In a message dated 10/17/98 10:02:09 AM, lbowles_at_bmts.com wrote: <<I used a vapor barrier liner (VBL) for the first few nights of a snowshoe trek last year. ...... I guess I have to make my own. >> do you know what they're made of? maureen *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Bennybamba_at_aol.com wrote: > > In a message dated 10/17/98 10:02:09 AM, lbowles_at_bmts.com wrote: > > <<I used a vapor barrier liner (VBL) for the first few nights of a > snowshoe trek last year. ...... I guess I have to make my own. >> > > do you know what they're made of? According to my MEC catalogue, they are made of PU-coated nylon. I may get arounf to buying some or I may simply use some 4 mil plastic & duct tape & mutter about the feel & sound of it. I gather that VBL's don't have a zipper as moisture will escape through a closed zipper & could dampen the sleeping bag in that area. They do have a drawstring. -- Lloyd Bowles The Mad Canoeist "Keep the open side up!" http://www.fortunecity.com/greenfield/clearstreets/358/index.html *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Lloyd Bowles wrote: > According to my MEC catalogue, they [vapor barrier liners] > are made of PU-coated nylon [polyurethane-coated nylon]. I may > get around to buying some or I may simply use some 4 mil plastic & duct > tape & mutter about the feel & sound of it. I agree, plastic is cheap, and apropos for the very few times I might use a VBL. Probably more susceptible to puncture than fabric, though. Another poster (Rich Mitchell <mitchelr_at_ucs.orst.edu>) mentioned that PU coatings will eventually emulsify if kept wet and warm (and, in contact with the oils, acids, etc., from body perspiration?). This jives with my experience with various items of PU-coated raingear, over the years. I don't know the exact mode of degradation, but the PU coatings definitely fall apart within a couple years of frequent use. Anybody (beyond Rich) noticed this with VBL's? Rich also claimed to have good luck with silicone-coated fabric as a VBL, and referenced some Stephenson-manufactured gear, I think. I am unfamiliar with the properties of silicone-coated fabrics, and would not know where to get them. Anybody know? -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Dave and list: >Another poster (Rich Mitchell <mitchelr_at_ucs.orst.edu>) mentioned that PU >coatings will eventually emulsify if kept wet and warm (and, in contact >with the oils, acids, etc., from body perspiration?). >I don't know the exact mode of degradation, but the PU coatings >definitely fall apart within a couple years of frequent use. Anybody >(beyond Rich) noticed this with VBL's? I had a Stephenson tent and sleeping bag that bit the dust after a few years service for me (5 or 6 max?). Richard loves his Stephenson tent (dunno if he has a bag from them or not). Mine started leaking after a few years, and I sent it back complaining. They recoated it and it helped for a while, but not very long (maybe a year?). I'm hard on tents and replaced it with a Sierra Designs and more recently a Mountain Hardware. The vapor barier sleeping I got from them was really nice. Again, though, after a few years, the coating started flaking off and small pieces would be stuck all over me when I get up in the morning. I retired the bag after the down loft was reduced enough to not be effective any more. I'm sure the VB was not very good any more either, but didn't try to really test it. >Rich also claimed to have good luck with silicone-coated fabric as a >VBL, and referenced some Stephenson-manufactured gear, I think. They may be using newer materials, I don't know anything about their newer stuff. The bag and tent I had of theirs was bought about 1972 all replaced before 1980. I'd also be interested in info on such stuff if anyone knows. Good luck, Hank Hays *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
A vapor barrier is a diaper for your sleeping bag. It is a thin waterproof bag which fits between you and the inside of your sleeping bag. It prevents your perspiration from getting into the sleeping bag. Richard Culpeper www.geocities.com/~culpeper ---------- > From: Bob Denton <BDenton_at_aquagulf.com> > To: Paddlewise (E-mail) <PaddleWise_at_lists.intelenet.net> > Subject: RE: [Paddlewise] Re: Sleeping bag liners-VB > Date: Tuesday, October 20, 1998 4:22 PM > > What is a Vapor Barrier? > > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
We can add a bit more to the VBL description. In a typical night while at sleep an adult male looses water via insensible perspiration and respiration. To transform water into vapor requires heat energy, between 2,000 and 4,000 BTU per night depending (body size, humidity, metabolism etc.). This is a source of dehydration but the heatr loss is the most crucial factor. It takes 55 btu to make a cup of coffee on an average cool camping morning. (Dave Kruger can add the details). 2,000-4,000 BTU is a lot of heat. So the VBL does two things: first it saves most of that heat -- once the ambient humidity next to the skin reaches 95% or so perspiration stops, so no more water need be turned into vapor, so no more heat is lost. If the VBL is close to the skin only a small space need be kept humidified. Second, perspiration without a VBL passes though insulating layers until it reaches colder air, like near the inner surface of your sleeping bag, then recondenses into liquid or freezes into solid form. Now you have an ice filled sleeping bag. The same thing happens in mountaineering and ski touring boots which is why many of us used to wear plastic bread bags over our liner socks and under our thick Ragg socks on winter climbs and ski tours. The practical effects of VBL are, in our experience, not a 5 or 10% increase as was suggested by another poster but a 10 or 12 *degree* F improvement in the comfort rating of our bags (consistent over 20 years in varied conditions) not to mention keeping the insulation dry and therefore as lofty on the second and third days out as on the first. Even kayakers and canoefolk sometimes uses VBLs. I once led a group of novice paddles to the Broken Group in March. A rare calm day made our crossing to Hand island uneventful but the temp dropped to 10 F that night and many equipped with summer habits and gear were cold. I gathered the frigid folk together around 10:30 and gave a little VBL lecture. Basically I told everyone to strip to there long johns or a thin inner layer, then put on their rain coats and pants (tucked into socks). We used water proof stuff sacks and the like to cover feet. Then everyone got "dressed" again in pile and other insulating layers *over* these impromptu VBLs. All but one unbeliever slept fine from then on. I had my trusty Camp 7 commercial VBL and was happy as can be. Happy paddling and warm ski touring. Rich Richard Culpeper wrote: > > A vapor barrier is a diaper for your sleeping bag. It is a thin waterproof > bag which fits between you and the inside of your sleeping bag. It > prevents your perspiration from getting into the sleeping bag. > > Richard Culpeper > www.geocities.com/~culpeper > > ---------- > > From: Bob Denton <BDenton_at_aquagulf.com> > > To: Paddlewise (E-mail) <PaddleWise_at_lists.intelenet.net> > > Subject: RE: [Paddlewise] Re: Sleeping bag liners-VB > > Date: Tuesday, October 20, 1998 4:22 PM > > > > What is a Vapor Barrier? > > > > > > > *************************************************************************** > > PaddleWise Paddling Mailing List > > Submissions: paddlewise_at_lists.intelenet.net > > Subscriptions: paddlewise-request_at_lists.intelenet.net > > Website: http://www.gasp-seakayak.net/paddlewise/ > > > *************************************************************************** > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** -- Richard G. Mitchell, Jr. Department of Sociology Oregon State University Corvallis, OR 97331 U.S.A. (541) 752-1323 phone/fax mitchelr_at_ucs.orst.edu *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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