I am working on a few MYOG items for a "sub 3-lb gear list" Hike I am planning early in October. If anything but a warm weather hike in this weight range is contemplated then some kind of system to stay warm is necessary.

I have been playing with the math for a very light quilt that will be NO larger than necessary for my size. Unlike some folks that are not as tall and wear smaller sized cloths and shoes, I am 6' tall with long arms (think XL upper body garments) and wear a size 11 trail runner. Anyone that wears larger than a size medium and size 9 shoe should get some kind of "handicap" like golfers get. I know that this has been talked about by some of our SUL Hikers and someone we all know was once so generous that he let a taller person hiking with him take (ONE OUNCE) off his weight total.

How it all starts:


Before starting this Quilt I looked at as many different ideas for quilts as I could and read about what others were using. I spend a lot of time planning my projects and do a lot on paper before I cut material. For this quilt I spent a couple days working out all sorts of different ideas for the size I needed and the material weighs. My weight goal is 7 ounces or less. I am using 1.9 oz per sq yard Polarguard Delta as my insulation. For the fabric I am using Cuben and light Silk. This is the only combination I have materials for that will give me the low weight I am after. I don't know how the Cuben will work used like this but I will find out on my hike in October. The Cuben will be on the outside and I think it will work OK.

This afternoon I started the Prototype. For this Quilt I am making my Prototype out of some $1 a yard denim from Wal-Mart. You can see a lot of lines on my material as I made different changes right up to the time I cut the material. I expect this quilt to be on the easy side vs some things I have made. The time I spend on the Prototype will make the finished Quilt go fast.

Prototype:

Do you plan to turn the quilt inside out (cuben normally outside) to dry it out? If you end up wet or wearing wet clothes obviously the water will go into the PGD and be unable to go through the cuben.

I've been playing with an ultralight bag/bivy combo in my head. Cuben bottom, ultralight silk liner and baffles, WP/B top (or cuben?). Down would be best but possibly with my hooded Micropuff vest (modified) I could get PGD to stuff small enough and be light enough to be okay at freezing? It would be my perfect racing bag where I could just pull it out and sleep, cocooned inside in bad weather. I know some are too cloastraphobic to do this but I don't want to setup a tarp and like to just bury myself in my bivy if things are crappy. I only need to sleep 3 hours or so in races and then get up and keep moving.

Insulation on the top for most like a top bag. Insulation all around for the feet and lower legs (no ground pad or pack there). No insulation in the hood but drawstring closable opening like my montbell bivy to leave open in nice weather and to almost totally close shut in a storm. Hooded vest and possum wool hat for head warmth plus wearing while making breakfast or when stopped in colder weather.

I know we're probably after slightly different things Bill but I love your ideas and willingness to try things out. I'll be watching the thread.

Bill-Theoretically Cuben will degrade your insulation if it is on the top layer and it will become a potentially uncomfortable vapor barrier if placed on the bottom layer.

Cuben on top - Your body will loose about a liter of water each day through insensible perspiration. The water will pass through the silk and into the insulation but not be able to pass through the Cuben. It will condense on this colder top surface and then wick down into the insulation. The moist insulation will then conduct heat away from your body up to 25 times faster than dry insulation.

Cuben on bottom – The Cuben will act as a vapor barrier and your insulation won't degrade but classical warm weather vapor barrier comfort issues with body moisture will plague you. Also you would need to quilt the insulation to the top silk layer to prevent moisture migration through the bottom’s Cuben seams.

How much of a weight penalty would you experience if you used silk on both layers of the insulation? There are no issues with that configuration other than the fact that your quilt will have approximately .3" loft. In combination with Cocoon top/bottoms with .3" loft, that will only keep you warm to about 70F.

Edited by richard295 on 08/27/2006 20:14:35 MDT.

70 degrees? I just did a night holed up in a bivy with only a micropuff pullover, possom wool hat and hooded windshirt. No leg insulation to speak of other than my tights. 26" torso pad, pack under my head and my food bag under my thighs. While I wasn't the most comfortable I've ever been, I was able to sleep the majority of the night and it got into the 40s for sure plus it rained for a bit.

