Totally Foam - Rock Wall...

[mmittlesteadt]

I'm making a foam rock wall to cover the overflow and return fittings on my 40 gallon breeder, but I only wanted it to be very slight and not to be made of any rock. I will have plenty of rock in the 40G DT as well as my 65 gallon sump in my basement. This "rock" wall is for decorative/camouflage purposes only.

You can read about my build here.

Anyway, for a little background, I am a professional artist specializing in murals and dioramas, mostly for museums and I create all kinds of exhibits utilizing a wide variety of materials. While this is my first serious attempt at reef keeping, I've been making artificial habitats for my freshwater aquariums for over 35 years. I've read every single thread on RC related to artificial rock walls, and I decided to make this for my tank. Below is the making of this wall for anyone interested...

Well, my bulkheads are installed, overflow is siliconed in place and this is the start of my arch wall that will hide my overflow and the return.

Crappy pic of the overflow and bulkheads...

Couple of shots of the layout of the styrofoam. Almost all of this will be carved away, so it looks WAY thicker and bigger than it will end up being. Most of it will be thinner that even the single layer, but I wanted to start with it large and carve ledges and overhangs in the right places. I will also be cutting out a huge chunk for the cave (where it's X'd out on the styro in marker). And of course, one the left, I will cut down the artificial rock wall below the overflow's top so it does not interfere with water flow and no animals will crawl into it.

Very little of this styro will remain. Most of it will end up being carved away. And no, the pipe sticking out will not be there...it is only a placeholder for where the return will come out under the fake rockwork.

The whole thing will be covered in black pond foam after it's carved out.

 

[mmittlesteadt]

Further sculpting...lots more will be removed. This is just basic shaping before the main chunks get siliconed together for the final shaping...

 

[mmittlesteadt]

Now that the basic structure is shaped, I siliconed all the 2" pieces together. I built a platform out of luan that mimics the aquarium's glass walls and the 45 degree overflow glass wall so I can work on it out of the tank and apply pressure without the styro coming apart (and later when I go over it with the black spray pond foam and aragonite).

Having worked with styrofoam (foamular) for museum work as well as freshwater aquariums, the key to getting it to stick together and stay under water (because it wants to float) is to not treat the silicone so much like a glue, but rather an anchor.

You drill holes in the styrofoam and fill the holes with silicone and then also put silicone between the pieces. After it cures the foam cannot separate (or lift off the glass later when glued into the tank) because first of all, silicone adheres VERY well to styrofoam, but also the siliconed filled holes act like plugs that the styrofoam cannot pull out. The key here is also to take a propane torch and melt the styro around the holes so that it becomes extremely hard like a hard plastic.

This is also done when gluing it to the glass walls. The 2" thick pieces here are also "pinned" in place by siliconing fiberglass rods into the pieces. You drill through both pieces, fill the hole with silicone and then drive the rods into the holes (deep enough so you don't expose them by further sculpting and also it gets pinned at the thickest parts of the sculpture.

Anyway, the styrofoam pieces are sitting waiting for the silicone to skin over so they won't move when I go at it later with my drill. At this point it is not necessary to let the silicone cure completely...just enough so the pieces don't move. You'll notice I have my "spade" bits on the work surface. These are ideal sculpting tools as they not only drill various size holes in the styro, but also cut it down to further shape it, and best of all (given I'm making fake dry rock) they do a great job of "tearing" chunks out of the styro. When that part is done, I go over the entire thing with my propane torch and melt the styro even further until it is exactly how I want it.

It still looks thick and chunky, but it will not when I'm done. It will be quite thinned out and much more sculpted further. It's only there to be a "base" for the black pond foam. I will only need to use one can of the pond foam because while the pond foam expands, I will not allow the black pond foam to expand much because as I go over this with it, I am going to dump a lot of aragonite onto it and press it down while it's still sticky and trying to expand. I'm not using the pond foam as much for shape as I am for putting a thick skin of it over my styrofoam. Stay tuned.

 

[mmittlesteadt]

OK...here's the styro after using the spade bits in the drill and melting it for further shaping with the propane torch.

If the foamular wasn't pink and wasn't subject to UV degradation, I'd leave just as is, because I really like how it turned out.

But since it needs to be covered, I did that black pond foam and before it could expand too much, I threw aragonite all over it and then as it started to set up I pressed it into every little hole, crevice and contour I could feel. I just kept going over and over it that way so it is really nothing more than a thinner coat of black foam all over the styro.

 

[mmittlesteadt]

And the artificial rockwall is complete. Just need to silicone it in place.

 

[NanoReefWanabe]

looks great…make sure you silicone the poop out of it…it is going to float right out of there…i would do something to cover the top portion above the return though…it will turn soft and yellow and start fluffing into your tank…

i would do your very best to make are it is completely sealed all the way around to stop stuff from getting behind it and to stop water from working the silicone loose.

 

[mmittlesteadt]

I've kept styro from floating in freshwater tanks. It's not how much you use, but how you use it.

As mentioned in an earlier post, holes get drilled in the back, then the styro surrounding it get melted by a propane torch until it is is hard. You fill the holes with silicone and then out and all around it on the back. It creates plugs made of silicone.

The silicone sticks to the glass and the styro won't pull off because of the silicone plugs. Never had a piece break loose and float up on me (in freshwater), even ones that were far more buoyant and larger than this one. The size is decieving. There is not that much to it and there is far more sand (in weight) on it than there is styrofoam. It is quite heavy for it's size.

The top portion of the entire back wall will not get any light. The glass top of my aquarium will be taped off blocking light in that area. I don't want any light in the back corners of the tank and my LED lights are 24" long and the tank is 36". This is by choice. The top of the wall will also be above the waterline by about 1/2".

 

[Chasmodes]

Looks great! I will be following for sure...

 

[mmittlesteadt]

Here are the finished pics, sans water...

 

[JimKelly12203]

absolutely fascinating. It looks fantastic. Can't wait to see how it looks when you start adding living stuff.

 

[mmittlesteadt]

absolutely fascinating. It looks fantastic. Can't wait to see how it looks when you start adding living stuff.

Thanks. Me neither! The display tank is done and the sump is done. Just a couple of small things to work out with my ATO and RO/DI and it will be filling time!

 

[salty joe]

That's the nicest foam wall I've ever seen. Adds a lot feeling of depth. Very natural looking. Good directions too. I'd bet it will look even better with water due to refraction.

I've used silicone many times as you described. Recently siliconed a PVC pipe hanger to an epoxied wall by squishing the silicone through the holes in the hanger. It's rock solid.

 

[mmittlesteadt]

Thanks! There is a lot less styro than you would think. It's actually pretty thin in most places. Everything is completely covered in black pond foam and aragonite too.

And yes, sometimes when silicone does not adhere as well as you would like, you can force it into a hole so that when it's cured it is one solid mass. The silicone may pull off what you are gluing, but it can't come out of the holes so in a way it acts like those rubber suction cups where the button is forced into the hole of a clip. The suction cup isn't adhered to the clip...it's just stuck in the hole. Same principle.

 

[nomethod101]

Looks incredible!