Glass hole cutting

[matt2939]

Can you give me your opinion on if these two holes are okay to put a bulk head on and use?

 

[matt2939]

The first hole I cut slipped right as it was going through the other side and chipped the edges

 

[jgraz]

The second hole looks great. The first will probably be ok too, assuming those chips aren't too deep. I did something similar when drilling a tank a while back and I simply added a bit of silicone to the gasket and never had an issue.

 

[TanksNStuff]

If the chipping is on the outside, it's no problem at all. If it's on the inside, there may be some leakage past the gasket. Using silicone between the gasket and glass (as John suggested) might work if it's not too bad.

If it is on the inside, put the gasket on the hole (without the bulkhead) and see if the chips extend beyond the diameter of the gasket. If they do, then the small openings will be enough to cause a leak. If the gasket covers all the chip marks, the pressure of the bulkhead should seal the water from the outside rim of the gasket and not get into the cracks at all. I would still put a lil bit of silicone in there to be safe though.