Step-by-Step: Drilling Holes in Your Glass Tank for Bulkheads

[JustOneMoreTank]

Well I figured that I would show people how I drilled a couple holes in my glass tanks. First I would like to say that I am not an expert nor any more qualified than any other "do it yourselfer", however I have done this several times and never had any problems getting a near perfect hole in a glass tank.
#1 Use common sense and keep safety at the top of the list. Always wear eye protection and work slowly trying to think ahead. Be very careful with plugged in power tools around saltwater.
#2 Do not try and drill Tempered Glass! It will shatter for sure. Tempered Glass usually has a warning sticker indicating it as such and is usually the bottom pane of glass in a glass tank.
#3 Try to have the tank empty if possible.
#4 The correct tools make the job so much easier. I have drilled tanks with Dremel tools and tiny diamond bits. What a pain and it took forever. The hole I had was less than impressive... however it was functional and ended up fine. I would recommend a diamond coated hole saw. Google search and you can find them. They are pretty pricey however. A seller on Ebay called Richon_Tools sells them pretty cheap. However they ship from Hong Kong and sometimes it seems like he takes his time. He has a very good rating.
#5 Keep the bit and glass cool. I use a little dam around the hole I am cutting that is the top of a plastic cup. I have it duct taped to the glass and this keeps the water about half an inch deep. Others suggest using Antifreeze automobile coolant however I never have used it. Water works just fine for me. Also is easy and not deadly so I dont worry about cleaning it up perfectly.
#6 Move slowly and never force the drill bit into the glass. Pressing the bit into the glass may result in "chatter" or the bit to bite and end up cracking the glass.
#7 I use a very high speed setting with the drill (not sure of the RPMs) with a feather-light touch on the glass tank.
#8 Start the hole in the tank with the diamond bit angled somewhat from 90 degrees to the tank. If you try to start drilling with the entire face of the bit on the glass it will want to slide around and result in an ugly scratchy mess before it starts making the hole.
#9 Once the hole is started you will have a "curved slice" that is maybe 1/4 of the circle that you are cutting. Once this is started some you can remove the bit and begin cutting again at 90 degrees to the tank wall and shouldn't have the skipping/sliding around problem.
#10 Don't forget to have a towel or something on the other side to catch the perfect round glass disc and water once you cut through!

I hope that I didn't forget anything. I will post a few pictures that I took the other day. Hope this helps somebody!

[JustOneMoreTank]

Ahhh... forgot this little list:
Diamond Hole Saw size 60mm = 1.5 inch Bulkhead
Diamond Hole Saw size 45mm = 1.0 inch Bulkhead
Diamond Hole Saw size 38mm = 0.75 inch Bulkhead

Those listed are for standard sized bulkheads. There are some fancy heavy duty bulkheads that require a larger-sized hole in the glass tank. I am not sure the size Diamond Hole Saw required for those.
Use this conversion to determine what size you need. 25.4mm=1inch
MarineDepot lists a size 1 3/4 " hole for a size 1" Bulkhead. High School math will get you 1.75 x 25.4 = 44.45 That is the size in mm diamond hole saw that you need.
I hope that was easy to follow???

[JustOneMoreTank]

This is trying the difficult way with a Dremel and very small diamond bits (like your dentist uses)...

Cut the top off of a plastic tumbler-type cup with the Dremel.


Getting the supplies ready to go through the back of this 125g tank. (the back of the tank is painted navy blue)


The plastic ring is duct taped to the tank resulting in a very good (not perfect) watertight seal. This will do a fine job holding the water keeping the tank and bit cool.


Almost all the way through the glass. This is the slow way and results in a hole that is not perfectly circular. Did I mention that it is painfully slow and hurts your ears yet? I will not ever drill glass with my Dremel now that I have found the better Diamond Hole Saw bits for my cordless drill.

[JustOneMoreTank]

Now for some pictures of me drilling my 50g sump. I installed a 1.5 inch bulkhead requiring the use of a 60mm hole.


Some supplies


Duct tape the plastic ring on


Here you can see the large Diamond Hole Saw bit in the cheap cordless drill.


