Drilling large hole through thick glass

[DKAudio]

I want to add a over-flow to my fish tank. This will use a shower drain installed on the back wall of the tank near the top. It will carry water down to my sump (filter and water holding area) underneath and then be pumped by up into the main tank.

I am going to use a 2" shower drain.

My question is, how can I drill through my tank safely? I believe it is 1/2" thick, not sure if it is tempered or not.

Glass shops will do it for around $40 but then I have to empty the tank, get my fish out to a safe area, find a truck to use, etc.

[thedcdude]

My advice:

Spend $40, empty the tank, get the fish out to a safe area, find a truck to use, etc.

You're going to have to empty the tank to drill the hole anyway, right?
How much will it cost to replace the tank if the glass shatters.
$40 is a bargain.

[HayZee518]

if the drill you use doesn't spin true the glass will shatter, if the speed is too fast the glass will shatter, if the grit and water mix isn't right the glass will shatter.

[DKAudio]

It appears (according to Oceanic) that the back pane is plate, not tempered. I think I will get a diamond hold saw and give it a go. They make guides to keep the saw true, I will just let the saw do the work and not push at all. Thanks

[mrcaptainbob]

Plate glass can be cut with heavy shears or tin snips while submerged in water. Crayon mark the outline (can be curved or wavy) and snip away. Lay several sheets of newspaper in the bottom of a tank or sink, fill with enough water to cover your hands, scissors and that part of the glass you're cutting. When finished, drain the water, roll up the paper with the glass shards and toss it. I would think the same could be done for drilling a hole. Experiment first (use a BATTERY drill!! {No electric cords!!}) and see if that would work....