Bulkhead - What am i doing wrong?

[Kent67]

Greetings all,

I'm on my second bulkhead (broke the first overtightening) for a tank I purchased used that is drilled through the bottom. I'm trying to rebuild the overflow that it had before but cannot get the bulkhead to stop leaking. There are no obvious cracks in the tank and I've gotten it as clean as I can, several times. The O-ring gasket in the bulkhead is just slightly smaller than the hole. What am I doing wrong? I'm not supposed to be using any sealant, right? 1.25-inch bulkhead/2-inch hole FWIW.

Thanks!!

 

[The Aquatic Arsenal]

Sounds like the bulkhead might be to small.

 

[redfishbluefish]

Hole size is right for a "standard" ABS bulkhead.

As far as installation, regardless of how the bulkhead is installed, the gasket always goes on the flange side. You mentioned an O-ring. It shouldn't be an O-ring, but a flat rubbery washer looking ring. If you broke the first one, my first guess is that you're over tightening. This could cause the rubber seal to crimp-up, forming a channel for leaks. Hand tight with an 1/8 to 1/4 turn, at most.

 

[Admann]

Could I ask, should you put any lube on the gasket (silicone grease)?

 

[redfishbluefish]

I would suggest not using it....and if you do, the first thing is that it needs to be made or non-petroleum products....made specifically for rubber. Once applied, I'd wipe it off so that it was only a very very light coating.

 

[Admann]

I would suggest not using it....and if you do, the first thing is that it needs to be made or non-petroleum products....made specifically for rubber. Once applied, I'd wipe it off so that it was only a very very light coating.

Roger that, I can see the grease making it easier for the gasket to move around and wrinkle while tightening

 

[lapin]

I use silicone grease on all my flat and O ring gaskets. It keeps them from crimping in between surfaces.
You should tighten by hand with a lot of force. If you still have a leak a slight bit more (and I mean slight) might be helpful and you can use a wrench for this. Never use a wrench unless you have to.
"The O-ring gasket in the bulkhead is just slightly smaller than the hole."
The ID of the gasket should the same as the hole size. The gasket should be about 1/4 " wide and flat.

 

[theMeat]

Get a razor blade and clean surface of glass.
Gasket goes on flange side. No grease is necessary. A lil spit on threads will help you get a good hand tighten. Then another 1/8 turn with wrench and good.

 

[Kent67]

Dang. I've tried all of the above except for grease and cleaning with a razor (it's acrylic). I said O-ring but it is a flange. I've tried everything from barely finger tight to probably over tightening with a wrench, in short increments, and nothing stops the leaking. It's this one: https://www.ebay.com/itm/1-25-1-1-4...7?pageci=9ec9df66-84ef-443e-b326-e09e24c94713

 

[Admann]

I wonder if a softer compound gasket would work better with acrylic?

 

[Admann]

This just a theory. I have never owned an acrylic tank. You could try using some 220 grit sandpaper and a sanding block to see if the acrylic has any hi or lo spots. Verrry lightly, just enough to cloud the surface of the acrylic. Low spots will stay shiny and would create a channel.
If it is just one bulkhead it may be warped and works more like a wave washer.

 

[DanConnor]

so the flange and gasket are on the inside, nut on the outside, correct?

 

[ca1ore]

Pictures will help us help you!

 

[Hypan]

Yes, flange and gasket on the inside, nut outside. Also some gaskets have a ribbed side. I’ve always been told to put this facing away from the flange so it contacts the glass/acrylic

 

[Kent67]

Yep, flange on the inside and nut on the outside. No ribs on the flange, either. Photo attached.

 

[Shirak]

Do you have the correct side on the water side? The flange with the washer is in the water with the threads and nut on the outside. Try cleaning everything with a little rubbing alcohol.

 

[motortrendz]

How bad is it leaking? I also agree with the one who said to use a sand paper on a block (400grit) to ensure theres no low spot. In the acrylic causing a channel for a leak. Also if you may want to check the diameter of a schedule 80 hole it may have been drilled for a schedule 80 bulkhead.

 

[Shirak]

+1 for checking size of the hole. It should just barely be large enough to let the threaded piece through.

 

[ca1ore]

Do you have the correct side on the water side? The flange with the washer is in the water with the threads and nut on the outside. Try cleaning everything with a little rubbing alcohol.

Common misconception - doesn't matter as long as the gasket is on the flange side.

 

[redfishbluefish]

so the flange and gasket are on the inside, nut on the outside, correct?

Do you have the correct side on the water side? The flange with the washer is in the water with the threads and nut on the outside. Try cleaning everything with a little rubbing alcohol.

This actually isn't true. Really doesn't matter what direct the bulkhead is installed (short of the needs of the connections and ease of installing the nut). What is critical is that the gasket is on the flange side. So again, flange inside the tank/outside the tank....who cares....gasket is always with the flange, and keeping water from leaking.