After all the high praise for Stretch Magic around here, I went out and bought some. But now I'm not so sure.
Stretch Magic seems to me to be a little "twangy" (think elastic band twang). Perhaps it's the size I got. I ended up with the 1.5mm variety. Since a portion of hard drive noise is high frequency, I can't help but wonder if it would transmit along the more taught piece of SM (the part carrying most of the drive weight), and get picked up by the drive cage. Also, in my setup, there are fans mounted in front of the cage, and I can imagine SM singing in the breeze. There is probably not enough air moving to do that, but it did cross my mind.
I've also been thinking about fabric store elastic. Conceptually, elastic made for clothing isn't made to be under constant stress. For example, you might wear a piece of clothing 16 hrs a day maybe two days a week. The elastic would remain in its relaxed state 80% of the time.
I'm leaning towards medium duty shock cord (ie not the thinnest - next gauge up). Thats the stuff you'll see in most newer tent poles. It's made to be under stress all the time, is a smaller diameter than Bungee thus more easily strung and knotted. In the tent pole example, they stay disassembled 99.9% of the time, thus leaving them under tension. Even when the pole is assembled, the shock cord is still under stess, just less than when the pole sections are separated. And the stuff in my tent poles has stayed stretchy for years. While it too can twang, it's a much lower tone than SM, and I think it would require hurricane force winds to make it sing in the breeze.
Maybe it is a matter of semantics. Perhaps the fabric store elastic Mike suggests, in reality has exact same material specifications as shock cord, and merely dual marketed.
Are my thought processes out of whack, or do they make logical sense?
Not whacky, reasonable thoughts.
No comments on stretch magic, never used it.
Clothing elastic -- I've used miles.
Going back to the very first elastic suspension I wrote about in 2002, I examined it about a year ago and found that much of the stretchiness had gone, some of the elastic strands were actually broken, and my HDDs were hanging mostly because the external woven fabric kept it all together. That woven fabirc is tough, as I'vge written many times before. The vibration isolation was still not bad, though. 5 years and still more or less working seems a pretty good lifespan for a buck's worth of material.
In thinking about how to avoid wear and tear on the elastic
, I've come to the same point of view as you, chapmani: Keep the tension on the material to a minimum.
These days, use more loops that I used to (3 instead of 2) and keep them under as little tension as possible. Then when the HDD is inserted, there is a bit more sag than before, but as I don't move the computers around much, this is no big deal. It probably gives slightly better vibration isolation, tho that was never an issue even with the material stretched much tighter.