Hello all. I thought I'd post my cement background on MFK.
This first part is just a copy/paste from a post I made in September on another forum. It involves using expanding foam instead of silicone to fasten my background to the tank.
My first attempt at a 3d concrete background for a 125 gallon.
I siliconed 2 sheets of styrofoam together using "GE Construction 1200 series"
Did some carving and I noticed some pieces were coming loose. The silicone doesn't adhere well to this styrofoam. (It's the stuff that breaks into little balls.)
With a small bit of pressure I can pull apart the pieces. I can't see silicone keeping this much styro submerged.
I finally found some expanding foam for ponds(Touch 'n Foam Landscape from Lowes) and glued all the loose pieces back together. The foam is black and the can says it's safe for fish.
I did a small test to see how well it would adhere to glass.
An old glass lid I stepped on and a scrap of styrofoam glued together with foam.
It's on there hard. I pulled and twisted but they won't come apart.
Pried it off and the styro broke before the bond failed.
Once all my sheets were firmly glued together,I started to carve everything out using a dremel type tool with a drywall cutting bit.
I've got intakes on both lower corners. The heaters will be hidden back there as well.
I should have taken a pic of the mess. I filled one huge contractor size garbage bag with little balls of styrofoam.
Keep in mind I have no artistic ability.
Once I had the look I wanted,I cut it in three pieces to fit in my tank. I didn't want to risk removing the plastic trim.
I coated everything with "King Swift-Set" mixed with black concrete color.
It took 3 coats. I tried a brush but that was no good. Get a pair of dishwashing gloves and use your hands. The disposable gloves for staining will wear out in minutes.
Once the three pieces were covered to my liking,and cured,it was time to fasten them to the back of the tank.
The easiest way to use expanding foam is to lay the tank on it's back panel and just put the foam everywhere. Lay the pieces on top and press down.
This stuff expands a lot,so you should avoid putting it on the edges of the BG. That could put unwanted extra pressure on the tank.(I had stuff oozing out on both sides,top and bottom with no ill effects,but I wouldn't do it again.)
Last thing to do is slap some more cement in the seams where the pieces connect. You can't even tell it was cut.
Another day,and I added water,powerhead,and ph monitor.
Started out at 7.5 and 3 hours later,it's up to 8.5. Went up to 8.9 overnight.
I let it sit for 5 days,did a waterchange,and checked the ph. When it stabilized at 8.5 ,I put in a few test fish that are known to be sensitive. All I had were 1 inch black calvus so in they went. They were fine for days until I pulled a chunk of foam from one of the edges. The foam released bubbles of toxic gas.
Within one minute,one calvus started doing loops and died.The other got stressed but lived.
This is what it looked like with lights on. The right side has a planted tank bulb from Home Depot. I was trying different bulbs to see what I liked best.
It's been in there for 5 months now,and it's still solid.No movement at all.
This first part is just a copy/paste from a post I made in September on another forum. It involves using expanding foam instead of silicone to fasten my background to the tank.
My first attempt at a 3d concrete background for a 125 gallon.
I siliconed 2 sheets of styrofoam together using "GE Construction 1200 series"
Did some carving and I noticed some pieces were coming loose. The silicone doesn't adhere well to this styrofoam. (It's the stuff that breaks into little balls.)
With a small bit of pressure I can pull apart the pieces. I can't see silicone keeping this much styro submerged.
I finally found some expanding foam for ponds(Touch 'n Foam Landscape from Lowes) and glued all the loose pieces back together. The foam is black and the can says it's safe for fish.
I did a small test to see how well it would adhere to glass.
An old glass lid I stepped on and a scrap of styrofoam glued together with foam.
It's on there hard. I pulled and twisted but they won't come apart.
Pried it off and the styro broke before the bond failed.
Once all my sheets were firmly glued together,I started to carve everything out using a dremel type tool with a drywall cutting bit.
I've got intakes on both lower corners. The heaters will be hidden back there as well.
I should have taken a pic of the mess. I filled one huge contractor size garbage bag with little balls of styrofoam.
Keep in mind I have no artistic ability.
Once I had the look I wanted,I cut it in three pieces to fit in my tank. I didn't want to risk removing the plastic trim.
I coated everything with "King Swift-Set" mixed with black concrete color.
It took 3 coats. I tried a brush but that was no good. Get a pair of dishwashing gloves and use your hands. The disposable gloves for staining will wear out in minutes.
Once the three pieces were covered to my liking,and cured,it was time to fasten them to the back of the tank.
The easiest way to use expanding foam is to lay the tank on it's back panel and just put the foam everywhere. Lay the pieces on top and press down.
This stuff expands a lot,so you should avoid putting it on the edges of the BG. That could put unwanted extra pressure on the tank.(I had stuff oozing out on both sides,top and bottom with no ill effects,but I wouldn't do it again.)
Last thing to do is slap some more cement in the seams where the pieces connect. You can't even tell it was cut.
Another day,and I added water,powerhead,and ph monitor.
Started out at 7.5 and 3 hours later,it's up to 8.5. Went up to 8.9 overnight.
I let it sit for 5 days,did a waterchange,and checked the ph. When it stabilized at 8.5 ,I put in a few test fish that are known to be sensitive. All I had were 1 inch black calvus so in they went. They were fine for days until I pulled a chunk of foam from one of the edges. The foam released bubbles of toxic gas.
Within one minute,one calvus started doing loops and died.The other got stressed but lived.
This is what it looked like with lights on. The right side has a planted tank bulb from Home Depot. I was trying different bulbs to see what I liked best.
It's been in there for 5 months now,and it's still solid.No movement at all.
