Hmm... Did I make a mistake?... Overflow box...

[Charley Diesing]

Well I now have installed my new BeansAnimal Acrylic Overflow Box 3/16ths inch. And after reading some posts about acrylic I'm a little worried. About the thickness and also the fact that Glass and Acrylic don't bond very well.

This is on a 20 Long. With Bean Animals plumbing.

Let me know your thoughts. Will I run into problems? Am I a goner?

Thanks,

Charley

 

[mcgyvr]

all depends on how you built it.
got some pics maybe.
With proper bracing you could use 1/8"

 

[Charley Diesing]

all depends on how you built it.
got some pics maybe.
With proper bracing you could use 1/8"

Hmm there is no bracing.

I'll try to describe it as I have no way of uploading pics.

Its 18 inches long 3 inches out from the class. And 5.5 inches high. I used Weldon #4 to seal it together. No bracing. Should I put some sort of brace in it?

Maybe between the middle hole and the right hole. And the left hole and the middle hole?

Thanks,

Charley

 

[hebygb]

OK.. so... if I understand correctly, you have an acrylic overflow and intend to attach this to a glass tank. There is really only one way to do this. Build the overflow as a complete sealed box (4 sides and a bottom) then using a rubber gasket between the overflow and the glass wall. This gasket will behave like a washer around each hole/bulkhead that goes out the back of the overflow and through the side wall of the glass tank. The bulk heads will essentially hold the box against the tank wall and seal the washers/gasket between. As for the thickness of the material, I am afriad that you have chosen too thin of material, I would advise using 1/4" thick cell cast acrylic.

 

[Charley Diesing]

OK.. so... if I understand correctly, you have an acrylic overflow and intend to attach this to a glass tank. There is really only one way to do this. Build the overflow as a complete sealed box (4 sides and a bottom) then using a rubber gasket between the overflow and the glass wall. This gasket will behave like a washer around each hole/bulkhead that goes out the back of the overflow and through the side wall of the glass tank. The bulk heads will essentially hold the box against the tank wall and seal the washers/gasket between. As for the thickness of the material, I am afriad that you have chosen too thin of material, I would advise using 1/4" thick cell cast acrylic.

Yeah kind of like Glass-Holes overflow boxes. As for thickness of Acrylic the company I ordered from didn't make 1/4 inch in blue(the color of my tank)...

Well now that I have Siliconed everything in place. Is there away to get around this? Would installing some sort of brace help at all? I know people that just have acrylic overflows siliconed to there tank. It seems to work.

Thanks,

Charley

 

[uncleof6]

This is attached to the outside of the tank? Or the inside?

Inside the tank, don't worry about it.

Outside the tank, you may as well remove the box, because it is going to remove itself anyway. Additional bracing is not going to help. You cannot get a structural bond between glass and acrylic using silicone. There is no work around, except in the minds of folks just wanting to tell you what you want to hear.

You can use the "double gasket" (one under the flange, one between tank and box,) however this is a another potential leak point, and will keep you awake at night always wondering.

Outside the tank, do it right: use glass.

 

[Charley Diesing]

This is attached to the outside of the tank? Or the inside?

Inside the tank, don't worry about it.

Outside the tank, you may as well remove the box, because it is going to remove itself anyway. Additional bracing is not going to help. You cannot get a structural bond between glass and acrylic using silicone. There is no work around, except in the minds of folks just wanting to tell you what you want to hear.

You can use the "double gasket" (one under the flange, one between tank and box,) however this is a another potential leak point, and will keep you awake at night always wondering.

Outside the tank, do it right: use glass.

The box is inside the tank. You say don't worry about it. Does that mean it will work or not?

The box is not outside the tank.

Thanks,

Let me know.

 

[aus996]

I had visions of an acrylic box sitting outside the tank as well, immediately followed by visions of a flood :_0.
With a wier inside the tank as already mentioned, glass is best, complete acrylic box with double oring seals is more secure than just two piece acrylic (but has the increased risk associated with the double gasket) or as you can leave it as it is Remember its being supported by some of the water volume in the tank as well.

I think the primary concern with this set up is that if the wier isn't water tight, when you power down the return pump the water level will, overtime all level out - ie your tank will eventually drain until to a level that may be lower than the overflow lip. This may not be an issue if your sump can take the extra water. The leak could also be so small that it wont make much of an impact for the short period of time the pump is off so not worth worrying about. Remember it wont be a sturdy as a glass wier so dont treat it roughly or knock it about when rearranging your tank. If it does peel away (lets say a catastrohic failure) the tank will drain until the main siphon is broken, again if your sump can handle it, not a huge problem but keep in mind the tank water level will also be a lot lower in this scenario so if you have any corals etc close to the top now they could be exposed - not good).