The hole is complete and it only took about 4 minutes I would guess.


Test fit the Bulkhead ... fits very well and seats easily


Rubber gasket goes on the inside (also know as the "wet side"). I use plenty of silicone as well. Some people don't but I dont ever worry about leaks doing it this way.
Be careful not to overtighten the bulkhead or any threaded PVC. You can crack/split the standard bulkheads this way. It just needs to be "good and tight" not "Super Human with a Wrench Tight"
Good. I hope this has been helpful.

[kbmdale]

very good thread.... I was going to start drilling this weekend, but now I gotta go get me a hole saw....Geez, I wish I had not seen how easy that was....lol

[Purple Haze]

where are the circular bit from?

[JustOneMoreTank]

It can be done with the Dremel for sure. I have heard of others using a "tile cutting bit" I think it is #562. Also I have heard of people using diamond coated Dremel bits that are listed as #7122, #7123.
However it is just too easy and the results are great with a real diamond hole saw like the ones I got off of Ebay.

[JustOneMoreTank]

Purple Haze... try this search. http://search.ebay.com/diamond-hole-...trypageZsearch

[BeanAnimal]

plumbers putty works much better for creating a dam around the hole. No tape, no leaks.

Also using metal duct tape on the backside of the hole will help prevent chipping when the hole is almost finished (better yet a wooden black camped against the glass).


Bean

[JustOneMoreTank]

Hey Bean... Thanks for the info. The plumbers putty would work better I agree. However I did not have any laying around and the duct tape works great if you take your time and press it down well all around. When cutting the hole in the pictures (50g sump) I actually was more concerned with the photo taking that I did have a little bit of a leak. No big deal. The last 4 holes that I have cut I did better with the duct tape and did not have any leaking cooling water at all.

[sscherin]

I just ordered a 6 piece core drill set off Ebay.
32,35,38,42,45 and 50mm bits

I got 42mm and 45mm bits so I can do 3/4 and 1" bulkheads
I don't know what I'll do with the others.
Maybe drill holes in rocks when I have nothing better to do.

$20 for the set

[JustOneMoreTank]

About $3.50 each is a great deal and only $20.00 for the set. Check out the prices for a similar sized set here:
http://www.diamond-drill-bit-and-too...Drill/MAIN.htm
Try $291.00 !!!!
On the above posted link there is lots of useful information about using these diamond coated hole saws to cut glass aquariums as well as maintaining the bits and cutting other materials. This link should be a mandatory read for anyone cutting glass tanks.

[H20ENG]

Glad you did not use antifreeze.
Many people have misconceptions that antifreeze causes the water to be more heat conductive, or will magically cool itself. Pure water is the best coolant and heat transfer fluid- which is why every other materials specific heat is compared to that of water- which is 1.0.
Antifreeze is used for just that purpose- to lower the freezing temperature of the water (mix). It actually hampers its heat carrying capacity a bit, but that is the tradeoff for being able to not freeze up in cold weather.

[Purple Haze]

Thanks for the links.

[JustOneMoreTank]

Purple Haze... no problem.

H20Eng... I saw where someone had suggested antifreeze and I wasnt going to argue that point. I didnt think that AF would make water a better "heat sink". Ohh also AF is really bad if it ended up in your tank.

[shanebc21]

bump

[JustOneMoreTank]

Since the post just got a bump I figured that I would add some recent pictures that I took the other day...

This is a photo of the back of my 120 RR tank with a recently cut hole for a 1" Bulkhead.


Here is a series of shots of cutting a second hole to allow placement of another 1" Bulkhead...

Duct tape is on the inside of the tank so that the glass hole piece does not drop into the tank...


that is the diamond coated drill bit...


and the last two photos were difficult to take but they show a side view through the glass that is being cut. You can see the hole being carved out of the glass through the side edge. It was difficult for the camera to focus correctly.

