Quote Originally Posted by raul24 View Post
Phase separation in borosilicate glass. The glass separates into two phases,silicic acid and alkali borate, from being held at annealing temprature for to long. So it will be more prone to breakage and corrosion.
From my knowledge Schott Duran for example adds 2% Aluminum oxide (Al2O3) to reduce the chance of phase separation occurring in it's glass. Any amount over 1% greatly reduces the chance of phase separation occurring in the first place.

I imagine others glass makers would add it as well, because if a lab glass is less chemically durable that is a big problem.

I think if your selling adult toys you should look into having some sort of liability insurance, or at very least have a waiver signed saying your not responsible if it breaks.