How to Drill a Tank -Yes You CAN Do it!

[50seven]

This is something everybody seems to be freaked out about... Drilling glass tanks! But it's really not that hard once you know what to do and you have the right tools. I shared this on another forum, so here it is:

Drilled the tank last night, and thought I'd share some of the basics with the community. Like anything else, it's easy if you know how. Just make sure the glass panel to be drilled is NOT tempered! You will destroy the panel if you try to drill through it! There is a way to tell if the panel is tempered, as not all tempered panels carry a etching stamp. I'm too lazy right now to look up how you can tell- Google is your friend there.

Here is the tank sitting at my in-laws, yes it's filthy, but we'll soon change that. The previous silicone job left much to be desired, so I started by scraping off all of the excess and cleaning the glass with silicone remover, then washing everything with vinegar.

I'm doing my overflow in the middle of the tank; 1 1/2" bulkhead for the drain and 3/4" for the return line. Once I've marked the hole with a black sharpie, then I use a glass/tile drill bit first to drill out the pilot hole. The diamond hole saws usually come with a standard percussion concrete bit, which is useless for drilling into glass. It's important to use the same size as the pilot of the hole saw you are going to use. This is what works best:

For the actual hole, use a diamond hole saw like this:

I keep the hole wet with some kind of oil; this time I used WD-40. It keeps the cutter head cool, keeps the glass shavings from flying around, and aids in the cutting making it faster and cleaner.

I do the same with the diamond hole saw. The pilot of the hole saw should fit right into the hole I made with the tile drill bit. I keep the drill RPM's low and the cutting surface well oiled.

To reduce mushrooming, once the hole is started, I drill part way from the opposite side as well, then move back to the original side and finish the cut, always keeping it oiled...

(continued in next post)

 

[50seven]

...and voila!

Then comes the clean up. I love clean up- it's really not much work, and you get to think of the awesomeness of the job you've just done while you're working... Just wipe with some kind of cleaner that can cut grease, to get rid of the oil film. Windex works fine.

...and ta da!

Here you might also be able to see why I drilled in part way from the opposite side; I forgot on the larger hole on the right, and if look carefully you can see that the cut isn't quite as clean as the last one.

Now the bulkheads are installed and the tank is resting dutifully in my workshop to await the stand to be ready.

 

[dogstar74]

Nice write up, Thanks!

Aaron

 

[der_wille_zur_macht]

A few thoughts.

1) Turn the tank wo the side you are drilling is horizontal. This will keep your coolant from running away.

2) Use water for a coolant. Works great and nowhere near as messy or contaminant-laden as WD-40.

3) Put a circle of plumber's putty around the hole to make a dam, containing the coolant. Then you don't have to keep adding it.

4) masking tape or duct tape across the back of the hole. Keeps the puck from falling and potentiall damaging another side of the tank.

I don't understand why you made a pilot hole. None of the glass cutting diamond hole saws I have used had pilot bits, so no pilot hole required.

 

[50seven]

A few thoughts.

1) Turn the tank wo the side you are drilling is horizontal. This will keep your coolant from running away.

2) Use water for a coolant. Works great and nowhere near as messy or contaminant-laden as WD-40.

3) Put a circle of plumber's putty around the hole to make a dam, containing the coolant. Then you don't have to keep adding it.

4) masking tape or duct tape across the back of the hole. Keeps the puck from falling and potentiall damaging another side of the tank.

I don't understand why you made a pilot hole. None of the glass cutting diamond hole saws I have used had pilot bits, so no pilot hole required.

I appreciate your input...

...if I could just share my own personal experience and perspective...

1. Very good idea if possible for work environment, etc. Just make sure you are able to drill from both sides in order to get a clean hole.

2. I disagree. Having used both water and oil, I must say that the oil works way better. if cleaned properly, contamination is not an issue. the tank will usually be cycled anyway. If drilling an existing running tank, then you have no option but to use water.

3. Might work, but the oil needs to stay on the cutter head and keep it wet. It's not merely a coolant, it's also a lubricant to assist in the cutting process. If you've ever used oil on a drill press to drill through steel, you'll know what I'm talking about.

