# How to stick Styrofoam together?



## Derek Layton (Apr 23, 2009)

I am completely redoing a 125 that I got off of CL and want to start a DIY BG. I really like the way Amazilia made her BG.





http://www.cichlid-forum.com/phpBB/viewtopic.php?t=200798&postdays=0&postorder=asc&&start=45

She cut different shaped strips out of the Styro and glued them together. I like the way it looks, the depth you can see while still not taking up a lot of tank space and think that it will also work well with some of the other features I am want in the tank.

I am planning to cut the pieces, glue them all together, and then carve out the spaces for the filters, overflows, etc.

My question isÃ¢â‚¬Â¦ Is silicone the best thing to use to glue the Styro to itself? I want to make sure that the structure is well sealed to itself before a start treating like it is one large piece. I know that Amazilia used silicone.

I also want to make sure that my BG, or parts of it, do not end up shooting out of the tank. 
What are my options? Any advice would be great.
-Derek-


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## FlyHigh (Nov 15, 2009)

Whatever adhesive you wind up using. Don't skimp out on the amount that you use. Use very generous amounts.


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## Mcdaphnia (Dec 16, 2003)

Synthetic yarn holds it together more dependably than glue. It's what the killifish and rainbowfish people use to make spawning mops for their fish. Wrap it where possible and stitch through with a knitting needle in the concave parts. The yarn on the surface helps hold whatever coating you use so that it won't chip off later, so the more wrapping the better.


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## NuFish (Aug 10, 2010)

I use the "The Great Stuff"; It works wonders!

NuFish


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## TheFishGuy (Apr 21, 2005)

Mcdaphnia said:


> Synthetic yarn holds it together more dependably than glue. It's what the killifish and rainbowfish people use to make spawning mops for their fish. Wrap it where possible and stitch through with a knitting needle in the concave parts. The yarn on the surface helps hold whatever coating you use so that it won't chip off later, so the more wrapping the better.


+1


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## Malawi_Junkie (Nov 26, 2009)

I prefer silicone, quick and easy. As mentioned above use plenty coating the entire surface then add weight and allow to cure


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## Mcdaphnia (Dec 16, 2003)

Malawi_Junkie said:


> I prefer silicone, quick and easy. As mentioned above use plenty coating the entire surface then add weight and allow to cure


Maybe in some sense easy, but definitely not quick. You can start coating the foam you have stitched together with synthetic yarn the second you finish.

You will have to wait until the silicone cures, which may take hours or even days, slowing down the job, making it anything but quick.

And compared to wrapping and stitching, not really easy, either.

Plus the end result flexes, because silicone is permanently flexible. That can encourage chipping of the coating, and shearing of the attachment points that hold it underwater.


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## TheFishGuy (Apr 21, 2005)

True, nothing sticks to cured silicone.


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## Malawi_Junkie (Nov 26, 2009)

It only took me 10 min to attach 4 8ft x 2ft x 1" sheets with silicone. cured 24hrs and done. The very little amount of silicone that was exposed after carving covered just fine with Drylok which is Latex and also flexible in the end result. I'm pretty sure I couldn't have stitched them together in 10 min. Not to mention when carving through the styro I would have cut the yarn in several places weakening the bond. Now in this case he wants to stack strips so I can see how this would work. Almost every DIY styro BG I've seen has used silcone to bond together styro and I can't seem to recall a single one that has used the yarn method. I'm sure they're out there but silicone seems to be the preferred method.


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## Mcdaphnia (Dec 16, 2003)

Malawi_Junkie said:


> It only took me 10 min to attach 4 8ft x 2ft x 1" sheets with silicone. cured 24hrs and done. The very little amount of silicone that was exposed after carving covered just fine with Drylok which is Latex and also flexible in the end result. I'm pretty sure I couldn't have stitched them together in 10 min. Not to mention when carving through the styro I would have cut the yarn in several places weakening the bond. Now in this case he wants to stack strips so I can see how this would work. Almost every DIY styro BG I've seen has used silcone to bond together styro and I can't seem to recall a single one that has used the yarn method. I'm sure they're out there but silicone seems to be the preferred method.


 I am not sure that anyone has tried both and had a preference. Preferred may be not quite the term. Maybe it is the traditional or popular method. Maybe it's the only one most people have heard of.

Gluing might have an advantage if you are making changes to the design as you go. You should plan ahead with yarn on the outside of the foam. That way if there is a place you might trim or add a tunnel, you would run the yarn accordingly. If the way you make your design is totally fluid and you don't know what it is going to look like until it's done, glue might fit your creativity.

but if you don't like the coating chipping off and exposing the styrofoam, yarn is appealing. It does the same thing stucco backing or brick ties do to hold mortar in place.


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## Derek Layton (Apr 23, 2009)

OK, I had read somewhere that someone (how specific, right?) that hey used some sort of spray adhesive that worked really well, but that it got really expensive.

Where do you buy the thread? Is it expensive?
Do you know of anyone that has posted pictures of them using it?

I have another question. What foam does everyone use.
It seems that most people use white foam of some sort, but the only large sheets that I could find in my small town are the blue ones.

Are these the same? Pros and Cons?

Where do you find large sheets (i.e. 4x8 or so) of the white foam?

I have been taking pictures of the stand and filter build and will start a total build thread as soon as I get started on the background.

Thanks for the help.


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## R-DUB (Jun 3, 2007)

Gorrilla Glue works fantastic on white to white styro.


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## TheFishGuy (Apr 21, 2005)

> Where do you find large sheets (i.e. 4x8 or so) of the white foam?


Home depot by the insulation.


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## Ed_209 (Dec 22, 2004)

Plus 1 for great stuff. Bonds styro to styro better than silicone.


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