Using epoxy in an established aquarium

[WhistlingBadger]

The shelves on my waterfall fell off last night. Again. I keep gluing them on with silicone, but I think the high humidity keeps the surfaces from ever completely drying out. So, I will try, try again, and maybe ventilate a little better this time so things stay dry.

I'm wondering about using epoxy. While curing, it gives off some fumes that do NOT smell healthy. Would these fumes get into the water and harm the fish? Any insights?

 

[MaloK]

Max Epoxy Systems MAX ACR A/B is an aquarium safe epoxy.

I would not use standard epoxy, even near my tanks.

 

[WhistlingBadger]

What about gorilla glue? It adheres to damp surfaces.

 

[MaloK]

Some people say it's ok once cured, but Gorilla itself does not recommend their product for use in aquariums.

 

[WhistlingBadger]

I'll probably just try silicone again, and be more careful to have everything perfectly clean and dry.

 

[Seisage]

There's a 2-part epoxy putty called Splash Zone which we've used in marine research for holding things down. You can apply it underwater and it holds really well. That said... I don't think it's particularly animal-safe. We let it cure for a day or two before putting animals in, but it does work well. Maybe it would be fine if you turned off the waterfall while it cured.

In searching for that brand name though (I had forgotten it), I did find a putty epoxy stick made by Instant Ocean that's meant for holding down corals, plants, live rock, etc. It's pretty cheap on Amazon so maybe that'd work better. It's clearly safe for aquarium use, given the company that makes it, although it may also have a cure time.

 

[rebe]

What about gorilla glue? It adheres to damp surfaces.

Jumping in here, but any superglue that is just cyanoacrylate is fish and aquarium safe. It's used in human and veterinary medicine too!
Water actually speeds up the "drying" process, so it won't dissolve. Any fumes from cyanoacrylate become inert once they come into contact with moisture. Sometimes the label will have a longer name, but it's the same stuff. These are the longer names, from a Wikipedia page:

"Specific cyanoacrylates include methyl 2-cyanoacrylate (MCA), ethyl 2-cyanoacrylate (ECA, commonly sold under trade names such as "Super Glue" and "Krazy Glue"), n-butyl cyanoacrylate (n-BCA), octyl cyanoacrylate, and 2-octyl cyanoacrylate (used in medical, veterinary and first aid applications). Cyanoacrylate adhesives are sometimes known generically as instant glues, power glues or superglues. The abbreviation "CA" is commonly used for industrial grade cyanoacrylate."

I've never used any epoxy or silicone, but I use cyanoacrylate glue for loads of things in my tanks. Sponge prefilters, attaching plants, and I've even superglued hardscape against the aquarium wall when it was floating too much! That was in my 280, which I don't intend to rescape. The glue can be scraped off with something like a razor blade though if need be

 

[WhistlingBadger]

Jumping in here, but any superglue that is just cyanoacrylate is fish and aquarium safe. It's used in human and veterinary medicine too!
Water actually speeds up the "drying" process, so it won't dissolve. Any fumes from cyanoacrylate become inert once they come into contact with moisture. Sometimes the label will have a longer name, but it's the same stuff. These are the longer names, from a Wikipedia page:

"Specific cyanoacrylates include methyl 2-cyanoacrylate (MCA), ethyl 2-cyanoacrylate (ECA, commonly sold under trade names such as "Super Glue" and "Krazy Glue"), n-butyl cyanoacrylate (n-BCA), octyl cyanoacrylate, and 2-octyl cyanoacrylate (used in medical, veterinary and first aid applications). Cyanoacrylate adhesives are sometimes known generically as instant glues, power glues or superglues. The abbreviation "CA" is commonly used for industrial grade cyanoacrylate."

I've never used any epoxy or silicone, but I use cyanoacrylate glue for loads of things in my tanks. Sponge prefilters, attaching plants, and I've even superglued hardscape against the aquarium wall when it was floating too much! That was in my 280, which I don't intend to rescape. The glue can be scraped off with something like a razor blade though if need be

In my experience, cyanoacrylate glues are very handy, but when submerged they become very brittle over time and eventually give way if they're stressed. They also only work on smooth surfaces. Extremely effective for limited applications, but not the right tool for this job.

By the way, it IS great for human medicine! Back in my rock climbing days, I knew big-wall climbers who always carried a tube of super glue in their chalk bags for closing cuts. Effective stuff!

 

[davros]

Is there any way to lock those parts or create a keyway to reduce reliance on glue? Drill, dowels, supports...

 

[WhistlingBadger]

Is there any way to lock those parts or create a keyway to reduce reliance on glue? Drill, dowels, supports...

Good idea. I have tried using toothpicks, and one is held in place with a bit of steel mesh under it. Might run to the hardware store and buy a spool of stuff, stainless steel wire to hold things in place.

But I think I figured out the problem. In the past, I blotted the fake rocks dry with paper towels and glued things on. This time, I'm letting everything thoroughly air-dry. I turned off the waterfall last night, and judging by the minerals visibly precipitating out of the water, it still isn't fully dry yet. This Drylok surface is waterproof, but apparently the textured surface holds a LOT more moisture than I imagined. Though it was dry to touch, I think I was gluing onto a damp surface. I'm going to allow it to continue air drying until tomorrow morning, they do my gluing, and I bet it will take.

 

[Magnum Man]

I have used this stuff in aquariums sticks to wet surfaces, says instantly water proof… as a user, it won’t hold a lot of weight while it’s wet, and it stays somewhat flexible when it dries, it does take a while to dry, and is kinda stinky… I’ve not to use it in a functioning aquarium… I’ve used it to glue things that I put in the tank the next day

 

[WhistlingBadger]

That Lexel is tough stuff! I've used it to calk bathrooms. Takes a long time to cure, and I'm not sure how aquarium safe it is. Usually adhesives with mildew inhibitors aren't safe for fish.

 

[StevenF]

I used 5 minute epoxy to modify a filter. The filter was not in the tank and dry when I applied epoxy. I gave it a few days to dry and then cleaned it before putting it in the tank. Saw nothing with my fish and shrimp to indicate a problem.