Despite Knowing Better...Bulkhead Gasket on Wrong Side...Options?

I actually just asked similar question in a build thread. PVC slip joints need the cleaner and glue but the threaded ones need Dope. I think. That was my question. Does a threaded pvc connection alway need the dope or a straight connection ok? I let u know

The other thread mentioned not to use the tape on threads.
 
What kind of overflow is that? Just a generic box? If so, as mentioned above, those typically need two gaskets, one on each side of the glass. That is the way the Glass-Holes overflows and many of the ghost style overflows are installed. Like this...

OverflowBulkheadInstallation.jpg


Showing gaskets on both sides of the tank wall (wood template shown in photo).

OverflowBulkheadInstallation2.jpg


If joining slip PVC connections, use only PVC cement. I usually use cleaner, but many people have success without it. There is a new product by Oatey called Fusion, which has cleaner and cement combined in one step. I am using that on my new build.

Many people tell you to not use teflon tape on PVC. They recommend using a non-hardening joint compound. While that may be the preferential and recommended way to go, if you have ever used it, you will know that it is also the messiest option. It never dries and will end up everywhere. Bill Wann, who builds commercial systems and very large private aquariums, uses silicone on the screw together joints. Just remember that the fittings are tapered and are not meant to screw in all the way. If you use teflon tape or silicone, be sure to screw in the fitting hand tight and then no more than two complete turns with channel locks or a strap wrench. I have been in the hobby since the early 80s and have always used the teflon tape without issue.
 
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I have been in the hobby since the early 80s and have always used the teflon tape without issue.[/QUOTE]

Myself as well, never had a problem.

I came across similar thread now where Redfishbluefish said“Manufacturers suggest never using teflon tape on threaded PVC”.

Have been trying to verify the best way since. I have been itching to redo my sump for a few weeks now.

My luck it will leak no matter how I do it
 
I've used teflon tape and silicone in the past.... I vastly prefer the tape even on very large threads (1.5" and 2"). Silicone is messier and I've had siliconed threads develop very slow leaks (salt creep) years after the fact. I use about twice as much tape as I would normally use on a metal fitting.

Steve
 
5 years ago I probably wouldn’t have listened to any of you and hoped for the best, but this hobby has taught me the hard way I need to listen and be patient.

After 3 trips to Lowe’s and a trip to the LFS, and hours of work. I installed a new bulkhead correctly, re-plumbed the drain using entirely PVC this time, and added a check valve to my return. Long day but feels good to have done it properly and not having to worry about it (I hope).

Appreciate all the helpful responses I got!

2B557ED5-BDA0-487F-92EA-310CC6F02FF0.jpeg
1130920B-1D31-4264-B7F8-020A030A98B9.jpeg
 
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5 years ago I probably wouldn’t have listened to any of you and hoped for the best, but this hobby has taught me the hard way I need to listen and be patient.

After 3 trips to Lowe’s and a trip to the LFS, and hours of work. I installed a new bulkhead correctly, re-plumbed the drain using entirely PVC this time, and added a check valve to my return. Long day but feels good to have done it properly and not having to worry about it (I hope).

Appreciate all the helpful responses I got!

2B557ED5-BDA0-487F-92EA-310CC6F02FF0.jpeg
1130920B-1D31-4264-B7F8-020A030A98B9.jpeg

Looks really good! It’s going to be a nice build. Patients and understanding why you’re doing what you’re doing are keys to success. We’ve a learned lessons the hard way.
 
What kind of overflow is that? Just a generic box? If so, as mentioned above, those typically need two gaskets, one on each side of the glass. That is the way the Glass-Holes overflows and many of the ghost style overflows are installed. Like this...

OverflowBulkheadInstallation.jpg


Showing gaskets on both sides of the tank wall (wood template shown in photo).

OverflowBulkheadInstallation2.jpg


If joining slip PVC connections, use only PVC cement. I usually use cleaner, but many people have success without it. There is a new product by Oatey called Fusion, which has cleaner and cement combined in one step. I am using that on my new build.

