I was concerned myself at first and I did some light research and now I won't say I'm confident enough to write a paper about it, but, from my understanding, I'm confident enough to build it for myself. As you might have found out, the cup is made out of Alumina.
Here and
here you can find its physical properties and
here, you can compare it with titanium. I might be misreading these since I'm not a scholar, but the material appears to be as hard as titanium so it won't flake, scratch or produce dust and we are using it at very low temperature compared to what is it supposed to be safely exposed.
the ones I have are way smoother and nicer looking then many of the pictures I’ve seen
Mine too look pristine, super smooth pink surface everywhere on the outside. No dust either... The other user post worried me a bit, so I tried my best to produce some with another cup of my dozen and couldn't
. Tried with various things from sharp tools to sanding paper made with aluminum oxide (the same stuff that the cup is made out of), the tool would leave marks that I could sand off but the sanding paper itself wouldn't do anything, not even make the surface a bit rough. The only way I could produce some dust/flakes is when I broke one hitting it with a hammer.
Thinking about that other guy and all his troubles and I'm very skeptic of his experience. Either he bought defective cups, hit them with a hammer to fit in the coil or is straight up lying (which wouldn't be surprising since other details are sus too like the abv experience and the complain about having to hold it; which is something he
had to know before hand since every video about it show ppl holding it.