silicone acrylic to glass

[shrimphead]

is it ok to silicone acrylic sheet into a glass tank, i'm trying to make a sump and also an overflow. the problem is the bottom of the tank has these brace stripps running along the bottom so i can't just put a square piece of glass in as the bottom isn't square so i'm thinking of using acrylic, is there a special silcone that any of you would recommend

 

[Toddrtrex]

All 3 of my sumps are glass tanks with acrylic baffles that I siliconed in place -- the oldest one is 7+ years old and still holding great.

 

[IslandCrow]

As long as it's not critical that you don't have a perfectly watertight seam, you can get away with this. I've used acrylic in glass tanks for both sumps and overflows without a problem. I just find it easier to work with. Basically, the silicone adheres very well to the glass and is then able to anchor the acrylic in place (and does stick to it to some degree). If done correctly, it's pretty watertight and quite secure. Just try go get silicone on both sides of the acrylic if possible.

As for type, any aquarium safe silicone will do. GE Silicone 1 is supposed to be reef safe, but I hear rumor every once in awhile that they put mildew inhibitors in some of those as well, so I usually just stick with the silicone for aquariums you can find at Lowes. It's a little more expensive, but with the realitively small amounts I use, the peace of mind is well worth the additional cost.

 

[lordofthereef]

I agree with Todder. For simple baffles, I wouldn't worry about using silicone on acrylic. I just got rid of a three year old sump that had no issues with acrylic baffles siliconed to glass. I would not trust siliconing acrylic to glass on anything that is providing necessary structural support (ie tank walls and the like).

 

[shrimphead]

some's going to be used for sump baffles some overflow and some tank dividers, got 3 6ft tanks, the price of acrylic over her in the uk is ridiculous, as mentioned before acrylic is alot easier to work with but might just try on get some glass, depends on the price difference

 

[lordofthereef]

I am not sure I would so much recommend it for an overflow. Again, not that have had any issues, but an overflow isn't a place where you want a seam to pop. A small leak in a baffle is FAR more forgiving than a small leak in an overflow.

FWIW I just did a larger sump with glass baffles since I needed thicker material and having the glass cut was actually cheaper than buying a large sheet of acrylic. The acrylic would have been about $60 whereas the cut glass only cost me $40. I did have to wait a little under two weeks to have my glass cut though...

 

[aleonn]

Generally, silicone adheres much better for glass baffles to glass tanks.

As mentioned above, I use GE Silicone 1, and make sure there are no mold inhibitors. I let the silicone cure/dry for about a week before contacting with water just to play it safe.

 

[jeff@zina.com]

Keep in mind that a major issue of acrylic baffles failing isn't the silicone, it's the fact that the acrylic is too thin and flexes. Silicone will seal, but not provide any real adhesion and, if the baffle flexes, it will break the seal.

Jeff

 

[iamwrasseman]

i would use thicker plexi that you think you need , say 3/8" for a 75 gallon tank and caulk from both sided as a precaution . you can even cut thin 1" stripes and use laying on the tank glass for more surface area . be very careful if your cutting it on a table saw as it loves to become a Frisbee and end up across the room . anything in its way will get cut including you .

 

[davocean]

Agree, if acrylic is too thin it can flex and pull away.
And glass to glass is a better bond.
But my current sump has acrylic baffles, cause that's what I had laying around, I just used 1/4" and added 2"strips between baffles for tensile strength.
I was also careful to not make baffles too tight for fear of them swelling or flexing more than glass.
Not pretty, but it works.

 

[mcoomer]

If you have access to E6000 in the UK take a look into using it to bond your acrylic to glass. E6000 is a thin adhesive that you can get in clear or black. I found that it's kind of difficult to work with because it's thin so I used E6100 which is the same adhesive but in a non-slump formula. I used E6100 to put a floating coast to coast overflow in my 6' glass 180. Good stuff.

Mike

 

[RocketSurgeon]

I used .25" Lexan for baffles in my 40 gallon breeder. so far, so good. Everyone has said it will give way sooner, than later. I'm taking my chances, that it will be later.

I siliconed some spacers between my baffles. This causes the flex to transfer through both pieces instead of only one. the single baffle on the other side for the fuge has quite a bit of bow in the middle. I'm thinking of installing another brace on it somehow.

The picture doesn't show the bulge to the middle reservoir well, but it is there. I thought the weight to the water in the return reservoir would keep it straight, but I was wrong. I'm thinking that will be my first baffle that gives way.

I use the RTV silicone.

http://www.grainger.com/Grainger/GENERAL-ELECTRIC-Clear-Silicone-4UH12?Pid=search