"Tile drill" covers a lot of ground as there are many types of tile and many types of drills that are used to drill tile ...... some with poor or middling results, some with good results. Too, using a piece of masking take on the substrate serves absolutely no purpose other than to hinder loss of heat from the substrate and increase the probability of breakage from thermal shock. The reason I'm sure of myself is because for 30 years I owned and operated a glazing contracting corporation, and one of the things we did every day was hole fabrication in all manner of hard and vitrified materials like glass, porcelain, granite, cement, stainless steel, ferrous and non-ferrous metals ..... "Go slowly" is also vague. The speed with which a hole is drilled in vitrified materials depends on the thickness of the material, hardness of the material, quality of the tool being used, the coolant/lubricant, and the amount of pressure used, which should always be minimal. It's good to remember that you are using a tool to grind through glass, not drilling it as you would drill through metal or wood. Pressing too hard increases the potential for breakage and large areas of spale (chips/flakes) on the opposite side from which the work is done, and it shortens the tool life. The interface between the tool and the substrate must have a steady flow of coolant for best results. Of all available bit types capable of making holes in vitrified materials, the common and least expensive masonry drill, seen below, is least suited to the job and a poor choice. At best, these ^^^ are only suited to drilling low-fired clay (terra cotta). If you are forced use this type of bit for clay, try to limit your hole size to no more than 5/16". Coolant isn't absolutely required when using this bit for drilling low-fired clays, but it does extend tool life. Al

Hi all, I'm new here, This thread caught my eye because I work with glass for a living. If the glass is not tagged there is no way to know if it is tempered but it is a safe bet to assume any aquarium twenty gallons and up, that is made of glass 1/4 inch or less is tempered. This statement; > Can apply to any glass that becomes scratched, tempered or not. TG will more likly break and should break into small, safer pieces then untempered when trying to cut through it. Tempered is not stronger then untempered glass, it's just more impact resistant and when it breaks it should fall into small cube-ish pieces rather than sharp shards If the tempered glass is thinner than 1/4 the safest way to cut into it is to sandblast it which not many places that blast know how to work with glass but there are alot of hobbiest and small independant glass etchers around that might be able to it. It still might break though, you just have no way of knowing. With diamond wheels the main thing is to keep enough water flowing over the work piece to keep the glass from over heating which will expand the glass unevenly and crack it. Many diamond cutters are fine without water, you'll just ruin the glass without it or at best, clog the cutter so it won't cut anymore (which also causes more heat). Hope that helps, It's nice not being a lurker for once Danny

I was reminded about the drill's tendency to blow through when I had to drill a hole through my block foundation - the block was fine, the stucco covering was decidedly not, lol. When drilling a hole in a piece of wood, you need to place a piece of sacrificial wood on the backside in order to get a clean hole without any splintering (there are ways and drill types that prevent this, of course) - I would think that using something like a brick on the backside would go a long way towards preventing any excess damage. Totally preventing it would be a long-shot, but it could help. Masonry twist drills are not meant for any precision / delicate work, which is the root of the problem in this case. Yea, I had totally glossed over that part of the OP's post. I saw where Sandy had suggested the multimeter and kinda ran with it (as I'm wont to do sometimes). Though now that I think about it, how is the pot going to be used? Is it going to be standing straight up and have the water cascade down the sides, or will it be laying down on its side and look like it's pouring water? The answer to this will go a long way in figuring out the best type of hole to drill - cause you'll have to think about how to plug the hole afterwards so that it will hold water (or at least prevent a huge leak). Drilling a small hole large enough for just the cord could be sealed up with some silicone caulk, while having a hole large enough for the plug as well would need something like a rubber plug or something else to fill the opening. Yet another aspect to consider. - Mike

"Glue, solves everything I guess lol. Sort of like duct tape :D" Not everything, but it works well when applied correctly. Trying to fasten to a tile wall to cover a hole is not a good place to be installing anchors into the tile. They might hold, but if there has already been any damage to the tile or backer just drilling a hole (even with the correct carbide tile spear point bits) can make matters worse. The tile could also pop off the backing when the screw expands the anchor making the needed repair even larger. This is a perfect place for a gap filling product like silicone seal glue. The cover can be made large enough to have an acceptable bonding area, and the silicone will stick to the smooth tile well enough to hold the cover in place once it sets. It will likely take some tape to hold the cover in place till the silicone sets up. A better repair can then be done at a latter convenient date if desired by cutting the silicone and removing the cover and any silicone remaining on the tile.