External Overflow Design for AGA

[midna]

Why?

 

I got tired of cracking glass while drilling it.

I didn't want to have a huge overflow box (too much glass required around the edges of a bulkhead to make it not crack.

I didn't want to pay anyone to drill the glass.

 

The first step is the make a way for the water to get from the tank to the external overflow box. I used a dremel and cut a notch along the back of the tank. It looks like this now on the back of my tank.

 

-----\______________/-------

 

Go to ace hardware, home depot, lowes, where ever and have them cut pieces of glass to build the small frame for your overflow box. The gray is the tank so you won't need that wall. I think all the pieces I needed cost me less than $10.

 

 

Measure and cut a piece of acrylic to fit snugly in the frame. Drill any holes for bulkheads. Using a lot of silicone, glue in the acrylic. When I glued it in, all of the bottom glass had silicone sealing it. This prevents small leaks from forming, the leak would have to go through the length of silicone along the bottom frame.

 

 

Glue the glass frame to the back of the glass tank.

 

By doing it this way, the only acrylic to glass joints are along the bottom, and have some length to them. That way, the imperfections of the edge joints between acrylic and glass don't matter.

 

Weaknesses:

 

This works great for me because my piping is not pushing up on the acrylic. The weight of the plumbing pulls down on it helping hold the acrylic firmly against the bottom glass frame.

 

This still has a acrylic to glass silicone joint which are inherently weak. I just helped alleviate this risk a little by increasing the amount of silicone that must be breached in order to create a leak. However, this is still a risk.

 

I'm using this on my 20L successfully . No leaks. I also beaded the silicone along the edges of the acrylic to glass creating yet another leak barrier.

[wombat]

I don't understand. If you can cut a long notch with your dremel, why not cut a notch...in the shape of a circle?

[midna]

Because if you are that close to the top the tank will crack. Also, I wanted an external box to hide pipes.

[wombat]

Not the tank--I'm talking about a hole in the pane of glass where you chose to use acrylic instead.

[midna]

Same reason. I kept trying to drill too skinny a piece of glass. My overflow box space was limited.

[bitts]

so it looks sorta like this

 

[midna]

yes. but with an acrylic bottom piece

[bitts]

You used a dremel to cut the weir right. Just use it to cut the holes. Start with a small one, then keep going rounf till its big enough to fit the bulkhead. Acrylic to glass won't hold. Then big mess. Switching to abs would be a big step up, but really glass is the way to go.

[Codeman]

+1 to bitts, if you read the side of a silicone tube (GE anyway) it gives a very low bond rating for plastics & acrylic. I wouldn't trust it to be watertight long-term.

[bitts]

http://www.nano-reef.com/forums/index.php?showtopic=218584

 

 

Nano paul's silicone thread.

[wombat]

I think in his application it should be fine. The acrylic is resting on a glass shelf, so the pressure on the acrylic>glass seam is pushing the two tighter together.

[bitts]

the same as why when you do the abs pipe overflow. The chance of a leak is farilly low. It still makes me nirvious. Acrylic to glass will fail over time.

[C-Rad]

...The chance of a leak is farilly low. It still makes me nirvious.

 

Sireousily?

[bitts]

ive had standard tanks without being drilled leak, blow a seem, crack. anything your goining to do after the fact better be perfect or dont do it. worst ive seen is a 76 gal bowfront pop its bottom front on the other side of the wall behind it. yet i run vortechs mmmm...

 

any way yeah i just dont trust silicone the same way others do.