4. I personally like to drill part way through both sides of the hole to get a clean edge. This would not be possible if masking tape was put there. But protecting the other side of the tank from a falling glass plug is a very good idea, though mine always stay inside the hole saw.

5. Interesting. How were you able to keep the hole saw centered until the hole was to a substantial depth to not wander around? I've never tried doing it that way...

 

[Curious George]

Good post---It's nice to see pics and a step by step showing how it's done. It can be an intimidating task your first time round.

 

[Nathan.Titulaer]

I just took mine 40b out side and put my drill to the lowest torque setting and let the hose run water across it as I drilled. To start I tilted the bit slightly sideways and brought it to a 90 degree angle as it drilled. It was my first time and I drilled 5 holes and I am happy with all of them.

 

[Lyfsux]

Drilling through 1" glass any different then like say a 90g tanks glass?

 

[der_wille_zur_macht]

I appreciate your input...

...if I could just share my own personal experience and perspective...

1. Very good idea if possible for work environment, etc. Just make sure you are able to drill from both sides in order to get a clean hole.

2. I disagree. Having used both water and oil, I must say that the oil works way better. if cleaned properly, contamination is not an issue. the tank will usually be cycled anyway. If drilling an existing running tank, then you have no option but to use water.

3. Might work, but the oil needs to stay on the cutter head and keep it wet. It's not merely a coolant, it's also a lubricant to assist in the cutting process. If you've ever used oil on a drill press to drill through steel, you'll know what I'm talking about.

4. I personally like to drill part way through both sides of the hole to get a clean edge. This would not be possible if masking tape was put there. But protecting the other side of the tank from a falling glass plug is a very good idea, though mine always stay inside the hole saw.

5. Interesting. How were you able to keep the hole saw centered until the hole was to a substantial depth to not wander around? I've never tried doing it that way...

Water vs oil- what are your criteria for "way better?" The plumbers putty allows a constant deep pool of water in contact with the bit at all times.

Regarding the tape- put it on after you partial-drill the back side.

Centering the saw- steady hands. I have never seen or heard of someone using a pilot hole, but I can see the potential advantage if the problem is there in a certain application.

Drilling through 1" glass any different then like say a 90g tanks glass?

If anything, thick glass is easier. It just takes longer. But it is inherently stronger. Drilling thin glass is tough, since it is easier to break it with an errant dril, too much pressure, and so on. The real trick to this is to keep things cool, go slow (but don't stop the bit in contact with the glass), and provide plenty of cooling.

 

[schristi69]

I appreciate your input...

5. Interesting. How were you able to keep the hole saw centered until the hole was to a substantial depth to not wander around? I've never tried doing it that way...

You build a jig out of plywood, acrylic, etc. Drill hole in jig using hole saw. Clamp jig to glass. Hole in jig keeps the glass bit from wandering.

 

[Lyfsux]

If anything, thick glass is easier. It just takes longer. But it is inherently stronger. Drilling thin glass is tough, since it is easier to break it with an errant dril, too much pressure, and so on. The real trick to this is to keep things cool, go slow (but don't stop the bit in contact with the glass), and provide plenty of cooling.

ok, cause I am looking at buying a 300DD tank, and I'll need to drill a few holes in the back, but because the tank costs over $1,000 I am nervous.

 

[50seven]

Water vs oil- what are your criteria for "way better?" The plumbers putty allows a constant deep pool of water in contact with the bit at all times.

Regarding the tape- put it on after you partial-drill the back side.

Centering the saw- steady hands. I have never seen or heard of someone using a pilot hole, but I can see the potential advantage if the problem is there in a certain application.

I just personally found the cut to be smoother and there to be less wear on my drill bits. That's all I'm saying. I think the plumber's putty idea would really only work if the drilling surface was horizontal, but would definately help to confine the mess. Though I do like the Nathan.Titulaer's idea with the garden hose...

I imagined something like what schristi69 said about a jig. I guess I don't trust my hands to be that steady to do it without a guide of some kind!

Also without a pilot it would be difficult to drill from both sides to make the smoother cut.

If anything, thick glass is easier. It just takes longer. But it is inherently stronger. Drilling thin glass is tough, since it is easier to break it with an errant dril, too much pressure, and so on. The real trick to this is to keep things cool, go slow (but don't stop the bit in contact with the glass), and provide plenty of cooling.

