I removed the zipper from my quilt completely. Just dead useless weight these days.

The only consequence has been that I had to 'stretch' my wife's waterproof sleeping bag stuff-sack by 4" to avoid putting too much compression on the down.

Cheers

[Lynn Tramper]

"Even claiming -1 C for 296 g of 850 fp down (a dubious fill power rating in itself) is suspect."

Fill weight/warmth is also dependent on the design of the quilt/bag. I have been using the Western Mountaineering POD 15 and POD 30 for several years now. They have the down only on the top of the bag. The POD 30 is a true 30F bag (-1C) with 230g fill, and the POD 15 is a true 15F (-7) bag with 450g fill. IMHO these bags are pushing the limits of how much warmth you can get out of your fill weight. -7C for the Golite quilt is really pretty shoddy marketing.

[Brad Groves]

I know there are several people here who use, love, and find the Ultra 20 completely adequate. However, I generally only sell it as a summer quilt. Reason? It hangs next to my 40*F bags and seems to have no more loft than them. When I feel the loft between my hands it initially feels under-filled, BUT if I think about it a little more, there's actually fairly decent loft to the quilt. If you assume that, as a quilt, it is essentially one-sided loft, you can get by w/a little less down. 20*F? No. But I'd bet it's comfortable to about freezing. Feels like about 2.5-3 inches of loft (haven't measured).

[Jamie Shortt]

Lynn, I was thinking the same thing about design playing a significant role, not just the down fill weight. The ultra 20 saves on down under the user and saves on down that goes into the hood, because these portions of the bag are not part of the quilt. That being said the golite has 17% more down than the POD 30 that you listed and possibly a more effective design (no down in hood). So this might put the bag at say 25 degrees…not too far from golites 20 degrees rating.

I can say from personal experience that I have used the golite ultra down to a low of 20 degree extractly. I confirmed the temp from a weather collection station near where I camped (Mount Mitchell, NC).

I was inside a MLD bivy, under a tarp, with only a torso length 3/8" thin light. I only added a light fleece cap and montbell UL down inner jacket (6.8 oz so it not alot of jacket). I slept without the straps and I slept just fine.

My ultra 20 weighed 18.65 oz without the straps. Is this quilt as good as all the high end 20 degree sleeping bags? Probably not…but it is fairly close. I bet it is as good or better than any other sub 20 oz bag/quilt on the commercial market.

I just wanted to point this out before we bash golite too much. For one I applaud the effort of putting together a nice piece of ultralight gear that is available to the masses at a great price.

Jamie

[Roger Caffin]

Inside a bivy bag, with a down jacket and a fleece cap – OK. But that does NOT mean the Ultra 20 could handle 20 F by itself!

Cheers

[Lynn Tramper]

"Inside a bivy bag, with a down jacket and a fleece cap – OK. But that does NOT mean the Ultra 20 could handle 20 F by itself!"

Exactly. The POD 30 is a true 30 degree bag (just wear a base layer). No hats, jackets etc…are required at that temp. It also weighs 100g less than a GoLite ultra, and can be zipped up for serious wind conditions. That's not a reason to bash GoLite…but their claim of 5" loft is a very good reason to treat the company with skepticism. I'm guessing they mean 5" in the footbox where the quilt is doubled over. Very Very dodgy marketing.

[Jamie Shortt]

Roger, Yeah I really don't know how much I "cheated" which is why I listed everything I used to get to 20 degrees without being cold. Without the bivy and jacket I do think I would have been chilled. On the other side I do think my 3.45 oz of sleeping pad was probably lighter than one would assume to be using in sub freezing temps (might be wrong on that).

Jamie

[Lynn Tramper]

I know what you mean. I can easily push my POD 30 to lower temps by adding a Skaha hoody and MontBell UL down inner pants, but that isn't really telling us much about the realistic warmth of the bag or the varacity of the manufacturers rating.

I think the GoLite is a good piece of kit for folks who want a light down quilt to take them to freezing temps, and it's reasonbly priced…but take it much below freezing and most ordinary folks would need to add extra insulation. Partly this is the nature of all quilts (not just GoLite) where you have to add head insulation as a minimum, and the lack of zipper makes them more suited to bivy bag use when conditions get windy. I just think a temp rating of 20F for the Ultra would be, what do the Europeans call it????

Upper limit

Highest temperature at which a standard adult male is deemed to have a comfortable night’s sleep without excessive sweating

Comfort rating

Temperature at which a standard adult female can have a comfortable night’s sleep

Lower limit

The lowest temperature at which a standard adult male is deemed able to have a comfortable night’s sleep

Extreme

A survival rating only for a standard adult female. After 8 hours, hypothermia may start to start set in.

Methinks that without extra clothing, 20F for the ultra would be in the 'extreme' category.

