Just throwing this out there, what is the cheapist waterproof fabric, breathable is a must also. I am looking to make a varity of things from this fabric (backpack, hammock, jacket, tent, or anything else I deam important). Thanks and sorry this is vague, I'm just looking for opinions.

Edited by dufus934 on 02/19/2008 15:24:47 MST.

why would you want a breathable pack?

I have found breathable stuff at Joann's. It looks and feels like the 1.1oz I've used. I've made wind shirts and quilts with it and like it very much. Both times i got it for $2/yd (my scale isn't accurate enough to check if it is actually 1.1oz yd2)

I've heard of people finding silnylon at Walmart for $1/yd, i was not so lucky but i did find some 1.1oz with some type of treatment on it for $1/yd, it's not breathable and is waterproof, though not siliconized so i don't trust it for a tarp, but plan to use it for a pack.

If price is the biggest factor for you you're stuck scrounging the Walmarts and Joann's of this world. Check Noah Lamport for the best prices (under $3/yd) on 2nd silnylon

Edited by MarshLaw303 on 02/19/2008 19:06:21 MST.

In some gear you mentioned, I think it would be much better to use just waterproof fabrics, especially if it should be cheap.

My first concern is durability of the fabrics, for example in a pack. I don't have good experience with cheap WP/B fabrics (nylon with hydrophilic PU membrane, what is probably the only option that can be found cheap). For examples, trousers made of such a fabrics started to leak at knees almost immediately. On the other hand, a more expensive fabrics may work much better. I have made a pair of socks out of 2.5 layer goretex paclite and they still work fine after a year of occasional use. I can hardly imagine stressing the fabrics more than using it for socks.

Secondly, the WP/B fabrics doesn't work just in one direction. It simply transfer water from the side with higher potential to the other one. In clothing, it is usually warmer inside, and this gradient helps to transfer the moisture out. If you put dry gear in a WP/B backpack and subject it to wet conditions, the humidity gradient will slowly (very slowly) transport the water into your pack. I'd prefer just waterproof fabrics here.

To conclude, it would be much better to use appropriate material for each piece of gear, WP/B is not universal solution to everything.

I realize that the question might have been a little vague and dumb in parts (a breathable pack), but what I was wondering is if there was a fabric that I could just buy in bulk that would suffice for all of these applications.

Silnylon is probably the best cheap waterproof fabric, although it is not breathable. Most applications do not need to be breathable--backpack, hammock, tent, etc.
Noah Lamport has the best prices I have seen for silnylon 2nds for under $3 a yard with a 10 yard minimum.

Ripstop nylon from Walmart or anywhere else you can find it for $2 per yard is OK for items that must breathe. These fabrics will weigh close to 1.6 ounces per yard. Very occasionally Walmart will have 1.1 ounce ripstop. The only way to tell is to take good scales to the store and weigh it then divide the weight by the width x length. A calculator helps. JoAnne usually carries germent grade 1.6 ounce Nylon 6 instead of parachute grade Nylon 66. Nylon 6 is about half the strength of Nylon 66.

You COULD make a pack out of breathable fabric, but it would need a waterproof cover. For packs, tarps and other items better made from waterproof fabric, careful shopping for silnylon seconds can turn up prices under $6 per yard for 1.35 oz. fabric.

If you really want to have waterproof and breathable fabric, the only low cost option is Tyvek HomeWrap. It's a very good product, great for tarps.

Peter,

You said hammocks don't have to be breathable. I disagree, i am a horrible night sweater and would not like to wake up in my own personal swimming pool every night with a waterproof hammock fabric. I think others would experience discomfort as well, just maybe not as much water (sweat) in theirs as i would have

Sorry, disregard anything I may have said about hammocks. I dont have any experience with them, and inadvertently added it to my list of things that wouldnt require breathability.
Thanks Tim for catching my error.