Acrylic overflow box on glass aquarium?

[incapearl]

I just siliconed my acrylic overflow to my glass aquarium. I used GE silicone 1. Is this going to work?http://rs1364.pbsrc.com/albums/r737/ian50moss/Reef%20Tank/image_zps4f19e941.jpg~320x480

[trickedout900]

in my experience it will work since it's on the inside. Acrylic does not bond to silicone well enough for external use.

[incapearl]

I guess that makes sense since there would be less weight being inside the tank and not having any plumbing pulling on it. Thanks, that makes me feel better :)

[ca1ore]

As was noted, silicone does not adhere well to acrylic, so at least be prepared for the box to fall off at some point (and plan sump size accordingly). I assume the acrylic box does not have a back and that you are edge gluing to the side of the glass tank? It may never fall off, jut be prepared if it does.

[incapearl]

As was noted, silicone does not adhere well to acrylic, so at least be prepared for the box to fall off at some point (and plan sump size accordingly). I assume the acrylic box does not have a back and that you are edge gluing to the side of the glass tank? It may never fall off, jut be prepared if it does.

Gotcha. Yes it's just on the edge. There's no back to the box.

[_ToXIc_]

was the back of the box scuffed up at all? i may prolong the day it comes loose...

[incapearl]

yah it was not a polished finish on the edges that I siliconed

[viggen]

I have zero experience using silicone on acrylic..... if it was me I would yank it and use glass

Do one of those coast to coast overflow boxes so you would only need two pieces of glass cut the length of the tank.

Otherwise like stated be sure your sump is setup for holding the proper amount of water for the day the acrylic overflow comes off. Might be a week or 20 years from now

[Denver_Keeper]

My experiments with using silicone to mate glass and acrylic was a total failure. It does not take much force to cause breakaway on the acrylic surface.

If this was my setup I do not think I would be able to sleep at night wondering when things were going to let go and dump into my sump.

[incapearl]

oh man! I guess I'll figure out a glass box

[ca1ore]

I did something quite similar and it lasted fine - until I whacked it reaching into the tank one time and it just fell off. What I did then was to glue a full back onto the box using a piece of acrylic cut to size with holes matched to the ones on the glass tank, sandwich the acrylic between the bulkhead flange and the glass tank with silicone sealant between the acrylic back and the glass. Never fell off after that!

[incapearl]

I did something quite similar and it lasted fine - until I whacked it reaching into the tank one time and it just fell off. What I did then was to glue a full back onto the box using a piece of acrylic cut to size with holes matched to the ones on the glass tank, sandwich the acrylic between the bulkhead flange and the glass tank with silicone sealant between the acrylic back and the glass. Never fell off after that!

How long did it last before you accidentally hit it and it fell off?

[breadfan]

I did something quite similar and it lasted fine - until I whacked it reaching into the tank one time and it just fell off. What I did then was to glue a full back onto the box using a piece of acrylic cut to size with holes matched to the ones on the glass tank, sandwich the acrylic between the bulkhead flange and the glass tank with silicone sealant between the acrylic back and the glass. Never fell off after that!

That is what I was thinking. Just put a back on the box and use bulkhead washers on both sides of the glass. Basically make it like a glass-holes overflow box.

[incapearl]

That is what I was thinking. Just put a back on the box and use bulkhead washers on both sides of the glass. Basically make it like a glass-holes overflow box.

I think I'll leave it the way it is. So when and if it starts to come off, I'll make it a complete box. Just have to make sure I keep an eye on it.

As far as making it like a glass holes box... Would algae grow between the box and the tank that I'd have to clean?

[ca1ore]

How long did it last before you accidentally hit it and it fell off?

There isn't a lot of stress on the joints if you keep the water level high inside the oveflow box and aren't clumsy like me. Mine lasted about 5 years before I knocked it off.

[sleepydoc]

+1 to the above comments. Silicone will not bond to acrylic long term. As Ca1ore said, the water pressure and adhesion that you do get from the silicone may be enough keep it in place, and as long as it's not going to cause a disaster if it lets loose, you could just leave it.

Another option is to add a back to it with a hole that matches the hole in the tank and either orient the bulkhead so the flange & gasket are on the outside, or add a gasket between the tank and overflow wall.

[Da Maui life]

I just siliconed my acrylic overflow to my glass aquarium. I used GE silicone 1. Is this going to work]
I would not trust silicone on acrylic, and dump the teeth on your box as it cuts down on skimming capacity.

That is what I was thinking. Just put a back on the box and use bulkhead washers on both sides of the glass. Basically make it like a glass-holes overflow box.

Although my tank is acrylic I build a five sided overflow box ‘removable.’ As you mentioned it requires two gaskets, one in-between the back panel and back of overflow box, one on the inside of the overflow box.
http://i126.photobucket.com/albums/p89/mauilife/BAOVERFLOW002_zps4412d43a.jpg
http://i126.photobucket.com/albums/p89/mauilife/2013-09-13102537_zps2a41945c.jpg
http://i126.photobucket.com/albums/p89/mauilife/2013-09-20113248_zpsa96a5629.jpg

[incapearl]

I think I'll just leave it and plan my sump accordingly for now. After removing the braces from siliconing, it was extremely sturdy and bonded well to the glass...for now, I know. But I think it'll be fine. Here's the finished product.
http://i1364.photobucket.com/albums/r737/ian50moss/Reef%20Tank/image_zps888fdfb1.jpg

http://i1364.photobucket.com/albums/r737/ian50moss/Reef%20Tank/image_zpsba96d7a4.jpg

http://i1364.photobucket.com/albums/r737/ian50moss/Reef%20Tank/image_zps8edf37fd.jpg

[Da Maui life]

Schnikes, could be my eye’s but the holes look too close together for my comfort.