[Cayenne Redmonk]

I got the impression from one of the podcasts around the internet that the 20F rating is the survival rating, not a comfort rating, and the quilts intended market is lightweight backpackers who use their clothing to boost their sleep systems comfort level.

[CW]

I typically run warm and was on the cold side of warm in the Ultra 20 with a Thermawrap jacket on in the high 20s to low 30s. That was in a double-wall tent on a Montbell UL 90 pad.

[Matt Lutz]

Roger:

How should one about figuring the proper height of a quilt? I am just under 5'6" and want something that will go only to my chin and no more. From the floor to my chin is 57". I plan to add 3-6 inches to this length, but not much more. Any suggestions?

I ask because most quilts I see are pushing 72-76." I'd like to keep the needed length under 72" so that I only need to buy 2 linear yards of fabric and not 3 (with plenty to spare).

I'm building my model in Google SketchUp. Semi-intuitive program that has worked well for me so far.

Also, I'm confused by sewing the long edges together. What happens to the baffle? Is any part of it sewn into the side seam?

Finally, any further advice on getting the proper baffle height selected? I am planning on using 9 oz of 800 down, for 7200 in^3. My surface area for the down is 2916 in^2. My thoughts are to use two inch baffles (50.8 mm), which gives the down a total volume of 5832 in^3 to loft in. Even if the down degrades 10%, this should leave plenty of room for the down to keep the baffles plump. Any comments or disagreement?

Thanks, as always.

[Roger Caffin]

Hi Matt

Length: floor to chin is NOT enough. For a start, when you are asleep your feet tend to point, adding at least 8". Second, there is nothing worse than struggling with the top of the quilt trying to pull it up another few inches around your neck on a cold night. Thirdly, when the quilt is stuffed the bulges from the down shorten the length anyhow. Be generous with the length: you won't regret it. Shaving inches off here can be very false economy if it leaves you cold. I would strongly recommend AT LEAST 76".

Now, buying fabric. I don't know where you are buying it from, but I am sure that they will sell in smaller increments than 1 yd. They may not sell *less than* 1 yd, but above that they are always more flexible. Surely! Make sure you aren't 2" short! False economy.

Sewing the long edges together: all I did was run the baffles to within about 1/4" from the edge, then I sewed the long edges together. The way the baffle gets compressed next to the seam will stop down migration. You can get more fancy and try to include the end of the baffle in the seam, but it really is not necessary imho.

Baffle height: for 9 oz of 800 loft down I would suggest a baffle height of only 1", not 2". Yes, this means the loft would seem to be restricted at the baffles, but that is not how it works in practice in my experience. It bulges more in the middle of the chambers. On the other hand, if you make the baffles too big the down is too free to move around, and it will tend to migrate around away from the centre of the quilt to the edges. Needless to say, that is undesirable on a cold night.

Note added: this is why 'overfilling' seems to work so well: the extra down helps to prevent down movement within the chambers.

Calculating down loft volume is a marketing gimmick. The way the shell bulges defies all calculations!

Cheers

[Seb Gronemeyer]

Hi, just wondering, won't using dress-maker pins result in a lot of tiny whole and therefore more down leakage?

[Roger Caffin]

Hi Seb

Well, that depends on where I put the pins. If they are in the hem at the side they don't matter of course. For the baffles, I try to put them right at the stitch line, so the small number of pin holes get 'over-written' by the needle holes as it were.

Also note that the pins I use are the very finest I can get. There are plenty of much thicker pins available, but I avoid them on the light fabrics.

Practical experience has been that this does not cause a problem, at least with the Microlight fabric and the #60 needles I use.

Cheers

[Mark Fowler]

Below is the technique I used for cutting the baffles when building my quilt. Used 1 metre of 150cm wide nanoseeum netting and needed baffles with a maximum length of 150cm so I set up to cut them from selvedge to selvedge. To do this I folded the netting carefully ensuring the netting was square and the selvedges aligned. Folding it twice lengthways I had a 38cm wide (4 layers) strip of netting 1 metre long.
On a cutting board using a rotary cutter I sliced strips across the 38cm of the folded netting every 60mm. These strips unfolded to give 150cm long strips. The roller cutter easily handled the 4 layers of netting with firm pressure. I used a heavy steel carpenters square which held the netting nicely in place and moved it carefully between cuts ensuring the netting did not slide around.

The baffles came out looking like they had been professionally slit – in commercial bag construction (Paddys in the 70's) we used 50 metre rolls of light tricot hot slit to our required widths.

The whole process of cutting the baffles took around 10 minutes.

I would also recommend hot cutting the shell fabrics or fusing the fabric edges with a candle flame. If you are using knitted baffle material (noseeum, nanoseeum etc) there is no need to heat seal it, but any light weight uncoated woven fabrics are best heat sealed.

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