Hi all, I tried glass etching at room temperature with 25% fluorosilicic acid using photoresist as a mask. But to my surprise it is not etching the glass even after an hour. The glass I used was pyrex 7740. If any of you have successfully etched glass with fluorosilicic acid, please suggest me the exact recipe. Thanking you all in anticipation, Keyur Shah Keyur Shah PhD student, CBME Department Stevens Institute of Technology Castle Point on Hudson, Hoboken, NJ 07030. Web address : http://attila.stevens-tech.edu/~kshah5