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5oz XP rating of 20* with only 1.2” loft?
Posted: 03 December 2007 06:14 PM   [ Ignore ]   [ # 16 ]  
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Western Nonwovens makes over a dozen styles of continuous filament insulations. As your graph doesn’t identify the insulations being compared to XP it does not apply to the discussion at hand which is about XP and 3D.

The standardized clo values for 3D and XP are 0.63 and 0.82 respectively. It’s possible but not likely that my rep is mistaken; I keep pretty close tabs on this stuff and would have heard if the XP number was revised. 

In your case the belief that all continuous filament insulations are fundamentally the same and will flatten out in 30 days makes your decision to keep using a quilt that has lost its loft a reasonable one, as you think all insulations will perform the same in that flattened state.  If I thought my synthetic gear would flatten out in 30 days I might come to the same conclusions regarding using worn out insulation.

My own experience with these insulations is different and it leads me to different conclusions.  When you get around to trying something new enough to still be manufactured, let me know and we can continue this discussion.  Until then, your speculation on XP’s performance or lack thereof is just that.

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Posted: 03 December 2007 08:20 PM   [ Ignore ]   [ # 17 ]  
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It was a longshot to think that someone who believes that the pinnacle of continuous filament technology was a dozen years ago with polarguard 3D could be persuaded to actually try one of the newer products, but there’s always hope.

I dunno AYCE, even Jardine started using Climashield XP and he’s about as stubborn as it gets.  I would agree with that guy though, it is ludacris to think that a decade of research and development could produce a product that is warmer, more durable, AND more packable than polarguard 3d ;)

By the way, my XP quilt is still rocking out its 40*-45* comfort rating after being packed down to 3 liters after over a year! Great stuff

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Posted: 04 December 2007 12:20 AM   [ Ignore ]   [ # 18 ]  
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By the way, my XP quilt is still rocking out its 40*-45* comfort rating after being packed down to 3 liters after over a year! Great stuff

which weight XP did you use?  (I’m looking for a summer quilt and am dithering between 2.5oz XP and 3.7oz Combat)

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Posted: 04 December 2007 04:41 AM   [ Ignore ]   [ # 19 ]  
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I used the 2.5 oz XP. If I had to do it over again though, I would have been much more happy with the 3.7 combat.  I used the 2.5 on 80% of my trips and supplement with synth jackets, fleece pants, and/or rain gear to take it below 40 or 45.  I’ve even taken it down to 15* or so with lots of other stuff when my 6oz ploft quilt was being borrowed.  For reference though, I sleep like a furnace.  almost enough to take old slumberjack bags to their advertised rating, and thats a lot!

I think ron bell has a pretty good rating system on the MLD website, although it is conservative for the purposed of being honest to people who sleep a bit cool.

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Posted: 08 December 2007 01:57 PM   [ Ignore ]   [ # 20 ]  
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Wow, you guys have my head spinning with all this tech talk and percentages, but it is a very informative thread.  There is an interesting interview with someone at Western Mountaineering about their bags and down and temperature ratings which can be heard via Podcast at the WM website.  Question:  To achieve a 5” loft with a down quilt don’t the baffles need to be 5”?  The kit plan calls for 2.5” baffles.  Someone above mentioned that 2.5 on top and 2.5 underneath adds up to 5” of loft, but a quilt does not have an underneath.  Or does the material loft up or stretch out so that a 2.5” baffle is all that is needed? 
The quote “for God’s sake make the quilt wide enough” rings loud and clear.  The problem with flat quilts is that they will shift and ride up as you turn when sleeping.  Cold drafts will awaken you.  Trying to close off the foot end with velcro and a draw cord works for awhile, but do not be surprised if you wake up in the night with your feet sticking out the ends. All this happened to me recently while out in 15 degrees in my new Momentum/Silnylon bivy and Neato Man patterned quilt!  A quilt with a footbox works better (like the quilt design at this site), but best (for me) is a sleeping bag.  It just will not slip off in the night. You have surround down! If the down beneath is compressed, so be it. http://home.comcast.net/~neatoman/quilt.htm
As for the thru-hiker, I believe that the body will adjust to being outdoors for months at a time.  A “cold sleeper” will probably become a “warmer sleeper”. Maybe it will be just enough to make up for the loss in loft! (Hopeful speculation, not fact).  But,  a friend moved from NH to Arizona and had a hard time adjusting to working out in the heat.  He just could not seem to get enough to drink.  Eventually his body adjusted.  He felt fine drinking a lot less water.  Another variable would be the warmth of one’s body at night time before getting into one’s shelter.  One evening I jumped into a mountain lake for a refreshing swim.  The water was so cold, I shivered most of the night.  Other nights with similar air temperature, I went to bed warm and slept warm.  Nourishment, too, plays a role in how warm one sleeps.  Nevertheless, some standard needs to be determined to try to estimate the temperature rating of sleeping systems, so I learn from this thread.

