making rock wall

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125g

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Nov 17, 2009
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81
Location
Tacoma Wa
ive seen people use egg crate(i think thats what its called) spray foam on in and make fake walls with it what is this foam called and can you just sprinkle sand and crushed coral on it? whats the best way to do this and are there any examples?
 
I recently made a rockwall using the method you described.

I used egg crate as the 'skeleton' for the rockwall and zip ties to secure dryrock to the egg crate. Once I had the dryrock secured to the rockwall I used the spray foam. There are a few different kinds available, but from reading several posts I decided to use the spray on "pond" foam, which I found at Lowes in the garden area (there is a row for pond supplies). I don't remember the brand name of the pond foam, but you can call or check online to see if they have it in stock. When I got mine, I had to check 2 or 3 stores before I found 1 that had it in stock. I believe for my rockwall (roughly 30" x 24") I used 3 cans of the foam. The other kinds of spray foam are used for insulation purposes, like sealing window casings, etc. I think that is called "Great Stuff", however I read that that kind of foam can break down over time from UV exposure, which we get from our lighting.

For adding the sand or crushed coral, you'll want to use a slow drying 2-part epoxy. I got the 2-part epoxy at Hobbytown USA. I think I used 3 2-part kits for my rockwall. I believe I used the 10 or 15 minute epoxy.

I strongly encourage you to use latex gloves when working with both the spray foam & epoxy, as both can be messy to work with.

There are several threads on RC detailing the foam rockwall process.

You can check out how my rockwall looks here, although I didn't document the build process of the rockwall (wish I did): http://www.reeffrontiers.com/forums/showthread.php?t=48818

If I did it all over again, I would use more dryrock on my rockwall. When I was building it, it seemed that the eggcrate wouldn't be strong enough to support the weight. But after adding the spray foam, the entire wall becomes very solid.

I had a lot of fun designing & buliding the rockwall. I'd certainly do it again next chance I get!

My tank has been set up since Oct, 2009 which isn't very long, but so far the rockwall is working out perfectly.

HTH & good luck!

Rob
 
Sorry didn't mean to be rude just at work and have limited time. Figured you'd get a great response like the one by roblou.
 
I checked and it's actually 30 minute "Slow-Cure" 2-part epoxy I used.

hth,

Rob
 
Eggcrate, lots of dry rock, zip ties, great stuff foam in a can, I used the red can but most recomend the great stuff for ponds. Slow cure (30-60 minute) epoxy and sand.
Here's the one I made for my 20L but in the end decided not to use it.
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I like it..
The only thing I learned is about 10 mins after your FOAM your stuff go back and push the foam back in to "deflate:" the air out.....
Nice job!
 
I have a question.
Why do people use the great stuff to cover perfectly good rock and then cote the whole thing with epoxy? Doesn’t this defeat the purpose of the rock in the tank? Aren’t you sealing all the pours and preventing the rock from doing what its job is in the tank?
 
Well, IME I only wanted to use enough foam to fill in the spaces between the rocks, making a bunch of single rocks into a solid "wall", not to cover any of the rock, just fill the gaps.
 
I have read alot about this. Do NOT use great stuff Use Becketts Black Pond Foam.I got it at Lowe's. Use as much rock as you can get on the eggcrate. Then I stood my wall up braced it then squirted the foam on to a 2" wide stick an smeared it on from the back side. Once the foam dried I took a dremle tool to the face of the wall an exposed as much of the rock as I could.
West marine in Fife sells a 2 part epoxy with a 45 min work time 8oz for under $20.
 
becketts is what I use and I just bought one of the great stuff pond foam in a black can that stated used for ponds to secure and block water etc. I will see how this stuff works I am using for a whole other purpose though not for a rock wall but for a baffle in a 50 VAT..... to make my water level never change for my skimmer. unless the return pump is off.
 
I made mine with full blown aragocrete. I lined the back of the tank with pergo underlayment, used some PVC scraps to make a few caves and frag mounts and then used some great stuff foam to give it even more character.
Afterward I made my aragocrete with a 40 pound sack of med sized sand, 5lbs of white cement (grey would be just fine) and two boxes of rock salt to make it more porous.
 
I'm thinking about making a rock wall and have a couple of questions. The rock I'm going to use a few pieces are kinda big, once the foam is dry will it hold the rock to the eggcrate? Does purple coralline grow on the foam?
 
As much as possible, I used zip ties to hold the rock to the eggcrate. Smaller pieces of rock I just let the foam hold it in. The foam does harden and become quite rigid, so holding smaller pieces doesn't seem like a problem. But, depending on how large, gravity over time might be enough to lessen the strength of the foam.

In regards to coralline growing on the foam, I would assume it would, however I personally covered all the foam with epoxy and then while the epoxy was still wet sprinkled sand over. The end result for me was really no foam visible. Also, there is some speculation that UV rays over time may breakdown the foam, which is why many people will do the epoxy/sand coating (along that note, the concensus seems to be to use pond foam and not the other spray foam designed to insulate cracks. pond foam is black, the other stuff is yellow I think).

HTH & good luck!

Rob
 
I already bought 2 can of the breckets black foam. Good point about the foam breaking down and using the epoxy as a sealer. Thanks
 
heres mine after 4 months being set up and scarping coraline from the 125's sump
YES coraline grows on the foam
AND it actually is a good house for pods
We have thousands in our foam
you poke it wit something and pods scatter all over
very cool.
april3001-1.jpg
 

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