Christopher-Extrapolate Bill's loft number from Mike Martins table at http://www.backpackinglight.com/cgi-bin/backpackinglight/bpl_sleeping_bag_position_statement.html to find out what top loft an average person needs for a given temp.

I previously posted an explanation on this forum for Bill explaining how to adjust Mike's loft tables for each individual. In summary, Bill needs even more than the extrapolated table values.

Was your bivy planned or a contingency? Most people like Bill would end up shivering during the night using your equipment compliment. This can maximally increase surface heat production by 500%. However, this is a time limited safety net because of depletion of muscle glucose which leads to... oh no we don't want to loose Bill. He is a major contributor to innovation on this forum.

Edited by richard295 on 08/27/2006 22:17:44 MDT.

My bivy was planned but somewhat as a test to see my limits. I was with someone who knew what I was up to and could get me warm had it gotten really cold or I did not do well. Due to our camping location and the rain the overnight low was colder than planned.

Prior to bed I rode around 20 offroad miles and ate a hot dinner. I was mostly dry but my base layer was damp from the evening's rain and splash from the puddles. My tights and pullover were dry. I was only comfortable sleeping for 1 hour at a time during the coldest part of the night although initially I slept for 3-4 hours. The next day I got up and rode another 60 miles or so in on and off rain with no ill effects. Nutritional intake and muscle recovery seemed normal.

Thanks for the link to the chart. Drafts played a big part in my temperature regulation and it was quite noticable how much by bivy was open and which direction it faced (into/away from the wind). I'm still learning a lot about this stuff and the fact that each person is different throws another element into the mix.

EDIT: FWIW I'm 24 years old, male, 5'11", 155lbs. Thought it might be useful information for someone searching later at least.

Edited by Pivvay on 08/27/2006 22:29:09 MDT.

I have been slowly typing away and didn't see the above posts till just now. The following is in reply to the first couple comments from Christopher and Richard.

To both Christopher and Richard, Thanks for you input and ideas.

The issue of the using the Cuben material has plagued me ever since I thought it was the only way I could stay under the 7 ounce goal I have set. I have been scheming for a way around the Cuben material ever since I posted the remark about using it. If I expected to be cold enough for a vapor barrier to work the place for the Cuben would be on the bottom. One layer of PG - Delta or Climashield XP would not keep me warm alone if it gets very cold. What I want is something for a temperature range down to maybe 45 to 50 degrees. My pick of clothing would support my sleeping system and I could go to "Down". I have a few reasons why I want to try one of the two synthetic insulations listed.

The end result of working through this all afternoon and up till a hour or so ago is that I have "Down-Sized" the Quilt a little more. I have some Pertex Quantam and have gotten the Quilt "square yardage required" down enough to go with the Pertex Quantam for the top and Silk for the bottom. Adding one layer of the 1.9 oz PG - Delta brings the total material weight (on paper) for the Quilt to 6.46 ounces. This gives me a little extra for the other things necessary and should still stay under my 7 oz goal.

I have a bit of Climashield XP and it is easy to buy in small amounts. Being a new generation insulation, when dry it is a much better insulation than PolarGuard Delta. As more Climashield XP is used it may prove better than PG-Delta when wet. However, for now if I think I might get wet I want my insulation to be PG-Delta. One of the things I want to do is make a quilt like this one but with Climashield XP. Then I can do some testing for myself.

The question of how much or how thick the insulation needs to be for a given temperature when using one of these synthetics seems to be divided into several ideas. Down goes by loft and a synthetic goes by ??? This is where it gets interesting and I am not smart enough to really understand. That is why I want to do some of my own testing.

I am sure that my Cocoon top and bottoms are good much lower than 70F. I will be up in Georgia in October and if it is cold enough I will be able to see how warm I am with the Quilt and a few other things I am taking to test. I will not be far from a warm bed where I will be testing my stuff. Then if it seems to be good enough I will go on a hike for a couple of days. Still close enough to bail if I get to cold. I use the old indian way to see what the rating of my insulated stuff is, am I warm in it, yes or no. How much other stuff do I need to put on to get warm. Do I need to go to a warm house now.

