# Silicone on acrylic?DIY 3d background



## eutimio (Aug 22, 2012)

Guys did any of you use silicone on real rock on acrylic for making a 3d background?i read a bunch of posts but none of them say anything about real rock except fmueller but he's got glass.Everyone is either buying the background made from a rubber matterial or theyre making it from styrofoam.I wanna use slate rock or something really thin with some slack on larger pieces to leave space for swimming for the fish .Im looking to glue them with silicone to the back of the tank(i dont know if thats a good idea ).Should i use styrofoam first then attach the rocks onto it?wouldnt it just look weird if not covered all with rock(the foam)?also im looking to cover the overflow and the left side of the tank the same way.if any of you did use silicone with acrylic what kind did you use?Also maybe styrofoam thickness would help too.thanks


----------



## metricliman (Sep 3, 2012)

Here's a few links on real rock backgrounds, but the first one is glass. The second one is acrylic, I believe: http://www.cichlid-forum.com/phpBB/viewtopic.php?t=180796
http://www.cichlid-forum.com/phpBB/viewtopic.php?t=113830


----------



## fusion (Jun 21, 2012)

Could you use some thin styrofoam, attach the rocks, paint the styrofoam with Drylok then attach it to the tank with magnets? Home Depot sell 1" sheets of styrofoam. only thing that would concern me would be the weight of the rocks, dont know if magnets would be strong enough to hold it up.


----------



## DanniGirl (Jan 25, 2007)

I have used silicone with acrylic and it was GE Silicone I for Windows/Doors/Attics. It was used to adhere a 1½" sheet of Styrofoam to the back of a tank and it worked. However, the silicone was used in large quantities. Fans were set up inside the tank to aide with air movement and it still took a week to cure. In my larger acrylic tank, the DIY background is adhered through the use magnets.

I would not suggest the use of silicone to adhere rocks to an acrylic tank. Epoxy-coated, neodymium disk magnets could work. Undoubtedly, a magnet with a pull-force of 85lbs could easily hold up a rock but I would not suggest a magnet of that strength either. A magnet with a pull force of between 18-35 lbs could work. Now the trick would be to get the magnet to adhere to the rock.

Depending on the rock, silicone may not adhere well. Another idea would be the use Gorilla Glue or attach the rock to Styrofoam. Attaching the rock to Styrofoam would be a lot of work, especially if it's the first time working with Styrofoam. If the rocks are angled as described, you would be looking at multiple layers of Styrofoam in order to withstand the weight. Depending on the weight of the rocks, you could be looking at Styrofoam with a minimum thickness of 2" but more likely around 4"-6" for majority of the project. In order to make it look good, rocks should be overlapped to hide the Styrofoam. If not, each rock will have a thin halo around the base. You could use Pond Foam (sculpt before it cures, then touch up after it dries) to hide the halo and give a fluidity to the background but that can be messy as well. Paint does not adhere to Pond Foam that well, so keep that in mind.

Another idea would be the use of epoxy resin, but if you're not familiar with it, then I would not suggest it.

Now, if you just wanted to create a slate background, similiar to the one *oldcat* had created, that would be far easier to achieve.


----------



## eutimio (Aug 22, 2012)

that is wxactly what i was going after-oldcat's idea.He did exactly that.Glued the rocks to the PVC then put it in pieces in the tank.Now he doesnt say how he glued the PVC piece with the slate on it to the back of the tank but i guess glued as well?


----------



## fusion (Jun 21, 2012)

My concern with Gluing directly to the acrylic would be if you ever wanted to change it, im thinking you would have a hard time getting it off.


----------



## DanniGirl (Jan 25, 2007)

eutimio said:


> that is wxactly what i was going after-oldcat's idea.He did exactly that.Glued the rocks to the PVC then put it in pieces in the tank.Now he doesnt say how he glued the PVC piece with the slate on it to the back of the tank but i guess glued as well?


That tank is glass and it looks like the background was siliconed in place. It could be glued as well, I don't know.

Keep in mind that it leaves out the idea of leaving _"some slack on larger pieces to leave space for swimming for the fish" _. *Oldcat's* slate background is tightly overlapped so there are no crevices for the fish to swim between the rocks.

Another idea to keep in mind, if you have something permanently installed in your tank and a fish wedges itself between a crevice, you're going to need to retrieve the fish somehow.


----------



## eutimio (Aug 22, 2012)

you're right overlapped rock looks even better in my opinion without the concern of trapping fish in the back of the rocks somehow or even worse having to deal with a dead one in the back of them.imagine the nightmare.unfortunately I cant find any thread that gives me just that little hope to start with this project.Now i wish i had a glass tank.The possibility of this project on acrylic is gone right?i dont wanna deal with magnets ..imagine i would have to buy a bunch of them and have a hard time gluing them to the rocks.........i guess ill just have to look into the plastic ones or just leave it plain black...


----------



## fusion (Jun 21, 2012)

eutimio said:


> you're right overlapped rock looks even better in my opinion without the concern of trapping fish in the back of the rocks somehow or even worse having to deal with a dead one in the back of them.imagine the nightmare.unfortunately I cant find any thread that gives me just that little hope to start with this project.Now i wish i had a glass tank.The possibility of this project on acrylic is gone right?i dont wanna deal with magnets ..imagine i would have to buy a bunch of them and have a hard time gluing them to the rocks.........i guess ill just have to look into the plastic ones or just leave it plain black...


Why dont you build a styrofoam one? its what im doing, some of the ones in the diy background thread are amazing, i will silicone mine on plus wedge it beneath the acrylic top


----------



## eutimio (Aug 22, 2012)

dont know..it just doesnt look real to me and matching the styrofoam with real rock that im gonna add anyway throughout the tank is a hard task ..


----------



## DanniGirl (Jan 25, 2007)

eutimio said:


> dont know..it just doesnt look real to me and matching the styrofoam with real rock that im gonna add anyway throughout the tank is a hard task ..


You can always paint the rocks to match the background.

There's nothing saying you can't try it. Try a small portion (the side of the overflow) and see how the silicone holds up. Keep the rocks thin but be heavy on the silicone.


----------



## eutimio (Aug 22, 2012)

thats what im gonna do.Thanks for the input.Im on the way to finding some rock!


----------



## DJRansome (Oct 29, 2005)

Don't forget how heavy the rocks are. I knew someone who glued rocks onto the back glass and then could barely move the tank.


----------

