Well, I finally hit the Wal-Mart Lottery last night. I've been checking the fabric dollar bin pretty regularly and have found some nice stuff. Recently I bought a bolt of nylon in a neat digital camo pattern. It's not ripstock but it's a pretty tight weave. I'm planning on making a hammock and tarp out of it, mostly just for the practice.
Last night I checked and found a bolt of light gray silnylon.:D Of course I bought the whole bolt of 15 yards. It's only 48 inches wide and obviously factory seconds. Doing the blow through test I think it's about 98% waterproof. With a coating of silicon spray it should work pretty good.
My plan with the other material, which is 60 inches wide, is to make a McCat style tarp with an 11 foot long ridge and 7-8 long foot sides. I wanted to make the sides 5 foot from ridge to edge, so I guess the original square dimensions would be 11X10. To do that with the narrower material I'd have to sew three strips of material together. But that would mean there would not be a seam along the ridge but would have seams about 2 feet down the sides from the ridge. Is this workable? Or do you need to have a seam at the ridge? Would a strip of grossgrain ribbon need to be sewn along the ridge to provide extra support if there was no ridge seam?
if i had to guess, i`d say the gray stuff is rip stop w/ a DWR finish. if it`s like what i found there, it`s great for quilts, but i don`t know about spraying it w/ silicon & trusting it to be water proof.
you didn`t say if the camo you plan to make a tarp out of has any treatment that can be seen.
of course you said that you were just making a tarp for practice.
I'd put the seam on the ridgeline.
It very well may be DWR but still a great find. I think most tarps aren't 100% waterproof anyway unless they are true silnylon or coated with pvc or something similar. I don't think my Kelty Noah's Tarp is fully waterproof. The camo material was not coated and will probably make a better hammock than tarp. I did a quick test the other night of the two materials, as follows:
Originally Posted by slowhike
1 square of the nylon camo material sprayed with the Coleman Water Repellent spray (if does not mention silicon on the can).
1 square of the nylon camo sprayed with Camp Dry spray that contains silicon.
1 square of the ripstop gray material with no further treatments added.
Test 1: Sag the material over a glass, hold it in place with a rubber band and pour about a quarter cup of water on it and let it sit. After an hour no liquid dripped through any of the materials but the nylon with the Coleman spray had fibers that were becoming wet. The fibers in the other 2 remained dry.
Test 2: Hold the material tightly over the glass and spray water on it at a 45 degree angle for 1 minute at the kitchen sink. Results: The Coleman treated fabric leaked pretty and had about a tablespoon of water in the glass. The Camp Dry (silicon) treatment had about a half teaspoon of water in the glass. The gray ripstop (probably DWR) only had a few drops of water in the glass.
Conclusion: 1. Don't waste your money on the non-silicon spray water repellent. 2. The gray ripstop I have might work OK in most weather except for heavy or prolonged rain. 3. More testing is necessary for better results.
I have found both gray silnylon and gray DWR at Walmart. Usually the DWR, though.
A question - since silicone only sticks to silicone, couldn't you tell if a fabric was or wasn't silinylon by putting a gob of silicone on one corner? In theory, it should stick if it was sil-nylon and not stick if it is DWR treated.
I just read on Whiteblaze that all walmarts are discontinuing the $1 bin.
That matches my experience, in that, the bin at my "good Walmart" is gone and the clerk said it was cancelled.
Oh Dear!! Where shall we turn for cheap material??
I just went back and reread the white blaze post.
It said the fabric DEPARTMENT (the whole thing)would be eliminated by March 2007.
My walmart eliminated the $ bin during the last few weeks.
Man I might have to go try to stock up. Although I did buy 15 yds last time.
Originally Posted by teblum