Anyway.

Richard, I really appreciate your input.

Christopher, I am not claustrophobic and have curled up under very little at times to try and sleep, stay dry or get warm. Cocooned is a good word for it.

I will try the Cuben on something like a quilt one day if only to prove to myself it doesn't work. I might get surprised. Cuben has made a couple of test runs of a Breathable product that I was told weighed in at 0.7 ounces a sq something. I am not sure if that was based on sq yard or sq meter. I would love to see it happen.

As a lone MYOG person I have few chances to get the really good stuff. It has happened a few times and I appreciate those folks that helped make it happen.

How to figure the amount of synthetic insulation needed for a given temperature range.

Note: Like working with Down these are "ball-park" numbers and field testing should be done to test the amount YOU need for any given temperature.

I have both Polarguard Delta (PG-D) and Climashield XP (C-XP) synthetic insulation. The information I have for the Clo value of the the PG-D and the C-XP came from Brian Emanuel, Director of Sales for "Western Nonwovens" the company that makes both of these two products. The Clo for PG-D is .67 to .68. The Clo for C-XP is .77. To get an idea of the temperature range for something made from one of these (this is a ball-park number) you weigh a sample piece of the insulation. I cut a 6" square of each and weighed them on my gram scale. the PG-D I have came out 1.9 ounces per sq yard. The C-XP came out 2.41. The PG-D was about between 1/2" to 5/8" thick. The C-XP was 3/4" plus a bit.

Working first with the PG-D I take the weight per sq yard of 1.9 ounces and multiply that times the Clo of .68 and get 1.292 . This number equates more or less to the typical loft rating like we use with Down. With 1.292" (for want of a better word) loft and looking at the table in "2006 Revision by Mike Martin -Backpacking Light Position Statement on Sleeping Bag Temperature Ratings" it would seem that this would give me a bottom temperature range of 50 degrees "F". We all know that this type of rating is just a base line and maybe high or low for any given person. It does provide us with a number to work with.

When I did the math for the C-XP at 2.41 ounces per sq yard times .77 I get 1.848" loft??. The extra weight of the C-XP (0.51 oz per sq yard) gives me 0.556" more loft per sq yard of insulation. With one layer of this C-XP my base line temperature low should be 30 degrees "F".

What can I do with this information? Well, if my new quilt was made with PD-D I might be able to use it down to 50 degrees "F" ???. If I wanted to use C-XP I would only add 0.97 ounces and might have a low temperature range of 30 degrees "F" ???. Add less than 1 ounce total weight and gain 20 more degrees "F" ??.

That would give me a 7 ounce quilt good for maybe 50 degrees or an under 8 ounce quilt good for maybe 30 degrees.

Interesting, but how do I test this to see if my numbers are in the "ball-park". I expect I need to make two quilts off the same pattern, one with PG-D and one with C-XP.

For now I just work to finish my prototype.

Bill,

I may very well be misinterpreting your hypothesis. From your math I am inferring that clo multiplied by weight per S.Y. gives a number equivalent to thickness of down. I call this your hypothesis because you included ??? after your calculation.

As I am about to embark on a synthetic quilt project, I have been contemplating all this clo business and following these forums, especially between you Bill and Richard Nisley. This has certainly been a mysterious subject, loaded with smoke and mirrors.

I took your math one step further to test the “reasonableness” of this clo times weight approach. Taking your measured 2.41 oz/SY times the .77 clo does give the answer of 1.848. Now, if this is an equivalent thickness of down, we can calculate how much the down would weigh to provide that same degree of insulation.

Let’s take a square yard of down that is 1.848 inches thick. That volume is 36”x36”x1.848”=2395 cubic inches. Now, let’s figure out how much down it will take to fill this volume; and we will use the “good stuff,” 800 fill power! (1 oz. of down will fill 800 cubic inches of space). Divide 2395 cubic inches by 800 cubic inches/oz. We get 2.994 oz.!

