# Using "Great Stuff" to glue the background?



## Ed_209 (Dec 22, 2004)

I'm making my first attempt at a 3d concrete background for a 125 gallon.
I siliconed 2 sheets of styrofoam together using "GE Construction 1200 series"
Did some carving and I noticed some pieces were coming loose. The silicone doesn't adhere well to this styrofoam. (It's the stuff that breaks into little balls.)
With a small bit of pressure I can pull apart the pieces. I can't see silicone keeping this much styro submerged.
I finally found some expanding foam for ponds(Touch 'n Foam Landscape from Lowes) and glued all the loose pieces back together. The foam is black and the can says it's safe for fish.

I did a small test to see how well it would adhere to glass.
An old glass lid I stepped on and a scrap of styrofoam glued together with foam.
It's on there hard. I pulled and twisted but they won't come apart.
Pried it off and the styro broke.


























I think I might buy a couple more cans to fasten the background to the tank.


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## Mcdaphnia (Dec 16, 2003)

I found sewing or wrapping the foam pieces together with nylon yarn works better than silicone or glue. Plus the yarn helps the concrete coating from falling away. Still better would be to just use the landscape foam to create the whole background in place. If you want you could insert some real rocks and driftwood into the foam while the tank rests on its back and the foam cures. When this foam cures, it is porous, so you can use it as a denitrator. Stand a long skinny party balloon knot end up on the back of the tank. Foam in the background, and once cured pop the balloon and pull out the pieces. Or put in a panel of the styrofoam you have then gouge it all out. Drop an airstone in the hole and carve a spillway to the front. The very small current generated through the background will encourage bacteria that convert nitrates to nitrogen.

This is probably the best choice of background if you have a tank where the fish grow rapidly or the population load changes overnight due to stock transfers.


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## Ed_209 (Dec 22, 2004)

An entire background made of this foam would be decent. It costs 10.15 per 16oz (454 g).
There's nothing on the can that says how much volume of foam is inside but a can doesn't go too far...
Much better than using silicone for the carving,and for fixing mistakes. Tack free in 30 minutes,and cures in 4 hours.
I'll be saving my extra tubes of GE1200 for a tank reseal.


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## Mcdaphnia (Dec 16, 2003)

One drawback to the landscape/pond foam is that once you start the can, you might as well use it all. Saving a partial can does not always work, even when you use it for a project a few days later. Setting up several projects at once can help reduce the waste.

Especially when not compressed, like when between rocks, landscape foam expands to several time its original bead size. One of the pond stores here had a display where they squirted out an entire can on a table top then stuck the empty can in the mound of foam. It looked pretty big.


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## Ed_209 (Dec 22, 2004)

I think one thing I did wrong was hold the can like it was a can of spraypaint. I noticed later it said "This end up" on the bottom.


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## R-DUB (Jun 3, 2007)

Use "Gorilla Glue" to bond styro together. Works perfect and is 100% waterproof. It "foams" slightly while curing. Curing takes just a few minutes. Good Luck!
:thumb:


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## Ed_209 (Dec 22, 2004)

Hello R-Dub, I've read some of your posts about backgrounds,and also Mcdaphnia's posts. 
How safe is Gorilla Glue for fish? When I coat the background with concrete,I'm not sealing it with epoxy resin.
Just going to do the water changes for a month.

I just started the concrete phase. Got 75% done from a 5kg pail. I'm off to HomeDepot for another 15kg.

Edit: I just did a search about Gorilla Glue. Totally non toxic after it cures.
http://www.gorillatough.com/ToughTe...forumid/4/postid/100/scope/posts/Default.aspx


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## mightyevil (Oct 23, 2008)

Ed_209 said:


> Just going to do the water changes for a month.


You don't have to make water changes or a month!!! All you have to do is make sure your PH is stable before adding fish and let the tank cycle of coarse. You can do a few 100% water changes and your PH might be fine, just keep testing until your PH reaches your desired level. No need to make water changes for a month :lol: .


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## Mcdaphnia (Dec 16, 2003)

Ed_209 said:


> Hello R-Dub, I've read some of your posts about backgrounds,and also Mcdaphnia's posts.
> How safe is Gorilla Glue for fish? When I coat the background with concrete,I'm not sealing it with epoxy resin.
> Just going to do the water changes for a month.
> 
> ...


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## Ed_209 (Dec 22, 2004)

I'll probably let it cure for a few weeks. 
For the cycle,I'm going to use the filters off my 72 gallon.Eheim 2028,and I'm also adding an Aquaclear 110. I've got 3 AC110 with 2 bags of media in each one. I'll probably swap one bag out and put it in the new tank.
There will be 3 grown Calvus,11 juvenile Fronts and a few Dickfeldi in there.


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## R-DUB (Jun 3, 2007)

The GG does have awesome strength. McDaphnia is correct 100% safe after cure. Clamping is not totally necessary. Dampening the two pieces to be glued helps to make the glue dry quicker. Im telling ya use DRYLOK! Way easier than crete. IMHO. Good Luck! More pics please!!
P.S. BG looks very nice, great start. Kudos!
:thumb:


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## Ed_209 (Dec 22, 2004)

I finished the concrete and glued it in the tank with Landscape Foam. Hope it holds.
I've filled it with water to see if it comes shooting out of the tank. So far it's staying put.
I've been reading a bit about concrete curing. It seems it's better for it to cure underwater.
Once I add in some Anubias plants and get some algae growth,it should look alright.

