I think Bill may have the answer on this one, but there may be some other people out there that know of something lighter.

As I've said before I believe very strongly in animal rights and do my best not to use animal products etc.. So you can see my dillemma when it comes to a sleeping bag / quilt. I have two options 1. I use hand picked Eider down from Nunatak (which isnt very likely) or 2. I go for Synthetic.

This doesn't worry me so much these days since the weights of synthetics are almost reaching similar levels of down.

So the question I am asking is what is the absolute lightest fabric that could be used to make a synthetic bag?

I've seen Bill mention some silk at around .5oz which seems to be the lightest so far. I'm just wondering is there anything lighter that is feasable to be used?

If my logic is right a synthetic bag doesnt require the use of downproof textiles since it is mainly there just to cover the insulation. This to me seems to open up the amount of fabrics that can be used. I have also noticed many times before that the material used for the outer bag for down is the heaviest part of the bag. Upto 60% of the total weight. My thought is that if lighter non-downproof fabrics can be used for a synthetic the overall weight cost of a synthetic bag may pay off.

I also considered the effect of wind since these materials may not be too wind resistent. But I am going to go the way of a BMW or MLD bivy in short time, which should eliminate this problem.

The bag I want to make will most likely be a 40F bag since my lowest temps in winter barely reach the 30s. On a side not here I'm just curious to know what the average nightly temperature will be for the PCT? My friend and I are planning a through hike in 07 and to date I've found no such information. It seems that because most of the material on it is from the area people must already know what temps to expect.

And finally does any one know where I can find a pattern and some instructions for a bag? Im going to make adjustments to it to fit the other criteria that I want but something to start with would be helpful.

hey jacob,
i could be wrong, but on mark verber's site he quotes a letter from r. jordan discussing the minor but key differences in primaloft and polarguard. very interesting.

i got a 2004 north face propel 40F at campmor a couple months ago. quantum and polarguard. for 129. it's an amazing bag and weighs just 16 oz. i just went back there (assuming you can barely BUY the materials for that price) and they seem to be gone. a quick search of the web may reveal a few closeout bags like this somewhere out there.

you could customize it pretty easily. it has no zips or hood. i plan on wearing with cocoon pants and and micropuff pullover down into the thirties...

i just got a MLD soul bivy. a really well made sack.

i saw some patterns at thru-hiker website. if i recall. good luck.

Thru-Hiker has 0.8 oz/sq yd DWR ripstop nylon, but it sounds like you want something lighter. Silk might just be the way to go.

Rockywood Fabrics homemade gear page:
http://www.backpacking.net/makegear.html
Scroll down on the left side to "Sleeping" and check out 6."Jeff's Bag" That would be a start, for some ideas.

For info on how much insulation to use check out the info on the Ray-Way Quilts kits, on synthetic insulation. Their quilts look scrumptiously warm and cozy. If I weren't using down quilts, I'd probably make one of theirs.

Jacob, Do you know where silk comes from and how it is processed. I only ask since you state that you want to "do my best not to use animal products etc."

Silk comes from silk worms. I helped raise some a few years ago. It was very interesting. We bought 100 silk worm eggs and were sent 680. I think they all lived. You can't believe how much they eat toward the end of their growing period.

In the wild they go from a silk worm and then spin a cocoon around themselves. After so much time they turn into a moth. They eat there way out of the cocoon and fly away. This cycle repeats itself over and over.

When they are grown for their silk they are allowed to spin their cocoon. After a certain number of days in the cocoon (I don't remember how many) the cocoons are put in an oven and the heat kills the silk worm. The cocoon is then processed into a fine spun thread. This thread is woven to fabric.

After knowing this, if you still want information on using some very light weight silk for your sleeping bag, let me know.

Edited by bfornshell on 08/26/2005 23:05:50 MDT.

Thanks guys, already a huge help.

that bag looks something like I want. I can work with it anyway.

I already knew how they made and processed silk. The issue of rights rested in that area a good many years back. I was trying to decide whether invertebrates or which invertebrates showed only fixed animal behaviours rather than those with cognitive though. I came to the conclusion that most invert phyla are without sentience. So the answer is I don't mind the silk manufacture. And I would be very greatful for information on what the limits of silk are and where I can get freakishly light stuff.

However if anyone still knows of any synthetics approaching this weight I would love to know.

