Okay, ever wondered about whether or not to drill your glass tank? How tricky is it, and what to do etc.? Well, in the process of a recent tank build I decided that I would bite the bullet and do it. After all, the worst that could happen was that I'd crack a second hand tank which cost me very little, and if it went well, then I'd learnt a valuable skill. I made the wife take pictures all the way through so I could give a blow by blow walkthrough of how it's done. I'm not getting into discussions about where the hole should be drilled or what size it needs to be, as this is a (hopefully) detailed guide to drilling a tank rather than part of a project. What you'll need to do this is: 1. A glass tank (obviously). 2. A need to drill it (see above). 3. A diamond tipped glass drill. 4. A good quality, well balanced cordless drill (no hammer action) with full charge. 5. The guide plate which comes with the drill (if you buy it from where I did). 6. A water spray bottle. 7. Paper towel roll or kitchen roll. 8. Cup of coffee (optional). Ok, first off, where do you buy a glass hole cutter? Answer: - here. Edit: I recently found another supplier who does the drills a lot cheaper. Anchor Tools. Again, this is a UK site. I researched all over the web, and asked in local hardware stores etc. (just got a lot of blank looks though), and 365Drills came up as the only place with any sort of product and sales at a reasonable price that you could trust. They sell on Ebay, but I hate that stuff so I went straight to their site. Reasonable prices aswell, and the 55mm drill I bought was delivered to my door next day for less than £30. This drill will be good for about 6 holes if used carefully, so about £5 per hole. I appreciate that this is a mostly American forum, so I don't really know where you can buy over there or how much it'll cost, as I'm based in the UK. But for a guide, I thought £30 for the drill delivered was well cheap. This is what it looks like, and you also get the guide plate aswell. And here's the process from start to finish. Use the drill on low speed, slow and steady, and no hammer action. Gentle pressure and let the diamond cutter do the work rather than trying to force it through as fast as possible. The drilling procedure will take 5 - 10 minutes, depending on the thickness of the glass What we need. Siting the guide plate. A good squirt of clean water for cooling and lubricating. Starting to drill. Hold the guide plate in position. When you get a decent start into the glass, remove the guide plate and spray again with water. Continue drilling slowly without the guide plate. Continue drilling, and spray with water occasionally. If you have a steady hand, spray while drilling (or get someone else to spray for you). Nearly through. When you're nearly through, support the underside of the glass plug to stop it falling through and cracking the other side of the tank. Paper towelling is ideal (plenty of it). It also stops the water from running straight through the hole and losing the cooling and lubricating process. There we are. Lovely job. Remember, the inside of the hole will have sharp edges where the drilling process finishes. Don't rub your finger round the hole to see what a good job you made of it. Things will go red, and your finger will hurt. A good way to look at this is to think that you're not drilling a hole as such, more grinding away the glass to form a hole. Speed is not necessary but a steady hand certainly is, along with clean water to cool the diamond cutter and wash away the ground glass. And that's about it. Easy, isn't it?