I'm completely new to the whole MYOG thing. I want to make a bivy sack - I'm thinking sil-nylon floor with Pertex Quantum top (i.e. BMW Vapr). Where can you buy Pertex Quantum? Is there another fabric that is equally breathable? I'd be under a poncho-tarp and need some protection from rain spray.

Any help or patterns on a MYO bivy sack would be helpful!

You can get Momentum90 from thru-hiker.com. Everything I've read shows that it performs as well or better than Pertex Quantum in breathability and waterproofness.
I've been contemplating a bivy too and was planning on using Momentum for it. Depending on the price and availability of Pertex Quantum I could be persuaded to change my mind though. I haven't seen it anywhere online, but then again I haven't specifically looked for it either.

Adam

I'll second the vote for Momentum90 from thru-hiker.

I own a genuine Pertex Quantum windshirt and I have MYOG using the Momentum90. IMHO both are comparable.

I have no personal experience with Pertex or the PERFORMANCE of either fabric, but I DID read this website the other day, and they HAVE compared the two fabrics (about 3/4 of the way down the page on my screen):

http://www.mountainlaureldesigns.com/fabric.php

Also, if you're still interested in Pertex, this online vendor has some:

http://www.justmakeit.com/fabrics/water_repell/index.html

I looked at Pertex for the shell fabric for a down quilt I'm going to be making. But at $20/yd I just couldn't justify the cost. I went with Momentum, and then found that link comparing the two the other day. Boy am I glad I didn't shell out the extra cash!

Thru-Hiker.com has Momentum90 for $11.95/yd (personal experience, the purple is a great color, but then, Paul Nanian over at Thru-Hiker.com says that all the Momentum colors are fantastic):

http://www.thru-hiker.com/breathable-fabric.html

Hope this has been helpful...

Edited by cowboisgirl on 08/21/2007 08:34:58 MDT.

Hi Sharon,

Coupla things:

First, see this thread for a discussion of the Pertex source you list. Pertex is a company that makes a pretty wide range of technical fabrics, and what is listed on the Textile Outfitters site apparently isn't Quantum.

Next, check out this thread, this thread, and this post in particular from Ron Bell of Mountain Laurel Designs. Might be helpful!

Questoutfitters.com has a bivy pattern. Look under "patterns" and then tents/shelters".
Observations about the above pattern. There is a lot of material in the head area. Its rectangular shape makes it easier to sew, but a rounded head would save material and weight. Rather than have the zippers go up the sides of the head box, have a zipper go straight across the top, and another zipper, or an extension of the same zipper, go maybe two feet down the side. Waterproof zippers would eliminate the need for flaps over them. Also it does not have the option of rolling back or removing the mosquito netting. The body of the bivy looks good. Remember, too, that a bivy has to easily fit over your sleeping bag, and consider the loft of the bag you are most likely to use with it. In other words, the bivy needs to be a "baggy" fit, not a tight fit. I actualy have Momentum90 from thru-hiker and silnylon waiting to be made into a bivy. Momentum is soft, with a very nice feel to it. The red looks great with black silnylon! The shiny side goes on the inside as I was advised at thru-hiker. The material is sold by the yard, not segments of yards. I think I will be able to make the bottom one piece with a curved head box included. I will consider having the top piece taper in at the bottom, but include a circular "head" which will become part of the foot box. Maybe not, however, because I do not want the fotbox too tight as mentioned above. I also want to be able to roll back the netting and close it with a zipper, not velcro. I might not even add netting.

Edited by rambler on 08/26/2007 04:51:12 MDT.

http://www.sixmoondesigns.com/ultralight/myo_Meteor.asp

I've always seen the Six Moon designs Bivy pattern as a perfect meld of bug bivy and a water resistant bivy. I reckon that if you use momentum 90, spinnaker or sil nylon, and nanoseeum from thruhiker.net, you should be able to make it for about 6-8 oz