Harry,

If you see this post, would you mind replying and telling me a bit about the MLD Soul Bivy? What I am particularly interested in knowing is how easy/difficult it is to get into and out of the bivy. Have you tried it in the rain yet? If so, how heavy was the rain and how long was the bivy exposed to it. Any other info about the bivy you feel is worth sharing would be appreciated as well. I've already read the specs. Many thanks, pj

Edited by pj on 08/27/2005 02:30:58 MDT.

hey paul,

bivy is beautiful. it's got a little zip down the side a ways, (it was a prototype so i'm not sure how it compares to his basic soul bivy.) it's pretty easy to get in, a bit of climbing and scooching. par for the course. my sleeping bag has no zip at all...LOL.

i'm going to sew an additional grosgrain loop onto the grace tarp i got as well. a bit further under the edge (to hang the bivy). better to protect my head from eventual rain.

haven't had any precipitation in weeks. i'm in southern cal. 105 in the shade today. maybe tomorrow i'll do a hose spray test and let you know the results. best,

Harry,

Many thanks for the swift reply. Appreicate the info. I also had Mr. Bell put a side zip (amongst other mods) in the Epic Soul Bivy he made for me a while back. Would really appreciate hearing 'bout the results of your "hose spray test". Thanks again. Take care, pj

I just noticed that thru-hiker had some pretty light Spinn. I think I'm going to buy a few yards of it and fashion a tarp and a pack from it. It seems like a cheap way to go.

I dont suppose anyone knows where to get the cuben fabric and the silk that Bill has been using. I've poured over the old forum pages but couldnt find it anywhere.

Also does anyone know where I might pik up some Delta or 3D? I read in that article that BPL may have lots of it due to bulk ordering. Maybe Ryan would be able to assist.

Edited by nihilist37 on 08/30/2005 22:51:19 MDT.

Thru-hiker also has 3-D

JT,
High quality down - 800+ cubic inch - does not need much in the way of 'down proof' fabric because 'down-proof' really means 'quill proof', and high loft down has few quills. The lightest stuff you can find will work - consistent with the desired level of durability and wind/weather resistance. I've had good luck with 0.8 oz ripstop on the outside and inside. If I could get something lighter, I would use it on the inside.
With synthetic insulation, I think the only consideration for the inside fabric is something to keep the insulation from snagging on you and your clothing. You might even consider non-woven material.

http://www.kitebuilder.com/catalog/product_info.php/cPath/24_108_132/products_id/1119?osCsid=78e5084e2847398b482079293237bc25

I get the impression that its waterproof (zero porosity is what they say). But having never used it or seen it I can't coment. However if it is, it may be a nice cheap solution to really light tarp and pack fabric. And it it can stand up to kite flying it must be reasonably strong. I might just buy a few yards of it and see how it goes.

I bought 10 yards of this material to play with. The true weight is about 1.14oz per (real) sq yard of (36" by 36"). This stuff is good for a lot of things and at $3.00 a yard it is very cheap. It is more or less waterproof. I say more or less because in a heavy rail it will mist through. It gets what looks like condensation on the inside. I know someone who made a tarp out of it and another person who used it for a pack.

Bill, how would you compare that stuff to working with Cuben? to Sil Nylon?

darn double posting on refresh...

Edited by jdmitch on 10/04/2005 15:13:08 MDT.

Just don't use ripstop... I have found it in fact rips all too well.

So Bill, what is your source for the light silk?

I'll save Bill the trouble since I've asked that question a lot and so have others on other forums.

www.thaisilks.com

chinasilks - habotai 21H is 0.57oz on Bill's extremely sensitive scale

I think the 26L is about 1.05oz

if you search the forums for silk it will show up in another thread.

Dear Post Anonymously, I have posted the place where I get silk in many Anonymous places. I am surprised you haven't run into it. Check out all your old Anonymous hideouts and you are sure to turn it up.

Jacob you type to fast. But that is Ok.

Edited by bfornshell on 10/26/2005 21:41:39 MDT.

This is a general question to everyone but again I think guru Bill holds the answer.

I just ordered enough yardage of the 21H to make up my two quilts. I got my samples this morning and whilst the silk is very light weight. I think If I baby it it will last me long enough for new technologies to advance in other fabrics. However the real question is do you think I could use a wash in or spray on DWR to give this fabric a bit of water shedding capability. If so which is the best to go with? Most require the fabric to be tumble dried do you think silk will stand up to this on a low heat?

I use a bivy anyway but if I wanted to ditch the half lb bivy I would like just a little protection from water.

thanks