# Most Dense, Thin, Flat Rock?



## WaWaZat (Dec 27, 2007)

I am planning a shopping trip to my local garden center in search of an approx 6" x 18" flat rock that is under an inch thick. I will be using this rock to keep a 3 foot surfboard submerged by wrapping some fishing line around the rock which will be attached to the board. The rock should be thin enough to keep completely covered under my planned sand substrate. So the key is that the rock be thin, flat & heavy. What aquarium safe rock might be best for this task? Would slate do it or might I find something better or heavier?


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## KiDD (Aug 20, 2010)

Your going to have a hard time sinking a surf board....


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## PfunMo (Jul 30, 2009)

While Kidd is right about sinking it, I should think it possible on a small board. Rather than landscape rocks, I might go with floor tile. It is cut down to 1/2-3/4 inch thick and not totally too expensive. Are you wanting to preserve the board and want to avoid damage to it? If not cutting the bottom out and adding concrete will cut the bouyancy as well as add weight. Otherwise most any rocks will be safe if you go the landscape route. I would avoid the ones with muddy looking spots that might bleed out more in the water. Not usually a problem.


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## Number6 (Mar 13, 2003)

*WaWaZat*
most folks create a fake version of such items for an aquarium...


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## Camaro95 (Nov 11, 2010)

Is that board going to be a ledge kind of suspended in the middle of the tank?


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## Pali (Dec 22, 2009)

I also belive this is gonna be a hard task to compleate, but I would go looking for some marble slate. It's pretty dence and heavy material, tank safe and easy to come by.

It's mostlikely not the cheapest option in a landscape shop, but atleast here it's pretty easy to find a old marble tables or stuff like that people no longer use. I figure color isn't gonna matter as you where gonna cover it with sand.


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## PfunMo (Jul 30, 2009)

Actually for the small difference in density versus the large difference in cutting and working, I feel the softer, easy to cut stuff would be my choice. But then neither would I be putting the board in my tank!!!


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## WaWaZat (Dec 27, 2007)

The board will be angled to its side... like a very steep carve on a wave. I plan to put a couple screws into the back near one of the side edges so that I can secure fishing line to them, then wrap the line around the rock. This will anchor that side of the board near the bottom of the tank. I plan to wedge the opposite side edge of the board into the upper back corner of the tank.... where the back glass meets the top (acrylic tank). The only prob with the screw idea is that these boards are basically a wood laminate over a foam core so I may have to use some surfboard repair cement, or something, in the holes to help hold the screws... and maybe some silicone around the screws to keep water out of the core.

The positioning of the board should provide a fish hiding area. Since I'm going for a clean, simple beach scene, there won't be much more than beach sand as a substrate, maybe a piece of driftwood and a few plants that look like switchgrass... or some sort of plants you might find growing on a beach. On the other end of the tank, I was thinking of possibly putting some tall bamboo or something that might resemble a palm tree (or that look like palm tree trunks which run from bottom to top to give the impression that trees extend out of the top of the tank). But tough call on what to use since I will be stocking with Oscars, maybe a Clown Knife and other big guys.

Here are a couple pix of the approximate position I'm thinking for the board...


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## fmueller (Jan 11, 2004)

WaWaZat said:


> The only prob with the screw idea is that these boards are basically a wood laminate over a foam core so I may have to use some surfboard repair cement, or something, in the holes to help hold the screws... and maybe some silicone around the screws to keep water out of the core.


As far as my extremely limited knowledge of surfboards goes, I would imagine the core is made out of Styrofoam. If that's true, it makes no difference if water reaches the core, because Styrofoam is aquarium safe and will not soak up any water.

On the off chance that the core is made from a different foam material that does soak up water, I would consider that a huge plus for your purposes, because that could really help with making the board sink.

But I was led to believe that a surfboard's whole purpose of being is not to sink, and to support the weight of a person standing on top of it. So... :?


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## WaWaZat (Dec 27, 2007)

fmueller said:


> But I was led to believe that a surfboard's whole purpose of being is not to sink, and to support the weight of a person standing on top of it. So... :?


Correct! Hence the plan to keep it submerged.

Good info on the foam. This board has a Polyvinyl Foam Core. A quick google search reveals this; http://www.boatdesign.net/articles/foam ... /index.htm

The only prob I might have with the foam is trying to get screws to anchor solidly enough to hold my intended fishing line tethers.


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## PfunMo (Jul 30, 2009)

Any chance of putting something like bamboo on the exposed surface(top) of the board so that the line could be run completely through the foam and attached securely to the bamboo? Got any old surf shoes you want to use for this?


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## PfunMo (Jul 30, 2009)

Added thought- I went looking for cheap plastic plants and found one that worked for me better than the fish shop types. Michael's had a very large group of plastic greenery very cheap. I tore it down and rebuilt it as straight columns of grass. You might want to take a look as you seem to be the inventive DIY sort. I was able to get a tub full of grass for very little. 









I drilled holes in a 2X4 and sett the bases in concrete. I normally bury the concrete in the sand but at least now when the fish take the plants for a ride they settle back to the bottom at the end of the ride.


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## fmueller (Jan 11, 2004)

PfunMo said:


> I normally bury the concrete in the sand but at least now when the fish take the plants for a ride they settle back to the bottom at the end of the ride.


For plastic plants the concrete sounds like a good idea, but Plant Anchors will do exactly the same job with life plants. Just a thought.


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## PfunMo (Jul 30, 2009)

The concrete also works to bond the larger groups of stems together. I'm sure lead plant anchors would work as well but I started out making a large random planted area so I poured a thin bed of concrete and stuck the plant stem through. Since I was pouring those I poured the rest with the spare concrete I had mixed. I have all the larger groups in tanks already and didn't want to pull them out for pictures. Pure lack of motivation!!!


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## kriskm (Dec 1, 2009)

How about using something like Gorilla Glue to glue the rock to the back of the surfboard? The rock would show, but you could pick something from the landscape shop that was big, chunky, and looked cool. You'd only see it from the side, not the front. Just a thought.


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## Teggy (Nov 5, 2010)

I wanted to jump in here and say that isn't a surfboard, but a wakeboard instead. A wakeboard has virtually no buoyancy and usually sink on their own. Though that one looks like a real nice one, I'm mostly familiar with wooden ones. I will still guess its buoyancy is practically nil. And if that's true, then you can probably just epoxy it in a bit where you can't see, say on the top back, and the bottom, directly to the bottom of the tank. I would use the most epoxy on the bottom since you can just cover it in substrate, and also get that cool "surfboard in the sand" look.


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## WaWaZat (Dec 27, 2007)

Teggy said:


> I wanted to jump in here and say that isn't a surfboard, but a wakeboard instead. A wakeboard has virtually no buoyancy and usually sink on their own. Though that one looks like a real nice one, I'm mostly familiar with wooden ones. I will still guess its buoyancy is practically nil. And if it is, then you can probably just epoxy it in a bit where you can't see, say on the top back, and the bottom, directly to the bottom of the tank. I would use the most epoxy on the bottom since you can just cover it in substrate, and also get that cool "surfboard in the sand" look.


No, it's actually a skimboard and it's buoyant. It's basically a piece of foam covered in gelcoat. I am planning on filling the tank soon to see just how much resistance it takes to hold it down.

But I like your idea! I guess I'm just afraid to epoxy to my expensive acrylic tank. How permanent would that be? And what kind of epoxy would hold & be non-toxic?


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## Teggy (Nov 5, 2010)

Lol thank you, SKIMboard. I swear that is what I meant lmao. The one you throw and jump onto at the beach haha. It looked like it would be more buoyant than the ones I've seen so that doesn't surprise me. As far as the silocone on the tank, I've usually been able to pull it off with enough patience and "finger strength" lol. Perhaps stick a glob to an unseen part of the tank and see what happens when it dries, as far as how hard a time you have getting it off, and if it leaves any damage. My guess though is you would be fine. One nice thing about what your doing is you can attach the bottom to the bottom of the tank, and the back to the back. Both spots will be out of view for the most part if you decide something else later on.

Edit: I said epoxy before, I meant to say silicone lmao. Sorry bout that was using the stuff earlier so I guess it was in my head..


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## WaWaZat (Dec 27, 2007)

Teggy said:


> Lol thank you, SKIMboard. I swear that is what I meant lmao. The one you throw and jump onto at the beach haha. It looked like it would be more buoyant than the ones I've seen so that doesn't surprise me. As far as the silocone on the tank, I've usually been able to pull it off with enough patience and "finger strength" lol. Perhaps stick a glob to an unseen part of the tank and see what happens when it dries, as far as how hard a time you have getting it off, and if it leaves any damage. My guess though is you would be fine. One nice thing about what your doing is you can attach the bottom to the bottom of the tank, and the back to the back. Both spots will be out of view for the most part if you decide something else later on.
> 
> Edit: I said epoxy before, I meant to say silicone lmao. Sorry bout that was using the stuff earlier so I guess it was in my head..


Oh, so any particular kind of silicon that would work best?

Yes... the kind you throw on an inch or 2 of wave break, jump on & ride! This isn't one of those cheap wooden skimboard. This is actually a decent $100 one!


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## Teggy (Nov 5, 2010)

> This isn't one of those cheap wooden skimboard. This is actually a decent $100 one!


Ya it looks like it. It would look very sweet it in the tank. I'm already jealous of what it will look like.


> Oh, so any particular kind of silicon that would work best?


GE Silicone I is what you wanna use, it's sure to be safe for you fish.


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## JimmyJam101 (Dec 6, 2010)

If I am not mistaken, silicone does not stick well to acrylic. Since you are only really showing the top side of the board, why don't you break out some power tools and basically hollow out most of the foam and then fill the hollow space with a mix of fine gravel and epoxy? it would take a good amount of epoxy, but I would think that would do a good job of holding the board down. And your piece is removable when you change your mind later.


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## WaWaZat (Dec 27, 2007)

JimmyJam101 said:


> If I am not mistaken, silicone does not stick well to acrylic. Since you are only really showing the top side of the board, why don't you break out some power tools and basically hollow out most of the foam and then fill the hollow space with a mix of fine gravel and epoxy? it would take a good amount of epoxy, but I would think that would do a good job of holding the board down. And your piece is removable when you change your mind later.


I think opening up the board would be a can of worms. They only thing covering the foam is gelcoat. I'd be afraid it would hold up to the hollowing.

Hmmm... haven't gotten to it yet but will soon. Anyone know how I can find out if silicon will hold and if not, what similar product might?


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## JimmyJam101 (Dec 6, 2010)

I meant to remove only as much foam as you can without compromising the strructure and then replacing the empty area with something less buoyant and more dense. I certainly wouldn't try to take all the foam out, gel coat is not much more than paint.


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## WaWaZat (Dec 27, 2007)

JimmyJam101 said:


> I meant to remove only as much foam as you can without compromising the strructure and then replacing the empty area with something less buoyant and more dense. I certainly wouldn't try to take all the foam out, gel coat is not much more than paint.


I think I'd rather figure out how to secure the board as is. I'm gong to fill the tank soon and stick the board in to see how much buoyancy I'm dealing with.

I'm really hoping to get away with siliconing. I believe guys with homemade sump systems, for instance, silicon acrylic partitions, etc.


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## JimmyJam101 (Dec 6, 2010)

I'll cross my fingers for you. I am not sure if it will stick or not, it was something I read on a thread here where someone was building like a 1200 gal tank.

Please let us know how it turns out.


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## WaWaZat (Dec 27, 2007)

Progress for submerging the skimboard has been updated here; http://www.cichlid-forum.com/phpBB/viewtopic.php?p=1560925&highlight=#1560925


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