Question on building an overflow box in tank

[runway1]

The lfs said don't try and build your own overflow in a glass tank because it's too tricky. They said you can't use acrylic for it, that it will not stick and soon fail. They said you need to glue the acrylic to a layer of glass on the inside and glue up to the tank. Does this sound right? Are glass tanks with overflows made with a acrylic/glass laminate like this? TIA.

 

[gooyferret]

You can use acrylic for an overflow box inside the aquarium....I would suggest making the box first with silicone as a sealant and to bond it together or use an acrylic glue that is made to be used on acrylic that actually bonds the acrylic together. After you get the box made i would then silicone it in the spot where your going to be placing it and let it dry.

 

[mykpoz]

sounds like it would be so much easier to do a HOB overflow ;(

 

[runway1]

That's what I currently have, mykpoz. I'm updating my 55 to a 120 and trying to to have a cleaner backside to get closer to the wall - although with my closed loop pump system, I may not be able to anyhow, I'm just tired of dealing with the HOB.

Gooyferret, question was can I glue the acrylic to the glass with issue? If it fails at 2:00AM, my tank destroys my house.

 

[mykpoz]

I'm updating my 55 to a 120 and trying to to have a cleaner backside to get closer to the wall - although with my closed loop pump system, I may not be able to anyhow, I'm just tired of dealing with the HOB.

well my answer would have been a bit different if you mentioned the difference in tank sizes. I was speaking on behalf of your current setup, and the issues you might/would run into.

As long as you properly build/seal/cure your overflow you should be good...
But if your like me, I wasnt willing to gamble on that, so I had the LFS custom order me a tank with the holes/ overflow installed by tank company.

 

[seaham358]

Why not have the back of the tank drilled on both upper corners and use bulkhead fittings... No need for a box of any kind ... just some cheap plumping elbows and nipples and your done.... I have a plastic screen on the elbows so no fish or snails go down the overflow..

 

[Brenden]

I think your lfs was just saying that silicon does not bond to acrylic like it will bond to glass. (which is correct) If you have to use acrylic I would rough up the area you are bonding with a coarse sand paper . It will help. They make a glue just for acrylic that melts it together. Very strong.

 

[runway1]

How about the acrylic to glass bond? That's the question all. Bonding the acrylic box to the glass walls. Does this work?

 

[seaham358]

why would you want to bond a box to the wall?? what exactly are you lookign to build? Any overflow box that I have seen hangs on the tank, one side in the water the other out.. I'm missing something here I guess...