Theory on cracking Vision Egos/Stardusts
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Possibly. But the plastic is pretty tough. When I took apart my first stardust, I grabbed the metal band on the bottom with pliers and tried to pull it off by wiggling the plastic tank. It was very difficult and I had to wrestle with it a long time. In fact, I squeezed the band out of round. Other than some scratches on the band, though, it weathered my assault pretty good. I don't see any cracks.
I've been using them exclusively now for the past 3 weeks and have not had any cracking issues at all. The only problem I have is that I have to top them off pretty often.
I bought one to try and checked it rather frequently for cracks since I had read so much about them cracking. It suddenly developed about a 3/8-inch long crack up from the base as I was rinsing it out with very hot tap water. Since then I've only used lukewarm water to rinse it and the crack hasn't grown. My theory is that cracking can occur because of the differences in thermal expansion of the metal base and plastic tube.
Thermal expansion... interesting. The 1st two I ordered developed cracks, but they were from the early batch. I did rinse them out when I changed juices, but I don't remember if I used HOT water or not. [Ordered these from e-cigexpress.]
I ordered 5 from the last batch and 2 of them have cracks (haven't used the other 3 yet). [These came from GotVapes.] The one with Cherry juice cracked first - enough to suck air. The 2nd one has Spearmint in it, and it has a crack - but not enough to draw air through it. I haven't changed juice in either one, so...
They're all SR rated & have only been used on my 1100mAh eGo clone, so I doubt I've been exceeding design limits.
I ordered 5 from the last batch and 2 of them have cracks (haven't used the other 3 yet). [These came from GotVapes.] The one with Cherry juice cracked first - enough to suck air. The 2nd one has Spearmint in it, and it has a crack - but not enough to draw air through it. I haven't changed juice in either one, so...
They're all SR rated & have only been used on my 1100mAh eGo clone, so I doubt I've been exceeding design limits.
The thermal expansion theory is only partially correct when it comes to cracking in plastics.
1) ESCR is the plastics engineers techno speak for environmentalal stress cracking. Clear plastics such as polycarbonate and acrylic are amorphous in structure as opposed to crystalline; these amorphous plastics have poor chemical resistance. Some flavors, but not all, weaken the plastic which is the reason why only some of you have a problem and others don't. For instance, some fruit flavored juices such as apple really do a number on polycarbonate.
2) Notching, especially with the amorphous plastics, makes the problem even worse. In mechanical terms, a notch or nick in the plastic is a point from which a crack can propagate. It's like glass-also amorphous-which is scored by a diamond wheel tool to be "cut" to size. Normally, these types of notches are created by poor finishing of the part.
Add any kind of stress- heat, chemical, or mechanical- and you have your cracking. In most cases, it does not take much.
Sorry for the drawn out explanation.
1) ESCR is the plastics engineers techno speak for environmentalal stress cracking. Clear plastics such as polycarbonate and acrylic are amorphous in structure as opposed to crystalline; these amorphous plastics have poor chemical resistance. Some flavors, but not all, weaken the plastic which is the reason why only some of you have a problem and others don't. For instance, some fruit flavored juices such as apple really do a number on polycarbonate.
2) Notching, especially with the amorphous plastics, makes the problem even worse. In mechanical terms, a notch or nick in the plastic is a point from which a crack can propagate. It's like glass-also amorphous-which is scored by a diamond wheel tool to be "cut" to size. Normally, these types of notches are created by poor finishing of the part.
Add any kind of stress- heat, chemical, or mechanical- and you have your cracking. In most cases, it does not take much.
Sorry for the drawn out explanation.
this is when us mere mortals tip our cap and say "yeah that sounds right......................i think?"
Yeah, that's what I was going to say too. Amorphous................totally amorphous. 
Thanks, Tony! Knowing the technical term for what one is looking at is always helpful, a Google search for plastic environmental stress cracking turns up all kinds of interesting articles.
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