Siliconing Rocks to acrylic

[Itchy Trigger]

I'm going to be covering an acrylic overflow box with flat cut rocks from the Reef Rock Store. Planning to use silicone to attach them. In terms of strength, which silicone would be best to use here? GE type I? Or a silicone specifically rated for aquarium use? I know the GE stuff is safe to use; just want to be sure I use the strongest possible adhesive here. Any recommendations? Is there a better option than silicone altogether?

 

[Crusinjimbo]

I used GE type 1 on a Silat project three years age. Rock remains solid on the wall with no noted ill effects. It must get into the pores of the rock. Adhesion between flat rock and glass wasn't great. Gorilla glue might also be a good choice.

 

[Itchy Trigger]

Interesting about gorilla glue. Hadn't considered that but it's great and super strong.

 

[Itchy Trigger]

How about this stuff? Looks like it cures fast and a local guy was telling me it is super strong:

http://www.bulkreefsupply.com/ecotech-coral-glue-1.html

 

[lFATHOMl]

try jB Water weld it's good stuff. Lots of positive reviews and i've had great experiences with it as well

 

[Gorgok]

You have to remember its acrylic you are trying to attach stuff to. Silicone won't really hold, nor will many glues. I would look for a more mechanical solution, like a shelf on the overflow or 'rings' for zip ties or similar attached to the overflow.

 

[Itchy Trigger]

That's certainly a good point, Gorgok. One thing I thought to do was basically build this up from the bottom, and use the lower rocks as foundation for the higher pieces, with the silicone/glue between the flat backs and the acrylic being for added stability. Someone suggested I use Great Stuff to fill voids between rocks as I build up this way, but I hate the way that stuff looks and would rather not see it even for the few months it would take for it to get covered up. I suppose I could use some sort of epoxy instead. I've got some EpoPutty on hand for building pillars/islands. Perhaps I'll use that. Any other suggestions? Maybe something that works like Great Stuff but doesn't look quite as hideous? Pond foam?