extruded polystyrene

[lionshare]

Quick question i have made my 3d background and coated it with a few layers of quickcete. I have been following threads on this site for ideas.

I have made mine fully removable and dont plan to use any sealants at all to keep it in the tank i used C clamps and a bit of the tanks frame for the top and used egg crate at the bottom to keep it from swinging out. I secured it and test filled the tank to make sure it would hold and it worked well.

To This point i have only coated the front of the bg for a few reasons. 1. i was worried about scratching the glass if i dont want to stick with it..
2. i noticed a lot of people have not coated plumbing areas or the back of theirs.

Question is what should i do coat it to be safe or will it be fine with the back and plumbing areas with the extruded polystyrene exposed.? i have a load of feeder guppies for guinea pigs (there going to die anyway) but i do NOT want my over sensitive comps to be killed.

 

[Noto]

Does your polystyrene still have a strong smell? If so I suggest airing it out a while longer before adding fish. I'm not sure what that 'new foam' smell is, but it might be remnants of the foaming agent used in polystyrene manufacture.

Polystyrene itself is very inert and should pose no trouble to your fish.

 

[Pharaoh]

I agree. the polystyrene should be OK.

 

[lionshare]

thank you for replying.

No it does not have a scent anymore really i have taken my sweet time on this project almost 2 months. i liked it then i didnt but im back to liking it again lol what i may do is just cover the area in the plumbing area that was cut and sanded with the dremmil. 90 percent of the back is uncut so il just leave those areas if you think it should be fine.

i have tester fish but dont plan to be adding the future lucky fish till after xmass to be safe they seem happy in there temp home.

i just wanted to make sure cause i read it is safe in lakes but nobody that did not cover the entire foam explained why or if it made a difference.
thanks guys

 

[bob965]

It won't hurt anything to have the exposed foam contacting the water. I would be more worried about just wedging egg crate against it to secure it. It's going to be very bouyant, and if it works loose, you could launch all your fish out of the tank.

 

[kallmond]

If you've coated it in quickcrete, you could mist the polystyrene with acetone.

1 tsp of acetone diluted into 1/2 cup of water would melt an entire sheet of styrofoam. Acetone is water soluble, so you could then spend 15 minutes with a hose and rinse it all off leaving you with only the concrete.

Of course you'd want to soak your concrete for a while to leech the lime out.

If your coat of concrete is sturdy/thick enough to stand on its own, this is what i'd do.

 

[lionshare]

It won't hurt anything to have the exposed foam contacting the water. I would be more worried about just wedging egg crate against it to secure it. It's going to be very bouyant, and if it works loose, you could launch all your fish out of the tank.

I put 2 layers of egg crate so it goes up the bg about an inch its going to have sand and alot of stones on top of that and it is a very tight fit against the bg and glass. At the top it has 2 C clamps and i cut slots out of the tanks frame so the clamp is under the lip of the rim against the glass for extra support. the bg has the lip of the rim as a small back up. If it was going to come flying out i think it would have to take the whole top frame with it i hope lol i water tested it even before coating with cement and it worked i also pretty much picked the tank right up by the bg and it held.. i guess time will tell live and learn if it goes wrong.

 

[bob965]

Oh, well that sounds pretty secure then. I guess you're really determined not to glue anything to your tank

 

[lionshare]

Oh, well that sounds pretty secure then. I guess you're really determined not to glue anything to your tank

lol yea the first few threads i read they ended up taking it out i dont want to go through that.. Also for cleaning behind it or if i decide to change designs. To be honest it is nothing like what i planned and i hated it lol but it grew on me after small changes a little bit at a time. But now that its coated im starting to really like the look.

I also decided to just coat the inside of the plumbing area with a few coats and leave the parts that touch the glass. Im not to sure about the melting the foam part the concrete seems soft to me its had 3 coats so far but i can basically sand the brush streaks out with my fingers it is going to get another 3 coats but the last thing id want to see is it crumble to pieces