View Full Version : Filling in gap between 2 foam rock wall sheets?

10/02/2017, 05:22 PM
Had to make a separate smaller foam rock wall piece for my back wall so I could get it in the tank. (Eggcrate with dry rock and pond foam).

I'd like to fill the gap between the 2 pieces to make it look like one piece (will be putting epoxy and sand over all foam and filled gap).

What material would you use to fill the gap? Would silicone work? Would that stick to foam and epoxy stick to the silicome?

10/03/2017, 05:43 PM
Why not more foam? Put both pieces into the tank, then squirt a bead of foam along the seam. Once it's cured, shape as desired. It's pretty common to just build the foam wall right inside the tank in the first place.

I would not use silicone. A huge glob like that would take a looooonggggg time to cure, might not adhere well, and would be hard to blend in to the surroundings without looking like a big wad of snot.

10/04/2017, 09:10 PM
I think I will just use foam. I was trying to avoid it because I put salt over the rest of the foam, soaking the foam to get salt out, epoxy over the dry foam and then sand on the epoxy. I didn't want to do all that to just a strip of foam but I guess I'll just foam and throw sand directly on it to fill the gap.

Also I didn't want to just waste a full can for a strip but I found out cleaning with acetone should preserve the can for future use.

Regarldess, yes I think using more foam is probably the best choice.