+1. drilling my 1/2" thick 90G was easier than some of the smaller tanks I've done. Just go slow, keep it cool.

 

[schristi69]

Search for Glass Holes on youtube. They have several how-to videos

 

[atkinsg]

I drilled the side of a 20g for a fuge and used the plumbers putty dam with water method. Worked great. Trick is being patient, take your time, and don't push the drill to hard.

 

[jr_casteel1999]

nice post! im going to be drilling some holes on my 45 gal cube and i was thinking about trying this myself. i get the shakes just thinking about cracking the tank.

 

[Daemonfly]

Where did you find diamond hole saws with pilot bits? I've yet to ever come across any.

 

[widmer]

It's always nice to have a post to boost hole cutting morale :thumbsup:

This is seriously so incredibly easy in the sense that if you pay attention to a couple basic rules, you're basically guaranteed success. But I'm going to have to go with DWZM et al here on the proper method. Using oil in this application seems really unnecessary when water does an excellent job lubricating and has infinitely better heat sinking properties. Not to mention there is zero concern of yuck chemical residue. I personally have used the method DWZM describes, twice and with perfect flawless success.

Absolute KEY point:

Apply almost NO pressure on the glass while you are cutting the hole. Let it very gradually grind away at the glass. Stressing a rigid material via pressure is what leads to fracture. Likewise, be mindful of how steady and oriented your hand is; if you are careless and allow your hand to suddenly move so that the bit catches, this may cause a fracture.

Taking your time and allowing 10 minutes to pass as you slowly bore through the glass probably beats a few years of lamenting how you broke your tank trying to drill it (I wouldn't know :lol...

 

[AbZ]

thanks for posted this up .! ill try to drill my next tank .

 

[00Warpig00]

Gonna sound strange but if you have polarized sunglasses or have a polarization filter on an SLR camera you can clearly tell the difference between tempered and non tempered glass. Take your polarized lens and look around at some windows through the lens. Car windows are great for this. when you are looking at tempered glass you will see dark patterns in the glass that are visible through the lens that are there due to the way tempered glass is treated. non tempered glass will not have these dark patterns and will still appear 100% clear. It's a VERY visible difference. Just verify the lens you are looking through shows you the difference and you have clearly identified what I am referring to if you use this method. If every piece of glass you look at appears clear through your lens and shows no patterns don't trust it. You only get one chance to accidentally shatter a piece of tempered glass by drilling it. DRILL AT YOUR OWN RISK! I have never drilled a tank, this patterning is just something I have noticed while wearing my polarized sunglasses.


Nick

 

[50seven]

It's always nice to have a post to boost hole cutting morale :thumbsup:

This is seriously so incredibly easy in the sense that if you pay attention to a couple basic rules, you're basically guaranteed success. But I'm going to have to go with DWZM et al here on the proper method. Using oil in this application seems really unnecessary when water does an excellent job lubricating and has infinitely better heat sinking properties. Not to mention there is zero concern of yuck chemical residue. I personally have used the method DWZM describes, twice and with perfect flawless success.

Absolute KEY point:

Apply almost NO pressure on the glass while you are cutting the hole. Let it very gradually grind away at the glass. Stressing a rigid material via pressure is what leads to fracture. Likewise, be mindful of how steady and oriented your hand is; if you are careless and allow your hand to suddenly move so that the bit catches, this may cause a fracture.

Taking your time and allowing 10 minutes to pass as you slowly bore through the glass probably beats a few years of lamenting how you broke your tank trying to drill it (I wouldn't know :lol...

DWZM is a very knowledgeable and respected member here, and I value his opinion. Maybe I'll try water again next time, and see if I can really find a difference in the wear of the diamond cutting edge and the smoothness of the cut.

I used water in the past, but switched to oil when my father-in-law who is a tool & die maker suggested it, and I was impressed by the feel of the hole saw as I was cutting. It seemed to go smoother and cut cleaner, and the dust that came out of the hole was a paste that stuck together and was really easy to clean up.

Just sharing my personal experience, hoping to take some of the fear out of the whole drilling idea. For those of you trying to drill for the first time, just remember that patience is the key. Whether you use water or choose to use oil, keep pressure to a minimum and let the diamonds do their work.