rock made of TUFF STUFF?

[stephclay]

has anyone made rock out of TUFF STUFF foam. I was told that it is non toxic and works well for making rock shapes for the background. I just don't like the color and was wondering if cement can be coated over it once the foam has dried. any advice would be great.

thanks

 

[portabuddy]

you can use any spray foam, but remember that foam is very boyant, people that use foam for background sillicone them to the back glass or melt it away once the rock is done....

First thing you do is spray out the foam, shape it with some sand paper , then get some cement, and mix it up, You can add stones or sand to it to get the cosistancy you want, you can use concreet dyes to colour it however you want or paint the cement with epoxy paint. the problem with useing cement is that it leaches out lye into the water as it finishes curing, this raises your PH to a deadly level, and the way to avoid killing all your fish off it to soak the creation in water and do frequint water changes untill the pg has stablized to a normal level(7). this takes weeks, not days. useily about 4 weeks for the cement to fully cure. then some peope melt the foam away, useing aceitone or a toarch, this gets rid or the boyancyt issue.


Hope this helps, all this info is avalabe on any one of the 6-7 DIY background thread here for the last week...

 

[Mystix212]

I never really knew it'd raise your pH to a deadly level, Like 10+?

 

[portabuddy]

oh yah, one rock might not but it will still kill the fish. any abnormal change in ph is likley to kill you fish, like i said the lye leaches into the tank making it more alkiline...if you make a large background and use alot of concreet you can get up to almost 11(can burn....)

 

[Mystix212]

I've seen numerous amounts of tanks use huge bnlovcks of foam, carve that and coat it in epoxy. Has the same effect but concrete would be much harder to deal with? IMO

 

[stephclay]

since it is saltwater i want the concrete to act as live rock, so i"ll prolly just coat the foam and then cure it for a month or so until it is safe.

 

[portabuddy]

good plan..., some ppl mix crushed coral into the mix for the iregularity and natural look... something to think about.

 

[schaadrak]

since it is saltwater i want the concrete to act as live rock, so i"ll prolly just coat the foam and then cure it for a month or so until it is safe.

Why even use the foam at all? You can make the rock solid cement and it would cheaper. If you're worried about the weight of it add rock salt (the stuff they use in water softeners) to your mix. As the rock cures, the salt dissolves away and makes a very porous, light yet strong base rock.

Here's a link to an excellent thread on RC about DIY rocks for a reef set-up. He tried a couple different mixtures before he settled on salt. Be warned; it's a super long thread (was split like three or four times) but it has a lot of information.

 

[portabuddy]

good link i read that bout two months ago, very informitive, i will be doing this when i get my SW tank going...

 

[stephclay]

except that even with rock salt the rock background weighs 150-250 lbs. i have four 18x6x24 pcs built already and they are heavy. each rock is 1.5 to 2.5 bags of portland cement. this way i can use the cement i have, use the foam covered in cement and use my existing live rock (300-400lbs) to do the back and both sides. remeber this is 48"wide and 46" tall