Acrylic overflow box glued to glass surface


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Dec 2, 2020
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Hi guys,
let me introduce my overflow box :(
It's not sealed properly, has gaps on the bottom and also has a kind of "ventilation" holes near the bottom. Because of this level in my overflow box = level in the tank itself. I even can't use Herbie, otherwise my sump will be full immediately. 1 inch of water level = at least 2 gallons of water, or even more.
The problem is: it's impossible hard to set Durso, Stockman etc up. I tried so called "reverse Durso" silencer, it doesn't help me a lot, however sounds became more quiet. The noise is tremendously loud, despite I sleep in another room.

So the idea is: order new acrylic parts ~3/8 thickness, and glue them together, then to glass walls and the bottom. It's easier to lasercut all necessary weirs and holes for outlets, and it will look not too miserable in comparison with glass overflow box with glued stock weir on the top. Also I couldn't find the proper "black" glass, the only approach I could use is gray-ish, a bit transparent, looks weird.
My sump normally takes only ~4g of additional water, it means in case of inlet level is lower than 2 inches below water surface and if overflow box is leaked somehow, there will be a lot of water on the floor.

Thus the question is: how reliable is gluing acrylic parts with silicone glue (like Chemlux) to glass surfaces? I see some videos with acrylic baffles in sumps, but it's not a case, even if those baffles were broken, nothing would happened.

Thank you .

IMG_20210421_131304 (1).jpg
Top Shelf Aquatics


Stay Positive, Stay Productive
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Mar 22, 2012
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Sayreville, NJ
Yep, that overflow is for durso stand pipes. To get right to your question on gluing a new acrylic box to glass, your best bet is to us silicone made for plastic, and the best part is it's available at HD. You will want to go to where they sell acrylic sheet and you'll find a silicone caulk that looks like this:
Silicone Plastic.jpg

I've built multiple sumps using this silicone with great success. Just let it cure for ideally, at least a week, if not longer.

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