Drilling A Tank

[andywg]

Well, I had to drill the new tank for Frog Man so I took a few pictures. This is a 24x15x15 tank that will have a bottom hole drilled with a corner weir (pretty much the standard type). The return will come over the top rather than by another hole drilled as I have tried them and do not like them.

First up get your equipment including the bulkhead and drill bit and mark out where you want to drill (a supervisory cat is optional, but those who have seen my DIY threads before will know that the cats always keep an eye on em when I am building). The drill is just a cheap B&Q battery drill and the drill bit I bought for peanuts (or thereabouts) from this ebay seller.

To get the drilling started, have the drill at an angle, as below. You will need to support the drill with both hands to prevent it biting and trying to "wander off" (just like I am not doing as I am drilling with one hand and taking photos with the other).

As you drill in and the drill starts to cut the glass, you can straighten the drill bit up. I should probably point out that I am drilling the near corner and the other white circle is part of the bulkhead I use to mark the hole position (I never use the gaskets as they have a habit of decaying and/or leaking, i Prefer sealing the bulkhead in with sealant).

I can't show the finished article here because I got flash. I tried to take a photo as the hole was just about to drop, got the bit caught and put a small crack. Nothing major as I just patched over the inside (the cracks just shot to the edge, and the weir will be under less pressure).

Don't let my over confidence put you off. Once you get the drill upright it is just patience. Do not push on the drill, just let it do its thing and occasionally wipe out the glassy clay that forms in the hole and pour new water on.

It really is as simple as it looks above.

PLEASE NOTE

Drilling tempered glass is 99.999999% certain to end in misery and shattering. Don't bother. If you are in the US then there is a fair chance the bottom may be tempered (in which case one can still drill the side for a mini weir). Most UK tanks are not tempered.

I would like to point out that this is a guide and anyone who copies it does so at their own risk and I am damned if I am going to have anyone sue me because they can't do this, or tried to drill tempered glass

 

[SkiFletch]

Great guide, I never knew you could do it with a cordless drill

 

[Eversurf]

What's the water for?

 

[superman]

Wow, you drilled that tank VERY close to the edge of the glass. I've never drilled a tank that close to the edge and have read to stay at least 2 inches from the edge of the glass unless it is near the top of the tank. I've only seen bottom tempered glass drilled that close to the edge. I hope it works out for you.

 

[bobf]

What's the water for?

To keep the drill tip cooler, I'd imagine?

That and/or to move the cack away as you drill through..

 

[andywg]

Wow, you drilled that tank VERY close to the edge of the glass. I've never drilled a tank that close to the edge and have read to stay at least 2 inches from the edge of the glass unless it is near the top of the tank. I've only seen bottom tempered glass drilled that close to the edge. I hope it works out for you.

No problems yet, I think this puts me into double figures for number of holes drilled now. One of my return holes on a marine pred seup is drilled about 1/4" from the silicone. Though that is higher up the side rather than the bottom.

What's the water for?

To keep the drill tip cooler, I'd imagine?

That and/or to move the cack away as you drill through..

I do it for both those reasons, though some say that cooling the tip is not necessary so long as you are not pushing too hard.

 

[superman]

The edges of the tank are pressure points. The glass wants to bow near the center of the glass and pull away from the edges where it is siliconed. That is what makes it so dangerous to go so close to the edge of the glass near the corners. Just words of warning, I am nearing my 100th hole drilled (paid professional) and have seen how easily a crack can travel from the hole drilled to the edge of the glass. Happy Drilling