Making Rocks

[Tanyoberu]

We've all seen the 3d backgrounds. We've all been to the aquarium and have seen these elaborate displays. We know fake reef systems are being made all the time. But now, I want to make my own rocks for two reasons. One I'd like the weight to be MUCH lighter than a real rock (if possible) for the annual cleaning processes. And 2, I want total control of the design.

I do not have access to the fiberglass materials reefmakers use. But I can get ahold of the foam. Can I use the foam in that capacity? Or are there other alternatives. The idea is to have ONE large structure that can be moved if ever I need to.

 

[discusfreak2005]

yes, foam would be a great way to solve your dilemma

basically, get foam, silicone, cement and cement pigment

make the shape you want out of foam, use the silicone to help reinforce any branchy or similar parts, then, kind of hollow it out to help reduce bouyancy but keep structure

then coat both the inside and outside of it with a few layers of cement, about 1/4 of an inch worked for me

make sure to add the pigment to the final layer of cement

allow ample drying time between layers

some people coat it with epoxy or a sealer but as long as you allow enough time for it to cure and release any harmful chemicals it will be fine

 

[flagtail]

Fifth and final bloody post in order to vew pics

 

[Princley]

i would not use foam in a tank. fish may eat it not good

 

[discusfreak2005]

as long as any exposed parts are covered with cement teh fish cant get to it

 

[Nic]

what about the lime leaching into the tank?

 

[davo]

i know someone who uses styrofoam - cut and glued to form the desired shape, then burned and coated with sand to obtain the impression of a river bank. it works well, hes had no problems and it looks good.

 

[Recycling Works]

heres a pic of mine, not a very good pic, it looks better live and with water on it its darker, but easily could have made rock or river bed design instead of brick, also heres a couple that inspired me, hope they do the same for you

 

[davo]

that looks awesome. does anyone have a guide to make the rock that real looking??? i cant find a good one on the web. if anyone else has, it would be useful.

 

[BlueNote]

I actually used expandable foam on one of my tanks, just make sure you let it expand to its max, give it at least 7 days before you do the folowing. After it cured and I liked what I saw, I then covered it all in a layer of mortar, this gave it that rock like look, I then finished this off with a layer of tile mortar, same stuff you use for setting tile floors ( I am a contractor so this is how I got the idea ), the tile mortar is very fine, finer then silica sand, and you can then make a nice smooth surface over the regular mortar. I then painted it with a two part epoxy paints from International called Interseal 670 HS. And then let that cure for 2 days, filled the tank, then let it sit, then drains it to get any toxins out that may have been there, then I filled it up again and voila. Perfect 3D background that was light, but had the feel of real rock. I was not trying to make a coral look, but rather a freshwater ridge look.

here is a picture of it.
After Water / Plants and Fish

Before Water