Silicone

[Ehcosbie]

I have a cyanoacrylate glue join between wood and rock that keeps failing, I am thinking of using silicone at this point, but it would need to be able to set underwater. Would normal, clear silicone set underwater?

Thanks all.

 

[Dogtemple]

Silicone needs the air to set and it won’t stick to anything wet. So probably no good if you can’t take this thing out of the tank

 

[OllieTY]

Can you drain the tank down so that the join is exposed before gluing?

 

[zozo]

TEC7 is a non-toxic polymer sealant that does cure underwater, but its curing time still can make it a tad difficult to keep stuff in place.

Tec7, the unbeatable number 1 in bonding, mounting and

Simply works.

tec7.com

I did repair leaking aquariums with it in the past and use it often in the garden (ponds)... But then it's still advisable to drain it partially to apply it and give it some time to cure. Then if it's drained anyway in the case of hardscape it will be easier and faster to use super glue./ cyanoacrylate. The thing is cyanoacrylate reacts with and actually needs moist (water) to cure. It doesn't cure without it... That's why it won't work submerged because it will instantly cure.

Also if partially drained then take the GEL type and not the liquid type cyanoacrylate and it will stick in seconds and you are ready to fill it up again.

 

[Simon Cole]

I have used underwater epoxy putty in the past, but all livestock should be removed first if you do this, and it it will cause the water to go a bit murky - so you will need a water change afterwards anyway.

 

[ian_m]

Silicone needs the air to set and it won’t stick to anything wet.

Acetoxy silicone (the one that smells of vinegar) requires water/moisture to set, so will set under water, though is difficult to work as it quickly skins over underwater whilst "playing" with it

Neutral cure does not release vinegar whilst setting.

Be careful a lot of silicone has fungicide in it, so your sealed bath doesn't go mouldy and is probably not suitable for aquatic use. Though nobody told the peeps 40 years ago odd who regularly used silicone with fungicide in to seal the panes of glass against steel tank frame. Fish lived. I assume the fungicide stays in the silicone rather than leech out into the water.

I have used this to glue rocks underwater. Work's'ish fine... But after a year or two did come apart, better than silicone.
JBL PROHARU UNIVERSAL

In my experience rocks no matter what glues them, eventually come apart, the water seeps its way under the silicone slowly. The best I had was I stainless steel bolted slate together with silicone. That never fell apart, but when removed from the tank for cleaning it was obvious the silicone was slowly coming away from the slate.

 

[tam]

There are some products designed for underwater use e.g. Aquascape Epoxy | D-D The Aquarium Solution

I would suggest preping for a water change post using them though.