# Glue for styrofoam that is aquarium safe? Help.



## flashbang009 (Aug 6, 2009)

Hi all,

I'm trying to glue multiple sheets of styrofoam together that will be used to create artificial rocks (eventually covered with grout to seal the styrofoam), and i can't seem to find a good/non-lethal glue to use to join the styrofoam. Hot glue is safe, but i can't glue up an entire sheet before the darn stuff hardens. I'm trying to find my aquarium safe silicone, but i can't at the moment. Any other suggestions? I just don't know what would work well and be safe.

Thanks.


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## Diana K (Dec 20, 2007)

I got something called Foam board adhesive, in a caulking tube. I have no idea if it is
a) waterproof
b) fish/plant/invert safe. 

It IS labeled as a glue for Styrofoam. 

I was going to add Sikatop waterproof and food safe product as a coating. I am sure water would get in there, though. 

Aquarium safe silicone is usually 100% silicone for windows and doors (and other construction use) but not for bathrooms. Sometimes these bathroom caulks have mildew resistant chemicals in them that are not good in an aquarium. 

GE I is one of them, 
I have seen DAP aquarium silicone in some fish stores. 

The products labeled for aquariums have been tested for aquarium use. The products that say "Not for aquarium use" MIGHT be OK, but have not been tested, and the manufacturer does not want the liability, or the cost of testing for such a small market. Also, they might be the ones with mildew inhibitors, which are really not for aquarium use. 

Now... whether silicone will bond styrofoam is another question...


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## flashbang009 (Aug 6, 2009)

Well, i ended up using the GE 100% Silicone I. It seems to bond well, i'll check tomorrow once it is cured. I'm not too concerned, because it'll eventually be covered with quikrete, or grout, which should hold it all together. So it just needs to hold up through the carving process (i do too! ). Thanks for the info.


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## Noto (Oct 26, 2009)

I've used expanding urethane products, such as Gorilla Glue and Great Stuff, to join polystyrene sheets. Works like a charm. You just have to weight the styrofoam so the expanding urethane doesn't create gaps between the sheets.


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## goldier (Feb 13, 2010)

I also plan to make some artificial rocks. I read the super glue is safe to use, so that's another option.


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## flashbang009 (Aug 6, 2009)

Yeah, super glue was an option, i've used it plenty of times for other applications. The only problem is that i had to glue 11 sheets of 3 foot by 2 foot styrofoam together haha. Superglue would be close to impossible to use for that. 

I'm ready for the carving, but i'm kinda nervous about it haha, i don't want to mess up the design.


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## Big_Fish (Mar 10, 2010)

epoxy. 
(same stuff they make submersible pumps waterproof with)

5 minute cure time if you're in a hurry.  

I fly RC airplanes... use this stuff EVERYDAY.


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## goldier (Feb 13, 2010)

flashbang009 said:


> Yeah, super glue was an option, i've used it plenty of times for other applications. The only problem is that i had to glue 11 sheets of 3 foot by 2 foot styrofoam together haha. Superglue would be close to impossible to use for that.
> 
> I'm ready for the carving, but i'm kinda nervous about it haha, i don't want to mess up the design.


Ya, that's a lot to glue. For light materials like that, we can spot-glue them, dropping pea size glue every 3-4 inches without spending a lot of glue, no?

Have fun carving. Maybe you can practice on some styrofoam piece to get a feel. You can also make some erosion style by using a hot soldering iron tip and press it lightly at the styrofoam surface at varying angles.

What kind of polymer are you using to mix with the grout?


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## flashbang009 (Aug 6, 2009)

I'm not sure off the top of my head. It's all covered on this site. Practicing carving is definitely something i'll do. I'm going to use a heat gun similarly to how you described too.

Thanks for the tips.


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## default user (Feb 9, 2010)

Any type of gel super glue, or GE I 100% silicon. Make sure its doesn't have any mold or mildew inhibitors in it. Its the same stuff that all glass aquarium sells from twice the price.


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## flashbang009 (Aug 6, 2009)

yeah the ge is what i used.


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