Foam Aquascaping?

[Cap'n]

I work with the nasty stuff every day, always while wearing a respirator. No way I would put expanding foam in my tank. Off-gasses for days, breaks down when exposed to sunlight, tiny abrasive particles.... I suggest reading an MSDS before using it.

I would, however, build a background out of foam, coat it with epoxy, resin, etc., then REMOVE the foam before placing in water. Good place to hide equipment as well.

[Black Phantom]

The thought of having the spray foam break down is not a good thing.
What about sculpting something out of high density foam, like the pink stuff from Home Depot, and then covering it with a two part epoxy paint.
Do you think this would hold up to a salt enviroment.
I've had some of the pink stuff under my sump for five years now and so far it hasn't been affected from the salt water or the salt creep.
Do you think that would work?

[Black Phantom]

Ok Here's what I've come up with so far. I'm going to build the main structure out of pink rigid foam. (no offgassing, stable, that sort of thing) Then a coat of marine epoxy to seal the foam.
I"m then going to try mix a batch of clear epoxy with black sand. I'll cover the structure with this mix to give me a rock look.
First off, where can I get black sand or fine rock in Calgary
Second, does anyone see a reason for this not to work. I don't want to put in all this work to have it fail for one reason of another.
Or let me know if you have another idea that might work.
Thanx

[muck]

Might have a bit of fun trying to keep the foam background you make stay underwater..

[danny zubot]

The foam seeler basically is styro-foam after is cures. I have mislead everyone by saying that it breaks down because after talking to my friend this weekend he corrected me. The foam didn't break down, rather break off. I guess you need to be careful not to bump the wall when aquascaping the tank because it chips away at the paint exposing bare foam. It just started to look shabby after a while.

Danny

[Black Phantom]

The floating thing is a good comment. Never thought about that.
I figure I'll silicone it to the back wall after everything is done. then after a day or two I can add the water.

[Cap'n]

Silicon is the way to go. You could even go so far as to build a frame (back, bottom, sides) out of pexi and do all your foamwork within. That way you can be sure of the dimensions, makes an easy job of glueing and you can competely seal off the foam from the water. Maybe even toss a couple rocks at the bottom of the foam stack before sculpting to give the silicon a hand.

I still think getting rid of all the foam after coating is the best solution but extruded foam is definitely an improvement over the expanding.