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Posted: 08 December 2007 04:50 PM   [ Ignore ]   [ # 21 ]  
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That neatoman quilt design is a fine example of a quilt that isn’t wide enough for many side-sleepers, including myself. For a back sleeper, it is perhaps excessively wide. The simplest way to figure out how wide your quilt should be is to buy 3 yards of $1/yd fabric at walmart and sew it up and then see how it works. Then add the appropriate number of inches for seam allowances and the thickness of the insulation. The draft flaps on the side help a LOT in keeping the quilt in place when side sleeping (tuck the flap under your hip). Everyone has different ways of sleeping and the only way you will know how to dimension your quilt is to experiment. I am making a new quilt primarily because I am dissatisfied with the dimensions of my old quilt. (As the discussion above indicates, I am not particularly dissatisfied with my old insulation nor do I expect huge improvements with the new insulation.)

Just as everyone has a different way of sleeping (back, side, stomach, quiet versus thrashing about), everyone has a different need for warmth and indeed this can vary, as you note, as we become more adjusted to sleeping outdoors and it is also dependent on how much food you are eating and other factors. Each person has to establish their own need for insulation. There is no need for temperature ratings. Do manufacturers of blankets and sweaters sold at an ordinary department store put temperature ratings on these? Of course not. Some people need 1 blanket, some people need two. Some people need 1 thin sweater, some people need 2 thick sweaters. You have to figure this out on your own. In general, everyone intuitively knows that thickness more or less equals warmth, but that it isn’t the whole story. So when you go to an ordinary department store and you feel a very thick coat, you know it will be warmer than a very thin coat, in general. Of course, there are other factors as well. Once you have established your need for insulation, then it is a simple matter to decide whether a coat, or sweater, or blanket or sleeping bag or quilt will be warm enough. This is particularly true if you are always using the same type of insulation, such as continuous fiber polyester, in the case of this discussion. I know what 6 oz/sqyd of Polarguard 3D will do for me. I am also pretty confident that 5 oz/sqyd of Climashield will do a little less, but that it will come sufficiently close for my purposes. I already have to supplement the 6 oz/sqyd Polarguard 3D with an insulated top at a certain temperature, and I will just have to supplement the 5 oz/sqyd of Climashield at a slightly higher temperature. No big deal, especially because I am saving over 3 oz of weight plus a lot of space which I can use for additional clothing. But like I say, everyone has to determine for themselves what 5 oz/sqyd of Climashield will do for them, or for that matter, what a down bag with 5” of double-layer loft will do for them. Temperature ratings are meaningless.

Finally, loft for sleeping bags is normally quoted as the double layer warmth. So a 5” bag has 2.5” on top and bottom, and is thus equivalent to a 2.5” quilt. For clarity, I recommend people say single-layer loft or double layer loft. It is also less confusing to say “tolerant of cold” rather than “warm sleeper”, because many people think a warm sleeper is a person who needs lots of warmth to sleep comfortably. You are using the terms “warm sleeper” and “cold sleeper” correctly, but “tolerant of cold” and “not very tolerant of cold” are much less likely to confuse.

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Posted: 08 December 2007 05:46 PM   [ Ignore ]   [ # 22 ]  
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My Neato Man quilt is 5’ across the head edge and 4’ at the foot.  I forget how much down I put in, but it almost got me through a 15 degree night that started around 20. (I wore a hat, liner gloves, long underwear,socks, a windshirt and Golite Reed rain pants) It has worked pretty for me well summer and fall.  I understand that “meaningless ratings” applies to bags because person A might be warm in a 20 degree bag and person B might be cold when the temps are the same. However, bags do need to be designated with ratings, because it gives people a standard by which to judge.  Customers shopping will inquire from a salesperson about which bags are appropriate for X degrees and then be informed about the differences.  You could say that sizes are meaningless for shoes, too.  But, like bags, there needs to be a starting point for the question, “What size?”  For example, my foot measures 9.5, but I wear anywhere from an 9.5 to 11 depending on the manufacturer. The 9.5 gives me a place to start. Some shirts of mine are medium, some are large, and so it goes.
BTW I just happened to notice something els about my quilt as I look at lying out on the floor next to me.  In some of the sections, the down has shifted to the edges leaving the middle a bit thin.  A shake or two will shift the down back to lie more evenly, but that cannot be done while in the bag, ie. I’ll have a cold spot.  Synthetics should not have this issue.  FeatherFriends and Warmlite down bags (and maybe others) do not have down on the bottom of their bags, but have slots for sleepng pads.  Sewing in such a bottom is a way of solving the side-draft-slippage issue with quilts.

