Neptune Aquatics

Help cutting an overflow into glass tank

I'd like to cut an overflow into the side of a 75 gallon glass tank, like theses pictures I took from the net:
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IMG_4004.jpg

Then I would install an external overflow box. I have drilled holes for bulkheads in glass tanks before, so that is no problem, but this seems much more delicate. It seems people who do this use a diamond rotozip bit and a dremel tool. I have also read that all the edges should be rounded or stress points will be created and the panel will be likely to crack after holding water for a while. Thus one needs to make a wooden guide for the dremel tool. Have any of you done this sort of thing before? If you were successful, could you give me any advice and would you be willing to come help me do it in exchange for friendship and beer? Do you think I am better off just having a small internal overflow box with some round holes drilled to drain the water to an external box? Any opinions would be appreciated.

Thanks,
Gabe
 
I just found this computer drawing of what I want to do, just to make it clear. Note that my tank has black plastic trim, not glass eurobracing like the tank in this picture. But I could still leave part of the plastic trim intact so it would have some tensile strength to prevent the aquarium panes from separating.
Tank_overflow_A.gif
 
Lol, I haven't actually done anything yet Erin! Except spend tons of money ordering supplies...:( I'm still planning and moving into my new place. Have you ever cut into glass like this? This is one time that acrylic would be easier to work with...
 
Originally I had an HOB weir on my last tank. I hated it. It required a little pump to make sure it didn't clog with air bubbles and it took up too much room in my tank. Granted, my current tank is a lot bigger, so I am not as pressed for space, but I really want as little in the display as possible. Also, I want to set up a beananimal overflow, so I would need to heavily modify any HOB filter I could buy anyway. After drilling my last setup, I would never run another tank without drilling an overflow. I just want to take it a step further and put the overflow box on the outside of the tank. The only issue is cutting a slit in glass. I guess no one here has done that?
 
Based on what I read on other forums where people documented how they did it, I was planning on using this bit. I will use a dremel tool with one of those guards on it to keep it perpendicular to the glass and I will use a piece of wood to make sure the cuts are straight. I was planning on drilling two small holes in the glass with diamond hole saws at each end of the slit I want to cut. Then I will use the above bit to cut out both tangent lines that connect the circular holes. Thoughts?
 
Is this a framed tank like pic #2? That seems really risky.

An internal weir and external overflow seem to be a better solution. There are lots of examples of this on reef central. Look for BeanAnimal threads.
 
It is a framed tank like pic 2. I wasn't planning on entirely removing any section of the frame though; just cutting a section of the frame shorter so the overflow could be closer to the top. My backup plan was to drill holes with a hole saw and put an internal weir and external box. So you don't think it's worth trying the diamond dremel bit to connect hole saw holes?


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It is a framed tank like pic 2. I wasn't planning on entirely removing any section of the frame though; just cutting a section of the frame shorter so the overflow could be closer to the top. My backup plan was to drill holes with a hole saw and put an internal weir and external box. So you don't think it's worth trying the diamond dremel bit to connect hole saw holes?
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I personally would be worried about reducing the structure of the tank. Commercial tanks are built pretty close to the structural limit. Max profit, don't you know! Cutting anything out seems like a high risk activity.

Is this going to be on a long or short side?
 
I was originally planning to put it on the short side, but my girlfriend is pressuring me to rebuild the stand in order to make the system flatter against the wall for aesthetic and "room flow" reasons, in which case I would put it in the middle of the long side. Do you think that makes a difference?


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First off, you are going down the road to marriage letting the GF decide on 'room flow'. :D:D:D!

Since the long side is longer it will have more flex. Cutting in the middle of that is the weakest spot.

Adding a euro brace like the drawing in your second post would help.
 
Yeah, she and I have been dating for over 5 years and we're finally moving in together :)

Ok, then if I actually attempt this, I will do so on the short side. I considered adding eurobracing to the side I cut, but I figure that the external glass overflow that ill silicone on will act in the same way. Maybe I'll add a eurobrace anyway... Thanks for the input!


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