I just received some fabric I ordered for a couple of projects, and am pretty disappointed, and wondering if anyone else has run into this.
First, I ordered some 400x300 nylon/polyester "diamond ripstop" and discovered that it's ripstop in one direction only. That is, it tears quite easily in the longitudinal direction, but going across the fabric from selvage to selvage, the ripstop grid stops the tearing.
Before I go on, I should mention that the way I'm testing these fabrics is by making about a 1" cut, then tearing it by hand. There's a machine for this, but I'm not quite that well-equipped.
So, out of curiosity, I also tested the other fabrics I ordered, namely, 1.9oz coated ripstop nylon (2 colors), 1.9oz silnylon, and 330d Cordura.
The Cordura was fine.
All the remaining fabrics ripped easily in BOTH directions! So I tested some other 1.9oz ripstop I'd had for a while (from the same source). It tore easily, too. Then I tested a piece from a different source (The Rain Shed) and as soon as I hit one of the ripstop threads, it wouldn't tear any further (as it should be).
Upon further examination, it appears that the easy-tearing fabric was just woven to look like ripstop nylon. It's a little difficult to tell on coated material, but with a jeweler's loupe you can see it if you sort of shred the fabric.
So, is this common now? I haven't bought any ripstop fabric for a while.
I'm not naming the source until I find out more. I mean, if everybody's selling this pretend-ripstop I can't blame them too much. They are one of the major suppliers. I did email them my displeasure, though.
Later...I checked a few older pieces of 1.9oz ripstop, both coated and uncoated, and got the same results. That is, they tore easily once cut. So, I've probably used this material in several packs without realizing it. I've also determined that I can't always tell, even under magnification, which is the real thing. It occurs to me that the difference could be the type of nylon, i.e., the tenacity...whether its nylon 6 or nylon 6/6 or whatever.
I realize that tear strength isn't the only consideration in selecting fabric, but it's driving me nuts anyway.
I haven't the foggiest idea, though I remember reading on another forum that some DIYers are not big fans of the diamond grid. They felt it was only added for looks and that it added weight to the fabric but did not significantly change the mechanical characteristics. Perhaps they had a similar experience to you.
I would consider Richard Nisley the ultimate expert on this. I think this is his website: https://1drv.ms/b/s!Ai3ydnM5MNiZlWn-bNAt1Uuy7T1V
Though that link doesn't work from my office computer (probably a firewall issue).
I called The Rain Shed, as they've been very helpful in the past, and spoke their buyer, who said I'd be welcome to test a few samples. I hadn't been there in a few years (used to live close by, but no longer) so I drove down to Albany.
She let me tear fabric to my heart's content, which I much appreciated. She also passed along some helpful information, based on her experience. Understand that I'm not quoting her directly, and I don't want to put words in her mouth. This is just my understanding.
Apparently, in years gone by, any fabric labeled, say, "1.9oz coated ripstop" was likely to be pretty much the same. These days, manufacturers use different weaves, materials, processes, etc. in order to cut costs and appeal to different markets. At least some "ripstop" weaves are mostly cosmetic.
Also, fabric normally tears more easily in one direction than the other. I guess I didn't realize that.
I tear-tested these while I was there:
400x300 diamond ripstop - looks identical to what I purchased elsewhere, and tore in the same way, that is, easily in the longitudinal way (warp, I think) and very difficult in the other direction (weft).
1.3oz (30d) silnylon - very difficult to tear in either direction. This is "silicone impregnated nylon." There's also silicone coated nylon (coated one side), and nylon coated on both sides with a combination of silicone and polyurethane. Both of these tore pretty readily, and were difficult to tell apart visually from the impregnated nylon without looking very closely.
70d silnylon (should be about 1.9oz, but not specified.)- tore pretty easily in both directions. I think this is coated, not impregnated.
70d (1.9oz) PU coated ripstop - tore fairly easily, maybe a little tougher than the stuff I had ordered before, but not much. As before, I couldn't really detect much of a rip-stopping effect.
210d coated oxford - tearable, but of course tougher than the lighter material. Quite a bit tougher than some of the same denier and weight that I used to have. That stuff was so weak I never used it, and assumed it was to be avoided. Maybe not. I have a piece of 210d ripstop (that I got from RCT Fabrics before they quit business) and it's very hard to tear. I mentioned this to the lady at the Rain Shed (stupidly didn't get her name) and she said it was probably a special order made for some manufacturer.
So, I guess what I learned is that it's kind of a crapshoot, and I should worry less about it. Still, it irritates me that you can buy "ripstop" material that isn't really ripstop.
I bought some of the 210d coated oxford, and in case anyone's interested, it's 2.95 oz/sq.yd. The 400x300 diamond ripstop is 4.56 oz/sq.yd. Measured in a highly scientific manner with a tape measure and a postal scale.
Interesting that the 210d oxford weighs only slightly more than the 70d 1.9oz PU coated ripstop (2.7oz). Maybe the coating on the 70d is that much heavier.
Also I notice that some web sites (like the Rain Shed) are listing fabric weight by the linear, or running yard. I wish they wouldn't do that. It frightens and confuses me.