[incapearl]

Schnikes, could be my eye’s but the holes look too close together for my comfort.

They aren't. I drilled them at least as far apart as the hole diameter

[incapearl]

Btw da Maui life. Where in Maui are you? I was just there for 10 days. Stayed at kaanapali beach. Awesome snorkeling!

[sleepydoc]

I think I'll just leave it and plan my sump accordingly for now. After removing the braces from siliconing, it was extremely sturdy and bonded well to the glass...for now, I know. But I think it'll be fine. Here's the finished product.


It seems sturdy now, but won't stay that way. As long as you plan accordingly....

[Da Maui life]

They aren't. I drilled them at least as far apart as the hole diameter
I think it's 1.5 x dia.

Btw da Maui life. Where in Maui are you? I was just there for 10 days. Stayed at kaanapali beach. Awesome snorkeling!

I’m on the south side, your stay was the far side as we call it. Yes very nice snorkeling in that area.

[Bretts05jeep]

Wish I didn't open this one. Just put the same box in my glass tank. Now I don't know what I am going to do. At least I don't have water in the tank yet.

http://i1102.photobucket.com/albums/g460/br600rr/SAM_2940.jpg (http://s1102.photobucket.com/user/br600rr/media/SAM_2940.jpg.html)

http://i1102.photobucket.com/albums/g460/br600rr/SAM_2939.jpg (http://s1102.photobucket.com/user/br600rr/media/SAM_2939.jpg.html)

http://i1102.photobucket.com/albums/g460/br600rr/SAM_2938.jpg (http://s1102.photobucket.com/user/br600rr/media/SAM_2938.jpg.html)

[kegogut]

If using silicone to adhere overflows to glass,why do all the manfucturers do it?

[karimwassef]

Don't use GE silicone. Use GOOP.
You need an adhesive element that is not present in silicone alone.

[kegogut]

I plan on using some gorilla super glue to glue mine to the glass before I use the silicone. Ill check on the goop too though.

[karimwassef]

Goop is an adhesive and sealant. I've used it to construct aquariums before.

[JVJordan]

There is next to no adhesion between silicone and acrylic.

[karimwassef]

It's not between acrylic and glass. The GOOP sticks to both, they don't stick to each other.

[kegogut]

Ive decided to use the GOOP to adhere/seal it to the glass,will post results!

[karimwassef]

Make sure to give it plenty of time to cure. If it turns cloudy when you wet it, then you didn't give it enough time.

[IUfan]

I can't tell if this is referring to internal or external overflow box.

If internal, you guys have nothing to worry about.

I had an acrylic box made by melev, was 4' across, used reef safe silicon, put a bead of it across all the contact edges, pressed it down, wiped the excess off with my finger, left for 24hrs with weight on it, job done!

I could yank on it very hard and it stuck fine, even filled just the overflow box with water whilst the rest of the aquarium was dry and never leaked or even once looked like coming apart!

I've ran it like this for over a year now, no issues, never even raised a concern for me.

As a side note, my tank originally came reef ready, so I had to tear the existing overflows out to go to a semi coast to coast. The experience of trying to tear that out gives me a lot of confidence in the silicones ability to hold in this application, it was a nightmare to pry the overflow boxes out of the tank.

Hope this info helps.

[incapearl]

I can't tell if this is referring to internal or external overflow box.

If internal, you guys have nothing to worry about.

I had an acrylic box made by melev, was 4' across, used reef safe silicon, put a bead of it across all the contact edges, pressed it down, wiped the excess off with my finger, left for 24hrs with weight on it, job done!

I could yank on it very hard and it stuck fine, even filled just the overflow box with water whilst the rest of the aquarium was dry and never leaked or even once looked like coming apart!

I've ran it like this for over a year now, no issues, never even raised a concern for me.


As a side note, my tank originally came reef ready, so I had to tear the existing overflows out to go to a semi coast to coast. The experience of trying to tear that out gives me a lot of confidence in the silicones ability to hold in this application, it was a nightmare to pry the overflow boxes out of the tank.

Hope this info helps.

It's internal and thank you for the reply. Same here, when I put it on and let it set for 24 hrs, it seemed impossible to pull off. My tank has been running for just over 6 months and have had zero concerns about it.

[sleepydoc]

If using silicone to adhere overflows to glass,why do all the manfucturers do it?

2 differences:
First, the overflows that you see manufacturers put in are made from PVC, not acrylic. Different material, different adhesive properties.

Second, they are generally are corner overflows that run the full depth of the tank. That means there is more water pressure holding them in place and the silicone itself will wedge them in place.

[Wryknow]

I imagine you'd do better with a better quality silicone as well. RTV-107 or RTV-103 seems to be the stuff professional aquarium builders use and recommend. GE Silicone 1 seems to have a pretty low adehesion strength. As Sleepydoc pointed out - on a full length overflow the water pressure actually helps hold everything in place.