I believe that would mean that 2.994 oz/SY of 800 down, would be equivalent to 2.41 oz/SY of Climashield XP. In other words, Climashield is lighter than down providing the same degree of insulation! If we do the same calculation with Polarguard Delta, although the numbers are different, we get the same result the Polarguard Delta is more effective than down.

After studying the above figures, my gut feeling is that clo times weight isn’t directly comparable to an equivalent thickness of down. Of course I haven’t tested this out on that Brass Monkey … or is it a Copper Mannequin, they have over there in Europe to test such things.

Caution: this is nowhere near an expert opinion, just musings by someone who has been staying up too late at night, trying to figure out what to make my quilt out of.

Cheers

Michael,
My information came from two different people connected with the company that makes both products or who sell the product.

I can not backup in court anything I wrote in my thread. That is why I added the ???. When asked point blank about the use of the Down chart I was told to realize that a whole lot goes into a rating like for a sleeping bag or what ever before it goes on the market. In other words it is hard to be real certain because of other factors. Type of shell material, type of lining, type of construction etc. I was told that the Down loft chart for Down stuff is only a "maybe" at best for the same reasons. It does however give a person a starting point. These folks product a material (PG-D, P-XP and others) that (BMW, TNF etc) combine with more material and design considerations to market a product.

But that if I error on the conservative side, the way I wrote in my post the number should be good enough for planning/testing. Testing is the key. You may also note that I added "ball-park numbers" several times.

I asked them to look at the other thread where the Clo was talked about. I was told that the other idea for the math was wrong. That is all I want to say about that.

I asked the same question about Down vs this insulation but could not get a real answer. I did get that PG Delta is really great if you expect it to get wet. Not enough testing has been done with the C-XP yet or no one is talking about it to say if it is better, yet. I was really surprised that I was given as much information as I was. They said over and over that the new stuff they are making today is good, really good. That XP is the best synthetic insulation on the market but it is new and it will take a year or so to prove itself.

It may be that this new generation of synthetic insulation will come close to closing the gap with Down. I don't know. For me it is mostly about weight and if I expect to get wet. I really love Down, most everything I own to keep me really warm is down.

As for a direct equivalent to Down, I don't know. I asked for some "ball-park" numbers.
My one layer quilt might be OK to 55 degrees.
40 degrees about a Clo of 2 to 2.5.
20 degrees about a Clo of 3 to 4.
0 degrees about a Clo of 6.

For most of the answers to these and other like question WE may have to be the ones to prove or disprove what it takes to stay warm with this stuff. The big guys may never want to talk about it.

Bill,

I agree, we will have to be the final judge. While I am a down lover too, I am certainly not ready to work with down. My planned quilt project is a double quilt for warmer nights for my wife and me. I am planning the first with a single layer of Climashield XP and using what I learn from that, probably do a two layer quilt. For really cold nights up in New England, I go for the Western Mountaineering down. I think the quilt idea for two, really takes advantage of the weight per person.

The reason that I chose Climashield XP for my quilt is the method that you laid out in this thread! I didn’t try to compare it to down, but between various synthetics that were available to me, the XP seemed to have the best “math.”

As to it’s wet performance, time will tell. I worry less about that, as I do as many canoeing and kayaking trips as I do backpacking trips and have had to learn how to keep things dry. The two things at the top of the “gotta keep it dry” list are my sleeping bag and my coffee.

Keep us posted on these new synthetics!

Got to go put up hurricane shutters now, Ernesto is coming to South Florida! (Maybe I’ll pitch my tent in the backyard to test my staking skills!)

Mike

Bill,

Based on your loft numbers, PG-D seems to have a "loft per weight" of .33 while C-XP has a "loft per weight" of .31. Perhaps the most interesting part is that PG-D is not very available to the public so if we want to make our own gear we're mostly limited to C-XP. Plus I don't think we are able to tailor our synthetic loft amounts other than in integer intervals (1 layer, 2 layer, etc). With down we as MYOG people are more easily able to tailor the loft to our desired level. If I didn't care about wet performance I'd be after only down gear. Perhaps the combo (down bag, synth clothes) truely is one of the best options for most people. I will certainly see how far I can push a light down bag with a hooded synthetic vest.

