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Magnum Bivy Project

5K views 16 replies 5 participants last post by  strongcones 
#1 ·
I recently went winter camping here in Minnesota. We did a two mile hike-in to a small lake and stayed overnight. It was a great time, and I learned that my sleeping setup was just barely good enough for 10 degree weather with 30 MPH winds, so I decided to make a waterproof, windproof bivy cover for my Cabela's Magnum 44 -20 sleeping bag.

I got some really nice marine polyester, some nice 1/2" closed cell foam, a 5 foot YKK zipper, some velcro, and went to town with the sewing machine.

It came out really nice. It's surprising how similar sewing and welding are. I can't wait to give this thing a try!

Here's the photos: http://s125.photobucket.com/albums/p57/ ... 20Project/
 
#2 ·
Very nice. Where did you go? I have a trip planned on the Gunflint for trout fishing in March. I'd love to be able to travel light like that but in order to get my wife to come along the tent has to go too.

Where did you get the marine poly? I have some tears in my boat cover and was hoping to be able to fix it rather than throw it.
 
#3 ·
We went to Glacial Lakes State park. They have a bunch of hiking trails and several hike in campsites. It has really cool glaciated topography.

I got the cloth and most of the supplies at Rochford supply in Minneapolis. http://www.rochfordsupply.com/.

The warehouse they have there is huge. It's a good bet they have exactly what you want. They sell seconds for super cheap too. I got my polyester marine fabric for 3.88 per yard at 60" wide.
 
#5 ·
i camped for years using only a bivy - just a gore-tex bivy with a thermarest inside.

warm and toasty, sleeping on the snow in -30 C weather
\
here is a bivy tip. sleep in front of a small sapling, tie a string to your bivy and bend the sapling over and tie the other ebnd of the string to the sapling. the sapling springs back up and pulls your "roof" up with it - gives you loads more headspace in a confining bivy.

though my sleeping bag would squish up waaay smaller than what your is. bivy = half a loaf of breaed, my sleeping bag was like two loafs of bread squished up.
 
#6 ·
I was planning on sewing in a few loops in the top to do exactly what you describe. Also I want to install some snaps along the storm flap on the zipper.
 
#8 ·
I would not recommend using a bivy that is made from a non-breathable material. Especially in temps below freezing. All the moisture from your breath is going to condense on the inside, freeze, and fall like snow right back on your face, or into the fabric of your sleeping bag, where your body heat will melt it, giving you a wet bag. In a word miserable. I would also recommend sewing a pole sleeve/clips over the head area, this gives you more breathing room, or space to read, write in a journal etc. Really, in warm weather you'll probably be ok, but if you plan to use it in cold weather, that non-breathable material will make for a miserable night.

For the record I spent 60+ nights in my Big Agnes 3 wire bivy last summer, loved it. The top is E-vent fabric, kind of like Gore-Tex but breaths much, much better, not a drop of condensation, even when it snowed 3" on me. And enough headroom to keep my camera gear inside when it storms.
 
#9 ·
It's not really meant as an enclosed shelter, since the upper end will always be open.

I know exactly what you're talking about with the freezing condensation, I've seen it many times and it can get bad. I camped a few years ago in 20 below (F) weather in a tent, and got pretty significant freezing breath, but it wasn't really a problem.

In general I'll use this in conjunction with a 16' square ultralight tarp to block the rain and snow, with the bivy bag under it.
 
#10 ·
Ahhh, I see, really just a sleeping bag cover then, not full bivy sack. Should be no problems then. BTW nice sewing.

Before I got my bivy, 2 summers ago I spent about 20 nights using just a 10'x8' tarp and paracord to rig up shelters. I could usually stay dry, but finally gave up because I couldn't take the bugs anymore. I'd cinch up my mummy bag over my face to keep the mosquitoes out, then my face would get to hot, so I'd open it, then the bugs would eat my face till I couldn't take it anymore, then I cinch up my bag again. It was a vicious cycle. I finally went back to my 1.5 man tent for the rest of that summer.
 
#11 ·
Nice job! I have sewn alot of outdoor stuff. Most of mine was kits from a company called "frostline kits" in Colorado. I don't think they are in bussiness anymore and that's a shame because they had real nice stuff. I have made 2 complete sets(f+r) of bicycle panniers, 2 down vests, 2 HD down parkas, a set of zip off down pants, 2 pairs of down booties for lounging in, and a real nice winterweight polargaurd sleeping bag. Everything turned out nice and I saved lot of money. some of this stuff I have been using for over 30 years and it's still in good shape.
http://www.oregonphotos.com/Frostline1.html
 
#12 ·
would not recommend using a bivy that is made from a non-breathable material. Especially in temps below freezing. All the moisture from your breath is going to condense on the inside, freeze, and fall like snow right back on your face, or into the fabric of your sleeping bag, where your body heat will melt it, giving you a wet bag.
i totally disagree! - i used my gore-tex bivy for many, many nights in as cold as -30 C without the condition you speak of. the zipper was left open a hair so i could breather, and i just laid in the snow. inside the bivy i had a thermarest and a blue foam pad, and my 4 season sleeping bag. laid out right on the snow, no cover - nuttin. sometimes woke up to being partially buried by snow :lol: . would stick a smoke out thru the hole and have a morning smoke still lying there.
 
