Leaking overflow box....stumped.

[Jakepen]

Yes, so I would place the gasket on the inside of the tank bulkhead, silicone around the backside of the bulkhead on the outside of the tank, with a bit extra into the chip. Then tighten the nut handtight and a 1/4” turn more. Just remember, if you need to remove it, it’ll be a bit of a pain but doable. Make sure to use the GE silicone 1. Lowe’s or Home Depot for like $5 a tube. Takes a week to cure fully. Wipe down the glass with rubbing alcohol all over the whole and outside, including inside the chip. Proper prep allows for a great bond.

I’m a bit confused I guess. As suggested I will get sandpaper and will smooth out the area. Reefnoob I guess I can’t picture your method. Are you suggesting I silicone the area, put the gasket on then tighten it down with the nut? In this process do I put the overflow box on, or keep that off for now?

 

[Jakepen]

It looks like the chips and micro-cracks around them have actually caused the glass to bulge outward in a few places.

A few 'inward' or missing chips would not affect the sealing ability of the gasket as long as the gasket is large enough to contact smooth clean surface around them.

But outward lumps like that will prevent gasket (and the nut behind it) from seating fully and forming a complete seal.

I would try to smooth them down as much as possible with some 180 or 220 grit grade automotive grade sandpaper. Even some of the already broken bits of glass rub off, leaving some actual little chips/identations, it'll be fine. As long as the gasket is larger in diameter than the chipped area, it will still have a proper, flush surface to seal against.

As for the little circular mold marks on the gasket, you can sand them smooth with the sand paper, but I really doubt they're contributing to the leak ... especially if you have them facing the nut rather than the glass.

The chips do extend past the gasket unfortunately. Do I need a larger gasket, or will silicone do the trick?

 

[Doclight]

A seal is a seal.. Unless the hole is too big for the bulkhead you put in, shouldn't be a problem. Did you check the bulkhead for cracks? even a small one can cause a leak.

 

[madweazl]

If there is a seal on the other side of the glass (inside the tank), I'm not understanding why it is leaking from this location unless the inside of the hole is messed up too or there is a crack. To seal the external box, you could use another seal on the inside of it, followed by a plastic washer (something to provide even pressure to the seal), and then the nut that came with the bulkhead to seal it.

 

[Jakepen]

I think first I’m going to order some gaskets from BRS, and add them to the inside of the overflow box, see if that does the trick.

 

[ReefNoobie88]

I’m a bit confused I guess. As suggested I will get sandpaper and will smooth out the area. Reefnoob I guess I can’t picture your method. Are you suggesting I silicone the area, put the gasket on then tighten it down with the nut? In this process do I put the overflow box on, or keep that off for now?

Here’s some photos and an explanation for what I mean. My tank is not drilled yet so keep that in mind.

here is the bulkhead and gasket sitting on the outside of the tank

this is how the gasket should sit on the inside of the tank

this is the nut that holds everything in place. Apply silicone to the thread on the OUTSIDE of the tank and tighten down the nut. This also includes using the overflow box so be liberal with the silicone. Make sure it’s in the threads and has a good bead to adhere to the acrylic box.
All this should be done after sanding the protruding pieces of glass that the others pointed out. Hope this helps a bit more, I know pictures help me out haha.

 

[Jakepen]

Reefboob why do I want to apply silicone to the thread? Won’t that make it so I can’t take it off?

 

[ca1ore]

Putting a gasket under the flange will not prevent water from leaking from the external box, and it will mean that the removable weir will sit slightly further from the inside wall of the tank. Not a problem necessarily but stuff will grow back there. If the chip extends past the external edge of the gasket then that's your problem. I'd not futz with putting silicone on the threads. It's a perfectly acceptable way to seal threads, and one skimmer manufacturer does it in lieu of Teflon, but it's unnecessary here. You just have to find a way to seal that chip. If it were me, I'd just buy a sheet of gasket material and cut a bigger one; or just use a gasket from a larger bulkhead adjusted to fit around the one you have.

 

[Jakepen]

Putting a gasket under the flange will not prevent water from leaking from the external box, and it will mean that the removable weir will sit slightly further from the inside wall of the tank. Not a problem necessarily but stuff will grow back there. If the chip extends past the external edge of the gasket then that's your problem. I'd not futz with putting silicone on the threads. It's a perfectly acceptable way to seal threads, and one skimmer manufacturer does it in lieu of Teflon, but it's unnecessary here. You just have to find a way to seal that chip. If it were me, I'd just buy a sheet of gasket material and cut a bigger one; or just use a gasket from a larger bulkhead adjusted to fit around the one you have.

Yeah I thought about this as well. Would this work?

 

[Jakepen]

And this to punch a hole?

 

[ca1ore]

Excellent, I've used similar neoprene sheeting. Works fine. I'd make the gasket the full height of the external box. And do it for both bulkheads just in case the thickness is different than the bulkhead gasket.

 

[Jakepen]

Ordered, will report back Wednesday. How important is it that I cut a perfect 1.5” hole? If I can’t get the gasket prefectly snug over the bulkhead, will that cause a leak?

 

[ca1ore]

Nope

 

[ReefNoobie88]

You’ll be able to remove it, just not easily. It’s another option is all.

 

[Jakepen]

You’ll be able to remove it, just not easily. It’s another option is all.

Absolutely, which is what I will resort to if the extra gasket does not work. I appreciate all of your help reef

 

[ReefNoobie88]

Absolutely, which is what I will resort to if the extra gasket does not work. I appreciate all of your help reef

Anytime, that’s just another great thing about this forum and hobby. Anything else just let me know. Hopefully you figure it out as I’ve started to drill my tank for the modular marine overflow today. I’ll be finished in an hour or two!

 

[Jakepen]

Well this is what I ended up with. Leaks so much worse, from both sides.

 

[redfishbluefish]

What's on the back of that tank? It looks to be some kind of textured surface. You want that gasket up against a clean, flat surface.

 

[Jakepen]

What's on the back of that tank? It looks to be some kind of textured surface. You want that gasket up against a clean, flat surface.

Paint. It’s not the paint that is causing this, I didn’t have the water in the tank up to the overflow. I simply filled the box on the back with water.

 

[Jakepen]

Once it got to the bulkheads and nuts, started leaking. Pouring actually.