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Posted: 08 December 2007 11:46 PM   [ Ignore ]   [ # 23 ]  
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Comparing size to warmth is a really stupid analogy. The correct analogy is assigning WARMTH ratings for shoes. This is only done for pac boots because everyone recognizes that it is obviously meaningless. People have different needs for warmth. If you want an objective rating for warmth, then use clo. If someone doesn’t know anything about how much insulation they need, then they should just use the inches system as a rough estimate. Degree rating = 100 - (40 * inches of loft). Thus a 1 inch thick quilt or blanket or bag (single layer) is warm to 60 deg. A 2 inch thick quilt or blanket or single-layer bag is warm to 20 deg. This formula is from the army, from long ago, and is for healthy and muscular young men (soldiers), and is roughly true for all insulations. Modern micro-fiber insulations (Climashield, Thermolite, Microloft, etc) will be warmer per inch of loft than the formula suggests. Down will be significantly less warm than the formula suggests for side sleepers because of the tendency for down to fall off to the sides when side sleeping and leave a cold spot on top. So that’s the formula the salesman should use. If the customer is a woman, especially a smaller non-muscular older woman who is not hardened to sleeping outdoors, add 20 to 40 degrees worth of extra insulation.

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Posted: 09 December 2007 02:33 AM   [ Ignore ]   [ # 24 ]  
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I was not intending to compare shoe size to bag warmth.  I was trying to compare the dilemmas of finding the right bag for the right temperature and the right shoe size for a size 9.5 foot.  A 20 degree bag off the shelf might not keep me warm at 20 degrees and a 9.5 shoe is often too small for my 9.5 measured foot size.  Hmm…“What are you talking about, Willis?”  Forget it.  (In the early 70’s, Warmlite stopped including temperature rating, but the customers kept asking, so they now include a chart. Customer feed back helps manufacturers keep their estimates “honest”.  Remember, estimates are only opinions.  The science is not exact!)
In deference to frprovis , I did flunk the analogy section of the Grad Record exams.  I have little idea of the loft measurements of my various sleeping gear, but I do know which ones keep me warm at which temps, because I sleep out doors in them.  Low and behold, my homemade 10 degree down bag, kept me warm at zero degrees in a bivy.  Hmm…could my 10 degree bag really be a 5 degree bag? Then, again, I was wearing clothes, so maybe it is only a 15 degree bag.  Maybe I’ll ask a ask a bag lady, but that would probably be a bad analogy.
PS I started a new thread (especially since my remarks in this one did not add much) showing photos of my various quilts.  In the Ray Way quilt (2005) I used two layers of whatever synthetic fill he sold at the time and his suggested temp rating for it was 32 degrees F.

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Posted: 14 December 2009 02:14 PM   [ Ignore ]   [ # 25 ]  
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This description of the Thermarest Haven sleeping quilt gives a certified? en rating of 20 degrees.  Assuming this is a legit rating system it sure makes things easier for the user.

http://cascadedesigns.com/therm-a-rest/sleep-systems/fast-and-light-sleep-systems/haven-sleep-system/product

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Posted: 13 September 2010 12:43 AM   [ Ignore ]   [ # 26 ]  
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Wow! I’m impressed with the depth of knowledge you guys are sharing.

Where does closed cell foam fall in this discussion of insulating value per inch?

What would be the temperature rating, for example, of a sleeping bag made entirely of 1/2 inch thick closed cell foam?

I made one a few years ago and experimented with it.  It appealed to me because it took the place of both the sleeping bag and the tent.  There were a few obvious problems (e.g. condensation, it didn’t drape well, etc.) and I got tired of experimenting with it.

The thing that discouraged me most, however, was that I couldn’t logic out whether it was even worth trying.  In other words, if I could get confortable with this contraption how cold could I expect to keep warm with it?  Could I, for example, expect to keep warm enough in a 3 lb closed cell bag/shelter as I currently do with a 2 lb down bag in a 3 lb tent?  If so that would be a pretty good saving of weight.

Opinions, insights or comments?

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