How much psi to form polycarbonate?

How much psi would I need to hydroform polycarbonate? Was just looking at a video where someone put 18 gauge steel sheet between a flange and plate about 1" thick and pressurized it with water to create a dome shape from the 18 gauge steel. I'm looking to do the same but with polycarbonate. It looked like the 18 gauge steel formed at around 350 psi. What psi do you think it would take to do the same with 1/8 , 1/4" and 1/2" polycarbonate? Approximately Thanks