[JustOneMoreTank]

Here are a few pictures of the tank as it is right now... sitting on its front viewing pane of glass in the living room. I have siliconed in all 8 Bulkheads (four on the back wall and four in the bottom). Two 1.5" and two 1" bulkheads are part of the Closed Loop and are all on the back glass wall. The other four bulkheads are the standard 1" and 3/4" AGA overflow sized holes.

[shanebc21]

Here’s my progress following most of your steps. I drilled one 45mm hole (already cut out in pic) and one 38mm hole (the one with the cardboard stencil). Your advise was helpfull. Thanks for starting this thread.

[shanebc21]

I bought my bits from this guy http://search.ebay.com/_W0QQsassZlauQ2aQ2aQ2a . He can send you any size, just ask him. Great prices, got it in 5 days. As you can see they got the job done. (this info is for other reefers who read this thread)

[fishtk75]

JustOneMoreTank
The holes that you put in the tank for close loop.
what is it for a wave movement action or?
And the overflow boxes is is for what?
Just looking at everyones ideas.

[JustOneMoreTank]

Originally posted by fishtk75
JustOneMoreTank
The holes that you put in the tank for close loop.
what is it for a wave movement action or?
And the overflow boxes is is for what?
Just looking at everyones ideas.

The holes I drilled in the back wall are all going to be used for my Closed Loop. I first drilled the two holes for the pair of 1" Bulkheads. Reading here on RC I figured that the holes would not be large enough for the pump that I wanted to run. At first I was going to use something like a Quiet One pump for the Closed Loop. Later I decided that a Sequence Dart would be a much better choice. Now I needed larger holes for the intake of the Dart pump. I then cut a pair of holes to allow placement of the 1.5" Bulkheads that will T together to provide water to the intake of the Dart pump. I will use the smaller holes that I drilled to return two of the four outputs from the Oceans Motions Super Squirt coming from the Closed Loop Dart pump.
As far as the overflow plumbing... I am planning on using both of the 1" drains to go to the sump. One will feed the skimmer and the other will empty into the sump. The 3/4" plumbing will be plumbed to act as an emergency overflow and return into the sump. These two smaller pipes will extend up higher than the waterlevel in the MegaFlow Overflows and only drain water in an emergency if the main 1" drains are not draining the tank properly.
I hope that helps clear things up some.

[steve68]

10 buck's for 1.5 is not a bad deal.
i use'd a dremell & it took for ever then my friend drilled a 1.5 slot by 12 inch long for an external overflow with a tile bit an a dewalt hand tool took about 10 minutes on 1/2 inch thick glass, ever since i have been drilling all kinds of holes & slots,a 1.5 inch hole on 1/2 inch thick glass takes 5 minutes or less. i did use a diamond hole bit one time from my friend & it took less then 2 minutes so for 10 bucks im going to buy one.

[DerekW]

Originally posted by shanebc21
I bought my bits from this guy http://search.ebay.com/_W0QQsassZlauQ2aQ2aQ2a . He can send you any size, just ask him. Great prices, got it in 5 days. As you can see they got the job done. (this info is for other reefers who read this thread)

I imagine for his prices that these are not top qulity bits. How many holes have you gotten out of a bit and what thickness glass?
Having said that, if you get 4 or more holes out of each bit you are way ahead of the game, just about cheaper than a dremel bit anyway

[JustOneMoreTank]

Once you use the Diamond coated hole saw you will not ever go back to using the Dremel I promise.
I have purchased one Diamond Hole Saw from the Ebay seller lau. I only needed to cut one last hole for my 1.5" Bulkhead. I think that it could easily cut 2 more holes. I had purchased a set of Diamond Hole Saws from a different seller off Ebay name was something like Richon_Tools. The bits are of the same quality. Both are out of Hong Kong. Both are way cheaper than anything you can find in the US. The bits that I have seen for the same purpose cost $50 to $90 each!!! Perhaps the expensive bits will last longer but not long enough to justify the massive jump in price.
I am not sure how many holes the expensive ones can cut but that is way too much money for bits when the Hong Kong units cut great and give you 3 to 4 holes. The glass I have been cutting varies from thick (120g AGA tank) to medium in thickness (50g AGA tank).