Rimless w/Center Overflow

[mrbee2828]

Hello everyone. I have made a dozen or so tanks. Most incorporate a smaller top mounted overflow and herbie type drain and return setup. I recently built a rimless with a bottom drilled herbie setup and did a full height overflow. I'm going to be building a center overflow model next week. My question is, given silicon doesn't adhere to glass well, does the center need to be glass with an acrylic comb cover on top? My thought process is yes so it can seal to the bottom well. Most factory corner drilled tank have plastic or acrylic overflows sealed to the glass with silicon. I assume that because this isn't structural and inward facing pressure that this is ok. Thoughts?

 

[mrbee2828]

Bueller...?

 

[Jimbo662]

I think the issue is that when attaching a piece of acrylic to glass the silicone doesn't attach to acrylic as well as it does to glass. Structurally silicone and acrylic aren't a good match...but for an overflow box it shouldn't be an issue because there's no stress. Looking at mine the acrylic overflow box is attached with silicone. Regardless of whether it's a corner or center overflow there's no inward / outward pressure. Does all of that make sense?

 

[mrbee2828]

It does and that is where my brain is but something tells me it needs to be glass for some reason lol. Thanks for the reply.

 

[Pepcrylic]

You could always use a 2'' or 3'' bulk head with pvc for the stand pipe. Attach a strainer to the top to keep critters out. Cover the pvc with rock work.

I have seen many center overflow tanks with the OF box sealed with silicone

 

[Waters]

My rimless tank is set up exactly that way.....plastic overflow sealed against the glass with silicone. It is drilled from the bottom with two return lines and two drain lines. Here is a pic of it before it was set up if it helps.......

 

[Jaag]

Mrbee2828,
Did you make that intank overflow? I am looking to build another tank and want an overflow like that. my last one I used a 3 inch pvc pipe and cut it.