I did one in glass and actually drained the tank to a level below that which I was working at to replace an old acrylic set up, didnt upset anyone in the tank and works a charm so thats still an option for you if you want to go glass, at least the holes are already drilled.

 

[nemosworld]

I don't understand the whole acrylic and glass bonding issue, my current professional built tank with pvc bottom and acrylic external overflow has no leaks and works as expected.

 

[aus996]

Cool, how is it bonded to the glass, just silicone?

 

[peppie]

I don't understand the whole acrylic and glass bonding issue, my current professional built tank with pvc bottom and acrylic external overflow has no leaks and works as expected.

Is that Black glass???

 

[nemosworld]

the overflow was attached with silicone and the back glass was painted black.

 

[uncleof6]

AGE is making hybrid aquariums, using PVC, Acrylic, and Glass. They are using proprietary adhesives for the Glass/PVC bond, and the Glass/Acrylic bonds. I am not aware of a main stream builder that is irresponsible enough to use silicone to bond an acrylic anything to the outside of the tank, if it is expected to hold water.

 

[reefermad619]

They best way I found to attach and acrylic overflow to a glass tank, internally, was to make a 5 sided box like someone else suggested and use RTV silicone to attach it. Similar to the double gasket set up other have mentioned. So cut 3 holes out the back of the box to match the holes for the drain. Apply a generous amount of silicone to the back of the box and especially around the holes. Make sure the holes all line up. Put enough silicone so when you clamp the box down to the back of the tank, silicone will squeeze out the drain holes. Let this dry. Then trim back silicone that is in the way if sliding the bulk head in. Then install bulkhead like normal.

 

[nemosworld]

AGE is making hybrid aquariums, using PVC, Acrylic, and Glass. They are using proprietary adhesives for the Glass/PVC bond, and the Glass/Acrylic bonds. I am not aware of a main stream builder that is irresponsible enough to use silicone to bond an acrylic anything to the outside of the tank, if it is expected to hold water.

Good point, my fault, I should have said adhesive like rtv 100 series. Just used to calling it silicone.

 

[Ron Reefman]

I've used a 3M Co adhesive called 5200. It's not cheap, it has a rather slow cure time, it needs to be under pressure (clamped) and it's white. Oh, and it cures underwater. It's a staple in the marine boat industry. I've used it to adhere a couple of acrylic overflow boxes inside glass tanks and 3+ years downstream I've had no issues. I'm not recommending it, I'm just saying I did it and so far it seems to have worked... but you'll have to live with white seams!

 

[barjam]

I don't understand the whole acrylic and glass bonding issue, my current professional built tank with pvc bottom and acrylic external overflow has no leaks and works as expected.

That can't be using normal tank silicon. My internal box is the same size as yours with normal silicon. Good enough for the inside but when I decided to move it down a bit all I had to was loosen a corner and pull. It came off very easily.

 

[C Dog]

I've used a 3M Co adhesive called 5200.

5200 is some tough tough stuff!

 

[freeswimmingfis]

OK, I am not debating the fact that you can not use silicone to attach acrylic to glass. BUT, I have always wondered about RR tanks, like mine.
I have an Oceanic 156g RR tank. It has 2 "Megaflow" overflow boxes that are (or at least seem to be) siliconed to the back wall and bottom of my tank. I have also had a few other RR tanks that had acrylic corner overflow boxes attached in the same way, with silicone.
I am just not sure how the RR tank manufacturers do it but we say not to?
In fact, way back in 1993, I drilled an Oceanic 110g and siliconed acrylic overflow boxes in the corners. I sold this tank to a coworker about 10 years ago. I just asked him about it. He still has it running with no issues at all.
Sorry for the hijack, I will open a new thread if I need to.
Thx

 

[uncleof6]

Not saying you cannot do it. It is a risk at best. Many RR tanks, use ABS for the overflow, that alters the physics a bit. In general, if there is no issue with potential leaks, or self destruction, concerning an acrylic/glass join, silicone is adequate. It is just a question of longevity, and the type/quality of the silicone used plays a role in that.

If the failure of such a join will flood your house, or otherwise cause death and destruction, don't do it. Silicone is inadequate for such a join.