Many people tell you to not use teflon tape on PVC. They recommend using a non-hardening joint compound. While that may be the preferential and recommended way to go, if you have ever used it, you will know that it is also the messiest option. It never dries and will end up everywhere. Bill Wann, who builds commercial systems and very large private aquariums, uses silicone on the screw together joints. Just remember that the fittings are tapered and are not meant to screw in all the way. If you use teflon tape or silicone, be sure to screw in the fitting hand tight and then no more than two complete turns with channel locks or a strap wrench. I have been in the hobby since the early 80s and have always used the teflon tape without issue.

Yes it’s a generic overflow box, I followed your instructions for the re-install. Thanks a ton for all this info, it was clutch when re-doing this today.
 
Looks really good! It’s going to be a nice build. Patients and understanding why you’re doing what you’re doing are keys to success. We’ve a learned lessons the hard way.

Thanks for all your help. Exactly. Making sure to take a lot of photos and document the build, will get to putting together a build thread as soon as things settle down over here.
 
Unfortunately, the bulk head is leaking anyway. I decided to wait for a day before filling the sump to see if the display leaked, it didn’t, so I began to add water volume to fill the sump and sure enough the bulkhead is leaking from the threads despite having re-done it properly yesterday. Would appreciate any advice as I’m in a dire situation now. Contemplating going to get silicon and filling around the threads where the bulkhead nut is (source of the leak).
 
The bulkhead in the sump is leaking, or the display?

Did you use two gaskets on the overflow bulkhead?
 
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Do it right or you could be replacing more then a little pluming and a gasket. Like your hardwood floor and drywall plumbing isn’t a place to cut corners.
 
Yeah, you need a gasket under the bulkhead flange inside the oveflow box and then a second one between the box and the tank wall otherwise water will get to the threads.
 
Figured out the problem. The previous bulkhead was a bigger schedule 80 bulk head (which is what the display tank was drilled to fit) and the replacement my LFS gave me is a standard bulkhead, so there was way too much extra space (SMH!). I also didn’t know I needed a gasket inside the overflow box, between the flange and overflow, I thought I only needed it between overflow and tank glass, and I have another between nut and tank glass.

For tonight, I went and got silicone, unscrewed the bulkhead nut, filled the space around the threads from the tank, and am currently letting it dry before re-tightening it. I plan to re-do the plumbing from the tank (AGAIN!) next weekend, but do we think this should hold for now?

3EDB16AD-F45F-4E3A-88FB-CD7C934F8C78.jpeg
A654435F-FC5C-4B9F-89C8-54ED1FDBF7AA.jpeg
 
The bulkhead in the sump is leaking, or the display?

Did you use two gaskets on the overflow bulkhead?

The slow leak was coming thru the threads of the bulkhead in the display. I used two gaskets, one in between the overflow box and the glass (inside), another between the glass and the nut (outside). Should I add a third between the flange and overflow box inside the overflow box?
 
Do it right or you could be replacing more then a little pluming and a gasket. Like your hardwood floor and drywall plumbing isn’t a place to cut corners.

Definitely. Ironic that I did it right yet still sprung a slow leak. One more time to do it really right. May have to take even more extreme measures to make sure this doesn’t happen again.
 
You don't need one between the glass and the nut. That's prob why it leaked. You need both gaskets on the wet side (inside tank) at every junction.

Thanks for this. When I re-do I’ll eliminate that gasket, add another inside the tank and use a schedule 80 bulkhead. Do you think I should cut the nut side gasket off now before tightening the nut back up where I added the silicone?
 
Looking at your pic I also don't think you need sch80. If silicone is not cured yet, take it out, move gasket to the right spots, and tighten is pretty hard. Gaskets create a seal so water can't get to the threads. When tightening it, hold the bulkhead as closely to the center of the hole as possible. It should hold.
 

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