Foam Background and pH

[ryanoh]

I'm in the early stages of planning a DIY styrofoam background. Right now the plan is get the foam then cut the foam, but I'm not sure what to do from there. The most common thing I've found online is Readymix Quickrete, then epoxy resin. Some other forums have talked about just putting the cured cement directly in the tank without the epoxy coating, but I know this will drive the pH up.

Is it possible to neutralize the pH by adding wood to lower it or will the cement raise it more than wood can drop it?

If this isn't possible, can the concrete step be skipped and I just paint my foam then resin over it? I'm thinking mainly about weight here because if there's no need for concrete I'd rather not have the extra pounds in my tank.

I'm planning on fixing it to the back with industrial magnets rather than siliconing it to my tank so that if I ever change my mind, have a component behind it break, or just generally need to remove it I can.

Should I add the concrete to weight it down or do you think magnets coming from the back would be strong enough to keep it from floating away?

I'll probably glue to foam blocks together today and start carving tomorrow, but I also might post some sketches of my idea in this thread later tonight.

 

[ryanoh]

Also, when glueing the foam sheets together, does it matter what you use? I have some Silicone II, which I think is toxic until all the chemicals are leached out, but would it matter since it would be encased in concrete or epoxy?

 

[aakaakaak]

I haven't done anything like this before, but it would make sense to me to make everything fish safe, including the epoxy. What happens if you get a crack in the resin coating and the epoxy chemicals leech out?

 

[ryanoh]

Yeah, you're right. For the record, Silicone II is not for fish, but Silicone I is fine.

About the pH question I had, this video kind of answers my question. Of course, I'm going to be monitoring the pH of my tank very closely once I put the background in, but I think I'm going to skip doing the resin coat. The less money I can spend on this project the better, and the less steps I have that I can mess up the better as well.

 

[ryanoh]

Well, its underway. I glued most of the styrofoam together tonight but ran out of silicone part of the way through. I need to go pick up another tube tomorrow, glue it, let it dry, then I'll start carving the surface Monday.

I feel like this was the most challenging part since I had to leave enough room for all of my equipment, and it was a lot of measure and planning.

 

[aakaakaak]

IMO all the little arts and crafts projects we do are a big part of what makes fish keeping fun.

I don't think I'll be adding a foam and concrete background to my tank (even though I think it's cool as hell) but I like the projects.

 

[ryanoh]

As an art student who almost emphasized in sculpture, I whole heartedly agree. Much of the enjoyment of this hobby for me comes from the things I make.

 

[riseabovethesun]

Make sure your background that glues to the tank isn't too thick. I spent about a week working on mine, perfecting it, glued it in and because my main foam piece was far too thick it was able to pull off.

It was the only foam we could find around town though, you may have found some nicer thin stuff.

But DIY backgrounds rock! I wish mine would have worked, maybe another time. Can't wait to see yours :]

 

[ryanoh]

I ended up glueing a few thinner sheet together to make it thick enough to carve on. It's a lot thicker now than it's going to be once I cut a bunch of foam off of it. I'm not sure what you mean that yours was too thick though?

Here's what I've got so far. All the functional pieces are cut out, so now all that's left to do is make it look how I want.

The space on the left is where my filter, heater, and powerhead will go with water coming in through the grate, the notches and space on the bottom are where my jet system will go, the middle is for my bubble rod and the spaces going up from it are where the bubbles will be able to get out of holes I'm going to poke later.

I'm thinking about doing something crazy when get down to sculpting, but I need to do some drawings first and make sure it'll work. I'll put up a few drawings and let you guys vote.

 

[aakaakaak]

I totally have no clue how it's going to look when it's done. I'm horrible at imagining someone else's artistic vision until it's at fruition.

Edit: My "big project" is cutting out the right sized pieces of wrapping paper for my 10 and 29 gal. (So I finally have backs.)

