G'Day
I have been thinking about making a bivi to use in my cape and I was working down the line of silnylon bottom, momentum top but I want the foot area up about 300mm to be waterproof. There are a few manufactures that already do this. The problem is what to use. Does any one know of a suitable lightweight WPB material I could use? It seems the name brand products are un available to the punters so perhaps a generic type might be available. The fabric sites I’ve tried have some but it’s difficult to gauge the weigh but I suspect it’s heavy.
If any one has had any experience or could suggest anything and where to buy that would be a big help
Thanks
Darren

Brian Maynard was advertising 3 yrds of e-vent on gear swap a week or sdo back.

OWFINC.com sells epic. It is under 2oz yd2

-Tim

Tim
Have you had any experience with epic? I am concerned about the momentum being continually brushed or pressed against the heavy condensation on the inside of the silnylon. Also moving around and inadvertently putting my feet near the edge in heavy rain. Do you think Epic would wet through
Darren

If it's only about a foot maybe you could get by with something that doesn't breath. You could probably make something simple just to test it out.

you need it to breathe. It's over your feet, they need the air. Once a friend of mine put the very foot of her bag in a garbage sack to help it stay dry, SOAKED the next day, yet no water in the tent. She couldn't figure it out. Your feet pump out moisture, i wouldn't risk it.

I used EPIC on a down quilt i made for ROG (maybe he'll comment on it) but i only sewed it up, i didn't get to use it. I have a bit left that i'll use for something i make this winter. But i don't know much about it yet. It is pretty light, only a bit heavier than 1.1sil. It was easy to work with and seemed to breathe well when i did the breathing test.

-Tim

One of the things I thought of would be to wrap the silnylon around the foot box but then put a small vent in the end. I could overlap a small strip about 2" then sew vertical in lines to stop the flap lifting. This would allow a bellows effect when you rolled around in the bivy. A bit like the vent on the back of cheap pu rain jackets. The majority of the top would be momentum, there would only be a small overlap of silnylon so the weight gain would be negligible.
Any one any thoughts
Thanks
Darren

The epic at the foot and head of the quilt Tim made me breathes nicely, no condensation issues here.

My first MYOG project was a bivy made of epic (top)and sil 1.1.(bottom)
Got pattern and material from http://www.owfinc.com/.
Turned out great, later added a water proof zipper down one side from Thruhiker.
Condensation has not been a problem, usually use a tarp when heavy rain is coming down. Light rain and heavy dews, epic was fine. I did have condensation freeze up on one outing, I set up for the night in a low lying area that was basically very wet and the temperature dropped down quickly over night into the mid 20's and had frost on the inside of bivy. I quickly learned not to sleep in a mud hole! I would say the epic is a good choice and is strong enough not to easily get torn.

I am going to give the epic a run but i noticed have a few types in the light weight range that OWFINC sells. Does any one know which is best of the light ones they sell.
Thanks
Darren

From what I've heard, Epic is good for tents that will see short spats of rain, but will wet out after a few hours of a heavy soaking. Since the foot section of a bivy probably won't see 5 minutes of heavy soaking, I'd say go for it. I have only seen Goretex Paclite yardage available from OWFINC and Oware.