Christopher,

If you look on the Climashield XP part of the web site at www.westernnonwovens.com the Data sheet list 5 thickness for XP. The data sheet lists the following:

2.2 oz per sq yard.
3.0 oz per sq yard.
4.0 oz per sq yard.
5.0 oz per sq yard.
6.0 oz per sq yard.

My guess is that what they list as 2.2 oz is what I have but weighed 2.41 oz per sq yard. I think Thru-Hiker has more than one thickness of XP.

Don't give up, the availability of PG-D might get better for us little guys.

Bill,

I've been reading with interest your threads on the kilt and now this one about your Quilt.

I checked the trip anouncement site, but there is now post about your 'crazy light' trip, which i assume is the same as your trip in october. I wonder what you're planning to take as shelter on this trip. We already know you'll hike in and sleep on your kilt, you'll sleep under the quilt, but what about shelter, backpack and cooking options are you thinking of to go sub 3 or sub 2 lbs?

Thanx, Eins

Bill,

Never say die! I won't give up on the PG-D, just put those projects on the backburner. I want to add more ideas but I have finally found a very talented cooperating sewer so I will just wait until I have some pieces in hand. The best part about all this is that it's lots of fun designing and building, and then most importantly testing outdoors! :)

Bill, while your efforts are indeed valiant, I think your methodology for coming up with real weight is flawed. You say you weight a 'small sample' (6" square). Manufacturing variance being what it is, I would think you would really need to weigh a larger (much larger?) piece. Any numbers derived from such a small sample are likely to be misleading.

As they say, there are three kinds of lies: lies, *BEEP* lies and statistics.

Hi Charles, Thanks for your comments.

I agree that the weight of my sample piece may not be true for the full amount of the Climashield XP or Polarguard Delta that I have. It does however give me an idea of the weight for planning purpose. As I start cutting the material that I use for my projects I weigh and record them to confirm I am close to my planning numbers or I am high or low. Then when I am finished with the (what-ever- project) I weigh it again for my finial finished weight. My scale is a Triple Beam Balance - Ohaus gram scale.

As for "your" term not mine of " REAL WEIGHT" all I said is that:

"I cut a 6" square of each and weighed them on my gram scale. the PG-D I have came out 1.9 ounces per sq yard. The C-XP came out 2.41. The PG-D was about between 1/2" to 5/8" thick. The C-XP was 3/4" plus a bit. "

Anyone but a lawyer should have taken that to mean I took a "sample" and weighed it.

The numbers are only important to ME at this point and give ME numbers for planning the amount of material necessary to reach my given weight goal. Am I misleading myself? I would expect anyone that wants to work with this stuff would sample what they have for "planning" numbers also.

You shouldn't be faulted in your methodology, Bill. You've long since proven you follow a regimented pattern of organization, planning and documentation.

Granted the sample sizes may vary slightly as to not give an accurate figure overall, however I believe that for the given moment the key piece of information based on weight as that the XP is lighter than the PG. That simple fact is enough to deduce the obvious statement, "Climashield is lighter than Polarguard".

As you are still in the beginning phases of the project and you hope to create full prototypes from both materials if you continue to weigh and document as you continue more data will be compiled and will then have the future possibility of comparison to others similar projects and results.

I agree. If there is a lighter alternative out there, Bill will find it. I’m surprised he hasn’t told us that he’s going to fill his “cheer-stick” pad with helium and that it weighs minus (-)2 oz. Of course, he will have to pack lead weights to hold it down. Now that’s a project for Bill; come up with a way to make lead weights lighter!

In all seriousness, that cheer stick pad blew my mind. It’s got go be the ultimate solution for weight, cost and comfort, plus, it gives you something to fiddle with in camp!

Michael,
I am working on a way to put Down into a CheerStic so I can turn it into a DAM for cold weather.

I am also thinking about marketing them for Bear protection. Bang them together and if that doesn't scare the Bears away it will make them laugh so hard at you that it should give you time to run away.

Maybe I need to see if Bears have a funny bone. The noise might make them think it is a gun.