 

[ryanoh]

When I went to cutting on the front a lot of the pieces fell off because I guess I didn't glue them that well. You've got me really nervous that its going to fall about when I put it in the tank. : /
I hope the cement really, really, REALLY holds it together well because I'm pretty anxious about it right now...
I'll probably start with the cement Wednesday night. I have a bit more carving to do right now, but I'm almost finished.

 

[riseabovethesun]

The only downfall to mine was that it was too thick of foam. I bought a piece of foam for the back, then bought another piece to carve out rock shapes. I put toothpicks in the rock shapes and silicone, and stuck them to the main foam piece. Then let that dry for a few. I bought a suggested cement for the project, but would have picked a different one had I know it had tons of little rock pieces in it, so it made it difficult to get the cement with the rock chunks. Eventually after 3-4 coats it was good, all dried. Siliconed it to the back of the tank, let it dry, then added water it was fine for about 2 hours, left to go get some stuff and came home to it haven't detached from the back of the tank floating on the top.

My main foam piece was about 3" thick or so, way too thick. This is what it looked like before it detached:

I wouldn't worry, I think yours should be fine.

 

[ryanoh]

Whoah, that looks really good. What kind of cement was it? I've got a big, red bag of quick-drying Quikrete.

Also, the thickest piece of foam, which is really four sheets glued together, is 3.5 inches. That's only one part though, not all the way through.

 

[riseabovethesun]

Mine was Quickrete as well. The kind that said ready in minutes, or something. It was the cement dust stuff with tiny pebbles in it, which sifting out the rocks and putting the cement on was fine, but if there were rocks and they got bumped that had been plastered on, they'd fall off and take a little chunk with them. And I believe the bag was either brown or yellow.

But while it sat in the water nothing floated off or had any issues.

I really liked that background, a bummer it didn't work out. Now it's just sitting on my balcony, sunbathing.

 

[aakaakaak]

If it were me I'd try and use that magnet thing you were talking about or suction cups, so it could come off easily if you need to clean it.

 

[riseabovethesun]

If it were me I'd try and use that magnet thing you were talking about or suction cups, so it could come off easily if you need to clean it.

That's a pretty good idea, I'd shoot for that. Just make sure it sticks to the glass enough or the substrate is high enough so that the fish don't go behind it or on the sides of it :0

You can tell in that photo I accidentally had glued mine on crooked, so the fish were trying to sit under it since the substrate wasn't in. But those were fish that were going back to the LFS and needed a temporary home. So glue yours on right or however you do it! LOL I was just giving mine some character..

 

[ryanoh]

I think I'm going to use magnets for sure so that I can get a right seal. I have it in the tank now just to make sure it will fit, and as long as the back edges stay tight they shouldn't be able to get behind it. I need to go on a hunt for magnets here in the next few days...

Riseaboethesun, I posted some updates and question in the 'my tank' thread in my signature, so if you wanted to go look at that and give me your opinion, that'd be awesome.

 

[ryanoh]

I'm at a crossroads here with this.

I need to leave room behind the background for my filter, but I also need to make enough contact with the back for fish to not get behind it, and I'd really rather not silicon anything to my tank. I was thinking about making something that looked roughly like this (from the top)

l___l___l

The three 'legs' would be up against the back of the tank, and the flat part would be facing out. My equipment would go on the right side, and I'm not sure what to do with the left side. Would this work, and does anyone have any idea what to build it out of?

 

[aakaakaak]

1. Put everything in place except the foam.
2. Put a plastic sheeting over the filter and everything else that will be hung on the tank backing behind the background.
3. lean your tank over so the back is now the bottom.
4. use spray-on foam on the plastic sheeting to make a mold.
5. Let it dry like that.
6. remove plastic sheeting and treat as regular foam.
7. continue as normal with the concrete plan

 

[ryanoh]

As great of an idea as that is, I think I'm going to cut my losses and go with a slate background like this one. Me and my girlfriend (especially her) were getting tired of the sytrofoam all over the place, and it was going to be too much to get it to stay in the tank without glueing it. Thanks for the support though.