Hey all, firsty, i love the forum! I could spend hours on here. im new here, so sorry ive done something wrong, like putting this in the wrong forum, etc, (please tell me if i have!)
Ive recently been looking at an upgrade to my bivi, a goretex ex military drawstring hood type one (very lightweight......) and in my quest, ive noticed that no one seems to sell a bivi with the size, shape, and features that im after for the price limit im bound to. So, naturally, i want to plunge into making one with my only experience of sewing being leather work and some gear repairs.
Ive got a general idea, and ive noted down some sketches for plans and ideas and some materials research of what is lightest/ most durable/ water proof/ breathable. Id like to have a mozzie net, a zip or some way of sealing myself in but not having to deal heaps of condensation, but with in not too fussed about a hoop though! Id be going for a rab alpine, or msr bivy sorta design i think ultimately. Any advice or guidance would be so helpful as im not experienced in MYOG projects!
I haven't tried any of this, but Will has a really high reputation in ultralight and lightweight backpacking circles. At least the material is inexpensive enough that you can both use it for practice and actually try it in the field!
Edited by OregonMouse (04/04/1606:27 PM)
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey
Keep in mind that there are at least 12 types of Tyvek, the one that is breathable (for humans not houses...) is the 1443R also known as Cloth Tyvek or Kite Tyvek. 1443R is water resistant but not waterproof particularly when in contact with another surface . I would use the HomeWrap* (or silnylon) for the bottom and 1443R for the top. Take a look here : http://www.milesgear.com/UberBivy.html * to get rid of the noise of new HomeWrap just roll it up and twist it
Wow, thanks! much appreciated, i only thought there was the single house wrap tyvek so i didnt look into it! If i used say, goretex (3 layer) or pertex (shield+ or endurance or something) instead of tyvek, would that be more suited or would tyvek still be the best? I mean i dont think ill get any lighter than tyvek, but on grounds of waterproofing and breathability.
I made myself a bivy using 1443R for the top part and a type of HomeWrap for the sides and bottom. Only used it at home just to see if it works, for breathability, and it does but it is a bit fragile and I would not use it as a stand alone bivy but under a fly so that all it would have would be sprays not direct rain. As a tent fly 1443R works a bit better at holding rain if there is no contact with it (you pressing against the walls) still it isn't waterproof just water resistant. BTW one of the reasons I made that bivy was because Tyvek can be glued with PVA (Elmers glue) so no stitching required.
I made one from the clothing type 1443R and have spend maybe 10 nights out in it, the last time the night before last in SE Oklahoma. It weighs about 7 ounces. I am very happy with it. I don't think it would keep me as dry as a real bivy would in the rain, but it did keep me dry on a trip in the Sandia Mountains in New Mexico where the only other person in group not under a tarp woke up soaked from condensation. It got colder than expected that night and I pulled the flap over my head and didn't make any effort to direct my breath outside, still there were no moisture issues. I also used it as a shawl in an unplanned rain/hail storm on Charleston Peak near Las Vegas, it was much more comfortable and easier to regulate temperature with than a plastic groundsheet has been in similar situations. It's also held up well with even though I've never used any kind of ground sheet under it.
The design is very simple: 2.5 or so feet wide by 7 feet long, with an extra-wide floppy section that I can pull over my head. The idea was to prop the floppy section up with something but I've never done that outside of backyard testing, I just use it as a blanket.
I did a test with a drinking glass and a rubber band to see if the material would leak and it didn't after two days. If I make a ball of the material and fill it with water it feels moist, though, even though none will drip out. I think that that's just the way a breathable material is: surface tension keeps water out unless you touch it, like old canvas tents, and in a bivy you'll be touching it so I suspect water would eventually get in in a decent storm. I went out in the yard once during a light rain and read for a while and was OK but I wouldn't want to spend much time like that, especially if it's more than a few degrees warmer or cooler than ideal conditions. For me it's primarily protection from condensation and adds some warmth if necessary. It also doesn't weight much more than an over-sized ground cloth and I can't slide off of it.
A buddy of mine just bought an oversized painting suit of what seems like the same material at Home Depot for about $10 and plans to rip the seams in the legs and glue them to together to make a mummy-shaped version. I'm not sure how that will work but it's a cheap, quick way to get ahold of some material.
Loc: Central Illinois near Springfi...
Originally Posted By 41253
A buddy of mine just bought an oversized painting suit of what seems like the same material at Home Depot for about $10 and plans to rip the seams in the legs and glue them to together to make a mummy-shaped version. I'm not sure how that will work but it's a cheap, quick way to get a hold of some material.
This brings up something a bit off topic, but maybe worth exploring: Tyvek clothing for wind protection. I've got some Tyvek hooded jackets and pants that we used when working in a particularly greasy job (think Mike Rowe, Dirty Jobs). I need to get some of that stuff out and see what it weighs. I haven't priced any lately, so I don't know how it compares to nylon and polyester wind shirts and pants. I know that it won't be waterproof, so rain gear is out.
If it's not too heavy or pricey, it might be worth a look.
Thanks!i do see why tyvek is so appealing for myog bivis now! Ive been fiddling around with designs and ideas, and ive come to a design with is similar to the borah snowyside bivy, just with a centre zip and double opposing storm flap and chest zip. Ive seen something similar with tyvek, so ill go that route i think. If im not happy with the properties of tyvek (id like t use it as a standalone shelter, so for aumn/winter it might not be suitable) then ill do the same in a goretex or event if i could get hold of some (the uk has barely any suppliers of goretex, let alone Event).
I have a rab alpine and have had good fun with it, only problem was the silnylon on the base wore out, and i cannot find any seal tape to stick to silnylon, i have been told there is one that does.
That is an important point as i found when i made my own bivy, make sure your tape (if you use tape) sticks properly, pvc i think is the norm. Sone material as i found out gives the impression of sticking until you fold it and use the bag, then it peels away, and your left miles in the sticks lying in a puddle !
The 3 layer goretex is good, fully sealed i still got condensation, the down bag eventually rotted around the face leading to less loft, if i wanted to breath into the bivy i would not make it from anything else, but if your breathable material is any good (and the budget stuff has come along way in 20 years) it should suffice for all other
Loc: Kitsap Peninsula, WA
Just a few comments: i have a friend who made a Tyvek bivvy and he said he had way too much condensation while snow camping. Exact material unknown, probably house wrap. I have a three layer gortex bivvy and it works. It has kept me dry in a few rain storms and I have never felt calmy or had condensation. However.....it weighs a pound and a half. I have a tent that is much more roomy and comfortable that weighs 2 pounds. And...most of all, I have decided that if it rains you need a tarp in addition to your bivvy because you need a place to change clothing, cook, sort through your pack and such. If it is really raining you can not do those things with just a bivvy. So the weight of an UL tent is equal and you have a better environment to wait out a storm. also, what do you do in a bivvy if it is really raining and you need to pee at 2 AM?