Spray foam rock work

Me and the wife have really been kicking around the idea of filling the tank up again. I have been thinking of making the background and pump holders out of spray foam. Anyone on here ever try any of this and what type of products they suggest? Maybe even some good links to tank builds? Thinking of trying to incorporate a eel house into it the back and would be fish only, I swear. I am wondering a topical roll on product would seal the foam good enough like they use in showers. The stuff I was thinking should be good enough in my mind because it is designed for exterior use as well. Algae would grow on there and u would never know the difference at least I think. Anyone has any ideas or tips let me know. Really have not researched it at all but back in the day I am pretty sure people were doing this.

Hey, good to hear from you. Paul Whitby will be at the April swap giving a talk on aquascaping. I was reading about aquascaping using polyurethane spray foam and standard GREAT STUFF is used very successfully. Coralline algae attaches very quickly but it can also be painted with non-toxic marine epoxy paint.Charles Delbeek & Julian Sprung Reef Aquarium Vol 3 warn against using latex foam because it is open cell and might break down over time.GREAT STUFF is closed cell.

Yeah open cell would deffinetly be a horrible product. Water doesn't do well with it. I was thinking a closed cell and possibly sheets of foam. Maybe like a 4 piece deal so we could make out of tank and drop them in instead of foaming the actual tank. Very good input thanks for the reply

He suggests 1/4" sheets of acrylic that can be tacked onto the sides of the tank with a small amount of silicone sealant. Spray the foam into the acrylic. You can press rocks, gravel, etc into the unset foam to create texture. Once cured, you can spray again to create more texture and after it is cured, cut with a knife to create caves etc.

Oh, I have rocks in a bucket of used saltwater from HSC, sand in the sump at HSC, and my neighbor working on my stand. My goal is to have a functioning tank by the swap.

I have no tips on foam but had to post and say I'm thrilled to see you guys are considering getting back "in".

Eels are escape artists aren't they? Would you have to close off the top?

I have two cans of pond foam you can have for free if you want them... I was going to do this and never did. They are just taking up space in the garage at the moment.

Cd since u have these products u must have researched. Do I have to use pond foam or can I just use some stuff I can get in town? Really hoping to be able to use a combo of sheets and spray. Also been kicking around the idea of after waterproof about skinning it in Crete and adding some sand for more of a natural texture.

Well this information is just what I READ, not personally experienced accounts...

First off, the regular great stuff foam is fine to use. However it is less dense and doesn't have as good of a resistance to the intensities of light we use in the hobby. Also the black pond foam is easier to cover and look good so the yellow doesn't stick out so much if there is a little damage over time... The pond foam is also meant to be used in water so it holds up to being submerged much better as well. Remember to spray in the foam, let it form a tough top layer, then you can press it down or form it how you want it without breaking the nice seal layer of the foam.

Regarding the backing, I would use eggcrate, not acrylic. The eggcrate allows for easy attachment of rocks with zip ties. This allows you to use dry rock for the majority of the wall and "fill in the gaps" with the pond foam. It gives you a better wall as it is functional as well as good looking. The foam will do nothing for biological filtration so the rock will give you that. Also if you have ever tried to glue acrylic to glass with regular silicone, you will know it doesn't really stick well. The eggcrate will give a rougher surface to attach it to the back wall. It also lets you zip tie in PVC to make nice tunnels for the fish who like hiding spots as well as cut out a spot to hide your powerheads if you use them...

The epoxy must be used no matter what foam you use. Basically mix it up and brush it onto the foam. Sprinkle sand or crushed coral into the epoxy and it will make the foam look like it is supposed to be there. It will also let the corraline grow better on the rougher surface.

Concrete and foam I wouldn't do. The weight of the concrete could crush the foam and the chemicals in the concrete may mess up the foam's finish.

If you want the cans, they are yours for free. I will be back up in the area when the lakes return to "soft water" status... Otherwise if you know someone heading this way I can send them up to you that way. I think Raul on RRVR gets over there occasionally for work and may be able to take them to you as well...

I have used the Black Great Stuff in my pond and in my reef.
TIPS
DO NOT try to spray foam an island or rocks in the water. The foam puts out horrible oil slicks.
This stuff really floats. I foamed in a cool tower of coral fragments to one corner of my tank. It slowly peeled away from the wall. It does not stick forever. Pretty easy to peel off. I would hesitate using it to glue something perpendicular to the glass. Small amounts make a good substrate for putting in rocks etc. on the bottom. I had a pistol shrimp and if not for the foamed in rocks the whole structure would have collapsed.
I like the black as it looks more like shadows. The regular stuff can turn yellow under lights, or sunshine.
I will continue to use the black Great stuff, on my pond and in my new tanks.

Thank u very much for the tips and I will let ya know if I need the foam or not. Depends really how fast I get moving on it