#13 ·
RodeoRed said:
would not recommend using a bivy that is made from a non-breathable material. Especially in temps below freezing. All the moisture from your breath is going to condense on the inside, freeze, and fall like snow right back on your face, or into the fabric of your sleeping bag, where your body heat will melt it, giving you a wet bag.
i totally disagree! - i used my gore-tex bivy for many, many nights in as cold as -30 C without the condition you speak of. the zipper was left open a hair so i could breather, and i just laid in the snow. inside the bivy i had a thermarest and a blue foam pad, and my 4 season sleeping bag. laid out right on the snow, no cover - nuttin. sometimes woke up to being partially buried by snow :lol: . would stick a smoke out thru the hole and have a morning smoke still lying there.
Ummm... ... ... OK... ... No you don't.

Your not actually disagreeing with me, but making my point. Gore-Tex IS a water resistant BREATHABLE MEMBRANE (which is why it is so popular for outerwear). Plus you said you left the zipper cracked open, which let all the moisture in your breath out. There are many other factors as well, like relative humidity and dew point.

I've spent at least 10 weeks a year, for the past 5 years backpacking, and worked in 2 different gear stores. And I admit that I am a raging GEAR WHORE. I have tried almost every kind of shelter imaginable, from DIY with a tarp and paracord, to snowcaves, jungle hammocks, porta-ledges, several 2p tents, and a couple different bivies. My current shelters are a Big Agnes Bivy, for 3 season alone, or a Mountain Hardware PCT 2P, or an old Walrus 2P (if I expect high winds, or above the timberline) with a friend. For winter it's a Marmot Alpinist 2P, or a snowcave if I want to go light, and I know the snow conditions are right.

Don't want to sound like a know it all, but I do know my stuff when it comes to backpacking gear. :p
 
#14 ·
squatch said:
Nice job! I have sewn alot of outdoor stuff. Most of mine was kits from a company called "frostline kits" in Colorado. I don't think they are in bussiness anymore and that's a shame because they had real nice stuff. I have made 2 complete sets(f+r) of bicycle panniers, 2 down vests, 2 HD down parkas, a set of zip off down pants, 2 pairs of down booties for lounging in, and a real nice winterweight polargaurd sleeping bag. Everything turned out nice and I saved lot of money. some of this stuff I have been using for over 30 years and it's still in good shape.
http://www.oregonphotos.com/Frostline1.html
I wish you could still get the Frostline kits. I packed with a guy last summer who use a 25 yr old Frostlite down bag, he's re-stitched a few seams and added a little more down, but it's still working for him.
 
#15 ·
You know for some reason when I read your origional post I read you were not recomending a breathable material- I skipped the non part.:) I totally take back my last post. You are corect as am I! Gore tex is a waterproof breathable material which is perfect for a bivy also for costs gloves boots gators and more. I'm a reformed gear whore too. My job for many years was a four season wilderness guide. I took groups of young offenders on wilderness trips and still am a commercial multi day tripper guide on canoe trips in algonquin park.

Now I'm just a wheeling whore
 
#16 ·
Sags said:
squatch said:
Nice job! I have sewn alot of outdoor stuff. Most of mine was kits from a company called "frostline kits" in Colorado. I don't think they are in bussiness anymore and that's a shame because they had real nice stuff. I have made 2 complete sets(f+r) of bicycle panniers, 2 down vests, 2 HD down parkas, a set of zip off down pants, 2 pairs of down booties for lounging in, and a real nice winterweight polargaurd sleeping bag. Everything turned out nice and I saved lot of money. some of this stuff I have been using for over 30 years and it's still in good shape.
http://www.oregonphotos.com/Frostline1.html
I wish you could still get the Frostline kits. I packed with a guy last summer who use a 25 yr old Frostlite down bag, he's re-stitched a few seams and added a little more down, but it's still working for him.
Yeppers, DIY is not dead yet and times like this go along way towards reviving that kind of thing. More people should act like Planet folk and take care of their own simple repairs and make some things for themselves. As strongcones has just demonstrated. There is nothing like the pride and satisfaction of making something nice yourself that fills a much needed function. Todays fixation on labels is way overrated. Self suffciency skills are way underated these days. But I have the feeling that is about to change fast! Poor kids like me just got a head start.
 
#17 ·
Damn right, squatch.

BTW I had a chance to get out and test the Bivy, and man does it work slick! Cuts the wind like nobody's business and is easy to get into and out of. It snowed a bit, but no heavy precipitation. Trout fishing opens April 18th though, and I'm heading south east for a couple nights, so maybe I'll get a chance to test it in the rain.
 
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