Glass drilling question

[Ramesh]

I had my new 500g tank drilled today and added two more 50mm or 2" holes for bulk heads and have a question about shells.
The bottom hole has a very shallow shell were the drill punched through.
I want to know if this will be a problem.
I am going to ask the guy who drilled them if they need some finishing to smooth around the edges and will it be O.K.
The holes were drilled from inside the tank so the one shell I am worried about is on the outside of the tank.
I think this is a question for chompers.
The bulk heads I use have a very large flange which should distribute the pressure evenly around the hole.
What do you guys think??

 

[hybridtheoryd16]

The rubber gasket goes on the inside and there for any sealing is on the inside. So you are fine. ------A shell on the inside can be tricky if it is bigger than the gasket. But i have made them work as well by siliconing the broken glass back into the shell and then immediately putting the bulk head in place and tightening

 

[Ramesh]

The shell is quite small (3mm) and shallow but I have no experience with what is O.K. and what is dangerous or bad
The gasket on the bulk head will easily cover the area, I just heard that shells were bad that's all.

 

[invisyblegypsey]

he put to much pressure and not enuff coolent

 

[CHOMPERS]

It's unfortunate that many "professionals" never excel beyond amateurism. The shelling is easily avoidable with a little care at punch through. He also could have drilled from both sides for perfect edges. Fortunately the shelling doesn't compromise the glass.

As long as he kept the drill and glass cool through the whole operation, the glass will be fine.