How to fill voids in a DIY waterfall?

[WhistlingBadger]

So, I have built this great-looking waterfall out of blue insulation foam, painted it to look very realistic. Trouble is, it doesn't quite fit perfectly, especially around the pipe manifold going through the bottom, but also where the sides meet the tank walls. I need to fill in 1/2-1/4 inch voids somehow. It needs to be water-tight or very close, and able to endure some pressure.

I was planning to use expanding foam, but I've read that is nearly impossible to remove from glass. I want something I can remove from the glass if and when I tear down the tank in a few years.

Perhaps I can stuff the voids with filter floss then spread silicone over it, or paint it with dryloc...that seems impractical.

Any ideas?

 

[Rocky998]

So, I have built this great-looking waterfall out of blue insulation foam, painted it to look very realistic. Trouble is, it doesn't quite fit perfectly, especially around the pipe manifold going through the bottom, but also where the sides meet the tank walls. I need to fill in 1/2-1/4 inch voids somehow. It needs to be water-tight or very close, and able to endure some pressure.

I was planning to use expanding foam, but I've read that is nearly impossible to remove from glass. I want something I can remove from the glass if and when I tear down the tank in a few years.

Perhaps I can stuff the voids with filter floss then spread silicone over it, or paint it with dryloc...that seems impractical.

Any ideas?

I've seen this stuff used in aquariums before. I think it would be worth a shot!
I know you said no foam... BUT, I've heard it comes off easily (I thought). Or maybe you could somehow put a spacing between the glass and the foam if that makes you feel better? Idk

GREAT STUFF 12 oz. Pond and Stone Insulating Foam Sealant 283064 - The Home Depot

GREAT STUFF Pond and Stone is a polyurethane-based foam sealant designed for use in water features. By expanding to fill gaps and cracks, it works as a water-resistant sealant to help direct the flow of water in waterfall, pond and streambed construction to go where you want it to go, not under...

www.homedepot.com

 

[WhistlingBadger]

Yeah, I thought about that. I've used it on ponds before, and it's great stuff. (Hey, they should name it that!) But it is extremely adhesive, and there seems to be no way to remove it from glass once it cures. Since the whole design depends on my fake rocks sitting snugly against the glass, putting a space there wouldn't work.

I think I'll just glue my pieces into place, get them as close as I can, then fill the voids with little wedges of blue foam and silicone.

Certainty of a huge mess; small chance of success.