ChadO
Active member
Greetings,
I thought I would share my experiences from this past weekend when I drilled my 75g AGA tank for the Bean Animal overflow system.
Equipment Used
I thought I would share my experiences from this past weekend when I drilled my 75g AGA tank for the Bean Animal overflow system.
Equipment Used
- 75 gallon AGA tank, 48x18x21, ¼” thick glass, laid down on the floor of the garage, resting on its side on 2x4’s.
- DeWalt 3/8” Pistol Grip Variable Speed Drill
- 42mm and 48mm glass hole saw bits from Bulk Reef Supply
- Wolfcraft Drill Guide – as seen in the Bulk Reef Supply video on how to drill a glass aquarium
- Plumber’s putty
- Water
- Shims
- Nerves (of the frayed form)
- I started off by assembling the Wolfcraft Drill guide (minus the springs) and attaching the glass bit to the guide, and then the drill to the guide itself. I measured out and marked my locations for where I wanted my holes. I was going to be drilling 5 holes (2 for ¾” return lines, and 3 for 1” drain lines). I chose to come 3.5 inches down from the top of the trim piece. I then spaced out the holes across the back where I wanted them. It ends up with the two return holes on each end, and the three drain holes near the middle back.
- Once I had my “x’s” marked, I took the bulkhead, centered it on the x, and then traced around the bulkhead so that I had a circle that was larger diameter than the hole I was going to drill. I used this marked circle as a guide to build the dam with plumber’s putty.
- Next, I set the drill guide over the “x”, but since it covers it up with the bit installed, I looked from the underside of the tank to gauge if my bit was centered over the “x”. This worked pretty well.
- Finally, once I had my hole saw bit centered over the “x”, I filled the area with water, and then started drilling.
- I ended up with 5 nicely drilled holes. The first one was my worst one, and probably to be expected. It has an ever so slight angle to it, but with the bulkhead installed, it is totally fine. I’m probably being overly critical as well as you can’t see it, but rather have to feel it and then look really hard to even notice. The gasket more than covers it.
- My first return hole that I drilled took me 1 hour and 7 minutes. It was also the first time that I had ever drilled glass before in my life. The 2[SUP]nd[/SUP] return hole took me about 45 minutes. Last night, I drilled the three remaining drain holes. The first one there took 6 minutes – yes, only six. The next two, I was back to about 45 minute average. I think the first drain hole was so much faster because the bit was brand new.
- There is a lot of information out there that says to not use any pressure, just use the weight of the drill. That is what I did for the first hole, and that is why it took me an hour and seven minutes! Truth be told, I later found documentation that you can use medium pressure, or up to 14 lbs of pressure, and you want to shoot for around 250 RPM or so. On that first hole, I know I went way to slow on the RPMs, and didn’t intentionally use any pressure. This is what lead to the long drill time, I’m sure. So, once you have the hole started, and have made some progress, I found that applying some light pressure certainly helped. It is much more realistic than just using the weight of the drill.
- The drill guide was very helpful. I had no bit creep at all when starting my holes. That alone was probably the best part of using the drill guide. I saw folks drill without the guide, and they would hold the bit at an angle and drill on the glass to get a groove started and then stand it up and go from there. That looked to me to be a lot harder than it was worth. I was quite happy with the drill guide.
- Wear ear protection! I don’t know how, but for some reason it took me to part way through the 5[SUP]th[/SUP] and final hole to think to use my target shooting ear muffs to quiet the noise from the drilling. It was an amazing difference once I was wearing them, and I can’t believe I put up with the noise for so long. Just silly, really.
- Consider lifting the tank up to a better working height than just resting off the ground with 2x4’s. Bending over running the drill for long periods of time is really sore on the back. I took frequent breaks, but it was a very sore position after a while.
- The plumber’s putty dam and water worked really well. Even at higher rpm’s, the water stayed in the dam, and the bit and glass stayed really cool.
- Buying a practice piece of the same thickness as your tank would be a good idea if you have never done it before. In hindsight, I wish I would have done this and then I would have been able to experiment a lot. I learned that glass is really more durable than what I was fearing. I certainly don’t treat it lightly, but even as I got better, I am guessing I was playing it safer that what a person would need to do. I’m OK with that, I still have my tank in one piece.
- When the water suddenly rushes out of your dam, you’re almost through. That is one of the fun parts, actually. You’re going along, then all of the sudden, the water is gone, and you’re almost through. On a related note to that, measure the thickness of your glass, and then measure that distance up from the bottom of the drill bit. Either mark that, or visually remember it, and that will help you get an idea of how close to the end you are. I say this because when the drill bit is in a pool of murky gray water, it is hard to get an idea how far through you are
- Lots of patience. The process itself isn’t really that hard, nor scary once you drill through your first hole, but it does just take a while. I took breaks throughout so that everything stayed cool, and to give my back a rest. It’s just not a very fast process.
- I think the reason that my first 1” drain hole was so much faster was the bit was brand new, and I applied more pressure while drilling. I still kept it pretty light, but the combination made a big difference. I also think that once you have used those cheaper bits for a while, they really start to drop off on effectiveness. My guess is that the high end ones will last much longer. If I was going to be drilling multiple tanks or going in with multiple people to drill tanks, I would spend the extra money for the higher end bits. As it turned out, the BRS ones were fine for what I needed.
- If you had access to a drill press, and could work out lifting the tank to support it in some way, I think the drill press would be ideal over a hand drill. The trick is probably figuring out how to raise the tank to the height needed for a drill press, but if you could, I think you would have a lot more options on applying constant pressure and RPM speed
Last edited:
