[boredatwork]

Once I finished my stand I decided I didn't want to do any more DIY ever again. But now I have been looking at all these 3D background projects and I might be changing my mind. The problem is I dont want to impede progress to adding fish (I am currently in the middle of cycling). And even if there wasnt water in the tank I dont think im comfortable gluing the modules to the tank. I know some people have proposed magnets - but I was thinking, wouldn't suction cups work just as well? Im still thinking it through but just thought Id throw it out there.

 

[iceblue]

I think suction cups would not be a good long term solution. With the stryofoam constantly trying to float and pulling on them they would eventually give way.

Personally, I don't like suction cups to hold anthing in place long term. That includes my pumps, heaters, etc....Jmo.

 

[748johnd]

I agree with iceblue. Suction cups don't hold long term. I just purchased a lot of Mag Clips and am in the process of gradually getting rid of all my suction cups. They aren't cheap, but I am sick of dealing with suction cups constantly losing their suction.

 

[boredatwork]

So I was thinking about that too, but more from the point of view of attaching suction cups to styrofoam so the buoyancy of the foam does rip the suction cup out of the styrofoam. I was thinking of trying to weight down the styrofoam with added cement on the inside of the foam module. But then you run the risk of having it weighted down instead of floating up. It might be hard to balance it well enough. The thing is if you rule out the option of gluing the modules on (which for me is the case) it seems like your options are limited.

 

[DMWave45]

Even with cement loaded on the inside of the styro the module would not sink. Someone on here mention that they tried this when making DIY rocks and it still floated with ease.

 

[Eb0la11]

Has anyone ever made up a formula for how much weight it takes to sink 1 cube inch of styrofoam? Would be very handy!

 

[iceblue]

Has anyone ever made up a formula for how much weight it takes to sink 1 cube inch of styrofoam? Would be very handy!

Its also been mentioned to remove the styrofoam with acetate and fill it with a lightweight concrete mix or leave it hollow. I would think that the amount of cement needed to sink the styrofoam would make the use of styrofoam worthless as a medium for making up the bulk of the background.

Mcdaphnia's suggestion in other threads of useing matala mat as a medium for the application of cement seems too me a better idea if you don't want it to float.

 

[spow]

You can make a removeable concrete background. I have made several and its the only way I'd make them now. Here's what I did:
1) Cut a piece of concrete board (DuRock or similar) to the size you need. Consider if you need your background in sections to install in the tank.
2) Silicone styrofoam to the concrete board.
3) Carve the background, hollowing out some of the rocks as best you can to fill with concrete. Cover with a couple layers of concrete in the usual manner outside of the tank. Odds are the background will still float. At this point, poke some holes in the concrete and dissolve the styrofoam slowly using acetone in a spray bottle. Pour concrete in the void to replace the styrofoam. Let it dry overnight then check to see if it's heavy enough to sink. I filled a trash can up with water to test the bouyancy. As mentioned above, you may be suprised at how much styrofoam must be removed. The background will be pretty heavy to pick up but if done correctly it will be lighter in the water. When it seems OK, put on your final layer of concrete.
4) Of course it must soak until pH is stable.
5) To install, just put it in the tank. It will sit on the bottom. You will need to make sure the top is held in place. I pushed some foam weather stripping along the sides to wedge it in place and keep fry from getting behind it. Push sand up against the lower edge.
Here are pictures of two of the sinking backgrounds I made. Some of the "rocks" are almost solid concrete. You might also notice that in the first picture, the "rock" in the upper left is hollow and open to the bottom. This is for the filter intake and heater. In the second picture the "tree" is hollow for the same purpose.

[/quote]