I dropped in a powerhead and a PH monitor as well. Started out at 7.5 and 3 hours later,it's up to 8.5
I used 20 kilos (44 pounds)of King Swift Set concrete. I'm curious to see how high it will go.










Same picture but higher resolution.


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## Mcdaphnia (Dec 16, 2003)

Ed_209 said:


> .....
> I've been reading a bit about concrete curing. It seems it's better for it to cure underwater.
> .....


 Are you reading the few aquarists who are convinced they've found a magic way to cure concrete that has been missed by all the concrete professionals and researchers for the last few centuries?

Unless you are using a hydraulic cement, and you may not want the chemicals incorporated in that kind of cement in your tank, you will get better results curing in air for 30 days. Avoid the problems with premature disintegration, persistant high pH and hardness that the underwater cures have.


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## Ed_209 (Dec 22, 2004)

No,didn't get the idea from any aquarists. Just did a search for "underwater concrete curing".
I found this site:
http://www.cement.org/basics/concretebasics_faqs.asp
There's quite a science to concrete.
I won't have my canopy finished for a couple more weeks,so no fish are going in for a some time.


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## mightyevil (Oct 23, 2008)

Ed_209 said:


> No,didn't get the idea from any aquarists. Just did a search for "underwater concrete curing".
> I found this site:
> http://www.cement.org/basics/concretebasics_faqs.asp
> There's quite a science to concrete.
> I won't have my canopy finished for a couple more weeks,so no fish are going in for a some time.


Well, that was interesting!

My method has worked for me, I will use it until someone can tell me "I told you so"...lol, I'm just too impatient!


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## Ed_209 (Dec 22, 2004)

Yeah,I found one site about how the Romans made concrete and how some of their concrete is still there 2100 years later.
If I try this again I'm going to find a Canadian equivalent of DryLok.
I've been to Rona,Home Depot,and Lowes.No luck.

My PH has been at 8.9 for the last 3 hours.


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## Mcdaphnia (Dec 16, 2003)

Ed_209 said:


> No,didn't get the idea from any aquarists. Just did a search for "underwater concrete curing".
> I found this site:
> http://www.cement.org/basics/concretebasics_faqs.asp
> There's quite a science to concrete.
> I won't have my canopy finished for a couple more weeks,so no fish are going in for a some time.


 That site does not suggest at all that underwater curing is best. In fact to quote it, 
"Every desirable physical property that you can measure will be adversely effected by adding more water."


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## Ed_209 (Dec 22, 2004)

That's not the only site I read about concrete at. I found a couple of others as well.
I'm not trying to convince you it's best. Just showing you where I got that idea.
Contractortalk.com
ScienceDirect:"Test results indicated that concrete under water curing offers the best results".
That last one is just an abstract,the entire paper costs 30.00+

Your quote is part of how to make the concrete stronger at the mixing/paste stage:

_"How do you control the strength of concrete?
The easiest way to add strength is to add cement. The factor that most predominantly influences concrete strength is the ratio of water to cement in the cement paste that binds the aggregates together. The higher this ratio is, the weaker the concrete will be and vice versa. Every desirable physical property that you can measure will be adversely effected by adding more water. "_

I think my concrete for this project will be pretty weak(as compared to construction quality). I used a lot of water to be able to get it in all the nook and crannies.


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## Ed_209 (Dec 22, 2004)

McDaphnia,when you added the oak leaves,you just toss them in the water? Would any leaves do the same thing?? Got a Maple tree I could try.


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## Ed_209 (Dec 22, 2004)

Here's a tip. Don't pull apart any pieces of Great Stuff underwater once you put fish in the tank.
I've got a couple of test fish in there.1 inch calvus'.
I pulled apart a piece of black foam that expanded into the opening where a filter intake is going.. Some bubbles escaped and I'm guessing it was some toxic gas. Within a minute one of the calvus started doing loops and died a minute later.

The PH is staying at 8.1 after 5 days.


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## Mcdaphnia (Dec 16, 2003)

Ed_209 said:


> Here's a tip. Don't pull apart any pieces of Great Stuff underwater once you put fish in the tank.
> I've got a couple of test fish in there.1 inch calvus'.
> I pulled apart a piece of black foam that expanded into the opening where a filter intake is going.. Some bubbles escaped and I'm guessing it was some toxic gas. Within a minute one of the calvus started doing loops and died a minute later.
> 
> The PH is staying at 8.1 after 5 days.


This stuff is semi-permeable, so it acts like a denitrator after a while, if you have some flow through it. If the flow though it is too slow it will deplete of all oxygen. Then anaerobes will colonize inside it and if you break it up, you'll release hydrogen sulfide gas. Aeration, or more extreme, ozone or hydrogen peroxide dosing will help neutralize the hydrogen sulfide and eliminate the anaerobes.


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