# DIY foam rocks?



## Steve C (Oct 9, 2011)

Been working on my DIY foam background for my 55g for the past few weeks and had a thought tonight. Has anyone ever made they're own DIY foam rocks to match their background?

The thought crossed my mind tonight because I am thinking if I made my own rocks then I could make them the exact size and shape I wanted, and coating them with Drylok would make them match my background I am building perfectly. So I'm wondering if anyone has tried doing it or not and if there would be any pros/cons? I used the "search" to see if it had been talked about before and really didn't find much at all about making your own rocks.


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## 13razorbackfan (Sep 28, 2011)

I have made my own live rock for a reef tank using concrete and oyster shell but never out of foam. How would you get it to stay on the bottom?


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## Steve C (Oct 9, 2011)

One of two ways crossed my mind. One would be to silicone it to the bottom of the tank just like the background will be siliconed. But the only downside of that would be I couldn't rearrange the aquascape so I'd have to be sure of where I wanted everything.

Or the other would be to mount it to some flat slate rock on the bottom that could be covered by the sand so you would only see the foam rock. I think that would be the way which would be more user friendly because it would give me the means to redo the aquascape if I wanted. But I'd just have to find a way to mount it to the flat/slate type rock because I know silicone does not adhere to rock too well.


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## PfunMo (Jul 30, 2009)

Have you considered hypertufa man-made rocks? Being a concrete product, it does cover the sinking problem but it does take some time to get around the leaching if it is a problem in your water.


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## Steve C (Oct 9, 2011)

Not really familiar with that but I will do some looking into it. Since I'm setting this up as a new tank I will have some time to cycle and get it ready before I even start to think about adding fish, so waiting to leech out isn't really too big a problem for me. I'll do some checking into that and see what I find, thanks for the suggestion.


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## 13razorbackfan (Sep 28, 2011)

PfunMo said:


> Have you considered hypertufa man-made rocks? Being a concrete product, it does cover the sinking problem but it does take some time to get around the leaching if it is a problem in your water.


Yep...I had to let all my concrete rock I made sit in a small swimming pool in a spare bedroom for about a month. Changing water here and there. Cool think about concrete is you can buy dye in just about any color you want and you can shape the rock creating holes all over the place.


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## PfunMo (Jul 30, 2009)

Hypertufa is a way to make semi-light concrete for things like flowerpots and yard decor. Adapt the mix to fit the tank situation. Rather than use peat, something like styrofoam balls can be used in water.


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## 13razorbackfan (Sep 28, 2011)

PfunMo said:


> Hypertufa is a way to make semi-light concrete for things like flowerpots and yard decor. Adapt the mix to fit the tank situation. Rather than use peat, something like styrofoam balls can be used in water.


Can it be dye'd?


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## PfunMo (Jul 30, 2009)

Yes, it should take dyes much like concrete. It is really just a poor grade of concrete. Rather than using cement, sand, and gravel to make really hard (and heavy) concrete, the mix uses lighter things. Rather than gravel for the chunks, peat is often used. Perlite is also used but lots of things like sawdust, wood chips, and floor sweepings can be used. Not the sort of thing you would want to build a street out of but plenty strong enough for a lightweight flowerpot or man-made rocks. The texture is different than standard concrete as it depends on what you used. For old weathered looking flowerpots, you can brush the outside and make a pitted, beat up old pot. Something that looks like it was used in Greek times when pots were carved from tufa stone.
Hypertufa flower tray


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## 13razorbackfan (Sep 28, 2011)

PfunMo said:


> Yes, it should take dyes much like concrete. It is really just a poor grade of concrete. Rather than using cement, sand, and gravel to make really hard (and heavy) concrete, the mix uses lighter things. Rather than gravel for the chunks, peat is often used. Perlite is also used but lots of things like sawdust, wood chips, and floor sweepings can be used. Not the sort of thing you would want to build a street out of but plenty strong enough for a lightweight flowerpot or man-made rocks. The texture is different than standard concrete as it depends on what you used. For old weathered looking flowerpots, you can brush the outside and make a pitted, beat up old pot. Something that looks like it was used in Greek times when pots were carved from tufa stone.
> Hypertufa flower tray


I think I am going to play with it some and see if I can make some large holey rock. I should be able to smooth it as it dries right?


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## PfunMo (Jul 30, 2009)

Yes, If you can get it at the right time, it smooths pretty easy. I have never worked it trying to get smooth but as I've pulled it out of molds and worked with it when it is a little bit wet still, it does slide around in your hands and leave smooth spots. My main complaint with rocks made from regular concrete mix is that it is too smooth to fit my thoughts of rock texture. I've never tried it for tank rocks as there are so many to choose from around where I have been. I should warn you that adding stuff like perlite or sawdust does make the mix much less strong. Depends a lot on what and how much of each you are using. It will take some playing with the mix to get it to do what you want but for getting rock caves and background it has always seemed like a place to start. At least you know it won't float up! Keep in mind that it takes longer than normal concrete to set. The chemical reaction is thrown all out of order when you use a wierd mix of stuff.


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## Steve C (Oct 9, 2011)

PfunMo thank you for suggesting that stuff because I think once I get my BG and stand done I am pretty sure I am going to give it a go with making my own rocks out of some of that stuff there. Because the color in the picture is VERY close to the color of my BG I am building so that would be a great match.


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## PfunMo (Jul 30, 2009)

I've not tried it so I can't say what it will do but it has been in my mind for quite a while. I got started building pots and it was fun to work different shapes. Good luck.


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## griffk (Apr 10, 2011)

I know everyone does not have access to a ceramic kiln and clay, etc, but I made my own stones, from clay, and fired them with a lead free glaze for my 165 gallon, and my 75 gallon. I also made stumps with roots, as well as caves and large rock formations. They leach nothing because they are fired in a lead free, food safe glaze so they are completely safe for my fish, plus you can use basically any color you want. I have one tank with an off white and gray, and the other a mixture of browns. They are slick and easy to clean, you can soak them in bleach water, when you need to remove algae and due to the glaze they will not absorb any of the chemicals used to clean them. I could post some pics if you like.


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## stevenp (Oct 13, 2011)

ya plz post sum pics, ideas on aquascapin is always welcome cheers :thumb:


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## PfunMo (Jul 30, 2009)

We each have different things that we like for decor but for me the smooth shiny item would not look natural. Nature is rarely smooth as ceramic.

The worry about chemicals from bleach getting into the decor is pretty much myth. Since anything that soaks in will also dry out, the bleach can't be expected to stay in the items we soak if we let them dry totally. Since the chlorine is naturally found as a gas, it will not stay in the liquid state but turn to gas and blow away when exposed to air. The worries about bleach are often more myth than fact.


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