glueing tiles together

Any silicone will work but it has to be pure silicone. Many of the silicones at home depot etc... have things added to prevent mildew or mold. Avoid those ones. The stuff at most fish stores is generally more expensive but you can be pretty sure that it is safe. And for small caves etc... you won't need very much so a small tube will go quite far.
 
Walmart sells aquarium safe pure silicone in a tube for about half to a third of what you'll pay at most lfs or Petsmart/co.

You can get large caulking gun cannisters at Home depot but that's a touch of overkill if you're just glueing rocks.

It takes a while to set so male sure you have a place for the new caves to cure our of harms way. Its not like superglue either. A little tends to NOT go a long way. Small dollips will hold the rocks together but when you move them afterwards be sure to support the weight of the rocks from the bottom.

Tom
 
Well.. its not really for making caves.
I just want to glue together a rectangular "flowerpot" to put some substrate and a plant in. Its not going to bear any weight or be a hazard (tumbling over and busting my glass).
I had some silicon lying around, but it specifically stated "NOT FOR AQUARIUM USE"... so.. thats out of the question.
I'll go to Wal mart and find some cheap silicon or epoxy
 
Be careful of your epoxy choices. Most cheap epxoies will end up deteriorating under water pretty quicky. You really need marine quality or else perhaps epoxies for car engines to survive under water for any length of time.
 
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