3D background sealant

[CJH]

I'm thinking about making a 3D background for my 150 gallon (72x20x25)

Someone in the local fish club made theirs out of foam, Great Stuff expanding insulation, and epoxy sealant.

What would be the cheapest/easiest material to use? I don't want to do concrete, it seems like a PITA and I don't want to deal with the impact on water parameters. A quart of epoxy would be something like $50

The easiest and cheapest "sealant" to use by far is Drylok, specifically their latex based masonry waterproofer. Goes on like a thick paint, dries super hard and had the nice textured finish already built it. It does not affect water chemistry.

Get the gray color and tint it to your liking.

Now, as far as foam, I don't think there is a product that is both cheapest and easiest.

Expanded polystyrene (styrofoam) is the cheapest but probably the messiest and hardest to carve detail into.

Extruded polystyrene (think the pink or blue insulation boards) is more expensive but generally less messy to carve and easier to get good detail with.

Expanding polyurethane foam is the most expensive but is easy in that a lot of the detail is achieved by the way it comes out of the can.

I like the look of backgrounds done with either carved polystyrene sheet, either extruded or expanded. Expanding insulation can be a good way to add some detail.

So I would probably use extruded polystyrene and Drylok.

 

[bob965]

Now, as far as foam, I don't think there is a product that is both cheapest and easiest.

Expanded polystyrene (styrofoam) is the cheapest but probably the messiest and hardest to carve detail into.

Extruded polystyrene (think the pink or blue insulation boards) is more expensive but generally less messy to carve and easier to get good detail with.

I found expanded polystyrene to be almost totally unusable. Every surface you carve will just look like it's covered in tiny balls. Extruded polystyrene works much better, but I would hardly call it less messy. I was covered in fine blue dust from head to toe after I worked on it. If I had to do it again, I'd look into using a hot wire to cut it to reduce dust. However you choose to carve it, make sure you do it in a well ventilated area, as it releases styrene gas when you cut it, sand it, heat it, etc. It's not really all that expensive. A 4'x8' sheet of 1/2" thick foam is only about $10 bucks.

 

[FSM]

I have a can of the expanding foam stuff already, so I was going to use some of that for detail/rocky outcrop type portions and the base would be regular sheets of styrofoam, probably the pink stuff you mentioned.

 

[FSM]

The easiest and cheapest "sealant" to use by far is Drylok, specifically their latex based masonry waterproofer. Goes on like a thick paint, dries super hard and had the nice textured finish already built it. It does not affect water chemistry.

Get the gray color and tint it to your liking.

thanks, that looks perfect.
Have you used it before?

 

[CJH]

thanks, that looks perfect.
Have you used it before?

Yes, but not in a submerged application like this. At least one background on a Cichlid forum was done this way and no change to water chemistry was found.

 

[kallmond]

I used dryloc to seal a fountain made out of brick. Its 5 feet deep, and has held water without leak for 5 years. Prior to dryloc It "weeped" at least 500 gallons of water in 4 hours.

 

[CJH]

I used dryloc to seal a fountain made out of brick. Its 5 feet deep, and has held water without leak for 5 years. Prior to dryloc It "weeped" at least 500 gallons of water in 4 hours.

Good info. Was it latex or water based?

 

[FSM]

Awesome. I read a few threads on cichlid-forum, sounds like I am good to go.

 

[kallmond]

I used the latex based stuff. The fumes are heavier than air, and I was more than a little loopy by the time I finished painting the bottom of the hole so be sure you have adequate ventilation.

 

[CJH]

I used the latex based stuff. The fumes are heavier than air, and I was more than a little loopy by the time I finished painting the bottom of the hole so be sure you have adequate ventilation.

Thanks. I meant to ask latex or oil-based, not latex or water-based. But you answered the question anyways.

I've heard the oil based drylok is really nasty.