# DIY background questions



## seamount (Jul 3, 2014)

I am half-way through dry-locking my background and I have two questions

1. I have very deep and narrow cuts into my foam an I am having some trouble getting all of the drylock down there. What happens if the foam is not 100% covered in drylock? Will it absorb water and fall apart? Leach something weird? I think that it is going to be inevitable that there are not some pin head sized gaps in the drylock.

2. If I allow the drylock to dry 24 hours, can I silicone the BG into the tank and let that dry while the drylock is drying?


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## Deeda (Oct 12, 2012)

You can pour the Drylok into the narrow cuts and then tip the background to remove the excess. It's possible you may notice any non coated surfaces once the background is in place.

I suggest making sure the Drylok is completely dry before installing it in the tank, especially along the edges.


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## seamount (Jul 3, 2014)

and if there are non coated areas? What would happen?


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## Mcdaphnia (Dec 16, 2003)

seamount said:


> and if there are non coated areas? What would happen?


It depends on the type of foam. Some will start disintegrating and will float out in small plastic balls. Some will use that spot as a place to delaminate the Dyrlok and the Styrofoam. Chances are nothing will happen, at least for a while. It's unlikely you used Styrofoam with added chemicals that could harm fish.


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## seamount (Jul 3, 2014)

I used the pink stuff from home depot. Ill try my best to coat it. hopefully it wont delaminate


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## theboothsociety (Jan 3, 2012)

I used the pink stuff, and the entire back is uncoated. There should be many layers of dry lock on the front to coat the whole thing and make it hard. I know many people who have exposed pink foam in there tanks from coming apart over time with no ill effects. However on my BG, the back is exposed, but not to water. I siliconed the back to the tank, then I siliconed along the bottom and top seam, so NO water goes behind my BG. But if you're putting heaters and filters behind the BG, you obv need water to flow behind and through the BG. There is also a product called Pond Armor (home depot) a little expensive but it makes a hard clear coat on top of the dry lock to protect it from chipping away.


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## natpodu77 (Jul 18, 2014)

Hello, for those of you using drylok on top of pink foam, how did you adjust your measurements for the tank, did you cut to fit the exact measurements of the tank, or take an inch or half an inch off on the sides to make up for the buildup of the drylock on the foam? :-?


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## seamount (Jul 3, 2014)

Yes I took about an inch off on one side. Carved out my design, and then cut the entire background into three pieces so I could get it ino the tank. After coating it, I think it really only expanded like 1/4 I an inch. Not much


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## Mcdaphnia (Dec 16, 2003)

Expanding a piece of glass is a lot. If the foam bends the glass....


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## seamount (Jul 3, 2014)

expanding the glass? Im just talking about how much girth the drylock adds to the foam


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## Mcdaphnia (Dec 16, 2003)

seamount said:


> expanding the glass? Im just talking about how much girth the drylock adds to the foam


I thought you were referring to the expansion of the foam after it hardens. I had to repair two 75 gallon tanks with half inch thick glass after someone else put a Great Stuff background into them. Once the foam hardened, it continued to expand, breaking through the end glass in one tank, and snapping the back glass in the other.


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## seamount (Jul 3, 2014)

dang that sounds like a nightmare


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## theboothsociety (Jan 3, 2012)

the dry lock does add some thickness to the background. you should be good with an inch. id suggest not dry locking or at least not heavily in the areas where it goes together, otherwise it won't fit together as seamlessly. I siliconed all my pieces together in the tank with black silicone and then touched up the seams with dry lock once siliconed into the tank.


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