Advice needed. Bulkhead vs uniseal?

[Chriscrna]

I have two 25 gallon containers above my sump. They came with a built in 3/4 inch bulkhead.

The tanks are roto molded but were made with a flat surface for the bulkhead interface:

This one is used for salt mixing and water changes:

This one is used for a gravity fed ATO:

I would like to put a 3/4 inch ball valve on the opposite side of the ATO tank so I can have quick access to larger volumes of RO/DI if needed.

I have a couple spare 3/4 inch bulkheads laying around. The plastic on these tanks is rigid and not flexible. So I'm wondering, can I get away with using a bulkhead on this curved surface, or should I use a uniseal? Thoughts?

 

[cameronh]

I wouldn't use a bulkhead on that due to how small it is (it may not seal properly. I'm saying It may not, I can't give you a definite answer. Good luck!

 

[Jlobes]

in general curved surfaces require uniseals. Bulkheads "seat" on the gasket and flat surface.
Perhaps an easier option, is to replace the fitting in the current bulkhead with a T, using a ball valve on one leg and the 1/4 JG fitting on the other.

 

[CastAway]

I would think the small size is actually a benefit, and that the gasket would take up any gap and or deformity. Gaskets go on the wet side. And a test should be easy enough seeing as how you have them in hand.

 

[dbrewsky]

In my opinion, spend the 5 dollars for the correct fitting from the get go and avoid future failures of the bulkhead seal in the first place.

 

[Jlobes]

I would think the small size is actually a benefit, and that the gasket would take up any gap and or deformity. Gaskets go on the wet side. And a test should be easy enough seeing as how you have them in hand.

actually, BH are made for flat surfaces, not curved. This curved surface is the actual/intended use of a uniseal. As for the gasket on a BH, it goes on the flange side not the wet side.

 

[CastAway]

Wet

 

[Chriscrna]

in general curved surfaces require uniseals. Bulkheads "seat" on the gasket and flat surface.
Perhaps an easier option, is to replace the fitting in the current bulkhead with a T, using a ball valve on one leg and the 1/4 JG fitting on the other.

You win! Great idea!

This is precisely why I love this community.....someone will suggest something that makes me go, "Duuuuh, why didn't I think of that?"

Thanks!

 

[Jlobes]

Wet

Sorry to say, you are mistaken. always on the flange side

cut and paste from AZ, here: https://www.reef2reef.com/threads/installing-bulkhead-tips.34973/

Bulkhead tips:

1. Always install bulkheads clean and dry, no silicone, teflon or thread lubricants. Silicone and lubricants cause the gasket to scoot out or not seal properly. Have you ever removed an old automobile windshield or other gasketed glass? The rubber vulcanizes to the glass with time and creates a perfect seal without any help.

2. Before installing the bulkhead take a few minutes using a jewelers file, nail file or pocket knife and clean any excess flashing off both the male and female threads and from the flat gasket mating surfaces of the flange and nut. This is a common source of leaks.

3. Always install the gasket on the flange side of the bulkhead, never on the nut side, regardless if its inside or outside the tank. Installing the gasket next to the nut will lead to leaks as water travels along the threads around the gasket. Hand tighten only with maybe 1/4 to 1/2 turn additional, no more.

4. When using threaded bulkheads, again clean the excess flashing from the threads and valleys and use a stick or crayon type of thread lubricant designed specifically for PVC treads. These can be found at Lowes, HD, Ace and all hardware stores under names like Laco, Permatex and others.

I use this one and have since the 1980's with great success.
LA-CO: Product Detail - PLASTO-JOINT STIK® - Plastic Thread Sealant
It stays pliable forever and does not tear or roll out of the threads like teflon tape. My swimming pool plumbing up to 2" was all installed with this in 1983, outside in Phoenix AZ and its still pliable to this day!
Teflon tape was never designed to be used with PVC. Read this article by LASCO, one of the largest PVC fitting manufacturers in the world:
http://www.lascofittings.com/supportcenter/TheDosandDontsThreadedPlastic.asp

5. Never support any pumps or piping from a bulkhead, always use supports so weight is not on a bulkhead and gasket causing differential stresses on the mating surfaces and leaks.

6. Never screw anything to the external threads of a bulkhead, these are not standard tapered pipe threads (NPT) and will leak. They are there to screw the nut on is all and are not normally even a standard diameter like 1" etc.

Hope you get some use out of this.

 

[Jlobes]

You win! Great idea!

This is precisely why I love this community.....someone will suggest something that makes me go, "Duuuuh, why didn't I think of that?"

Thanks!

its the easiest option and doesnt require drilling another hole in your tank.

 

[Chriscrna]

Rubber gasket always goes on the inside of a tank.

Flange side is usually the wet side J.

 

[Chriscrna]

Moot point anyhow....we are off topic. Thanks for the T piece idea. I'm going to do that.

 

[Jlobes]

Rubber gasket always goes on the inside of a tank.

Flange side is usually the wet side J.

rubber gasket ALWAYS goes on the flange side, thats how they are designed to work. Doesnt matter if your flange is on the wet or dry side, gasket goes with the flange NOT the nut.

yeah, a bit off topic, but important note/point.

Glad to help with the T idea, seemed the easiest and most accessible option.

 

[Chriscrna]

As a reef hobbyist, I have never installed a flange on the outside of the tank. I've never had an application for such.

But if I did, yes, I would put the gasket on the flange side.

Just assumed everyone was thinking flange on inside. No biggie, we're all on the same page [emoji1303]

 

[Jlobes]

all sorts of reasons to put the flange on the outside, depends on your needs.

glad we got your situation solved, good luck with the plumbing

 

[cee]

Wet

wet or dry doesn't matter but it must be on the flange

 

[cee]

Oops someone beat me to it

 

[Steve Dillon]

Chris were did you get those containers?

 

[Chriscrna]

Chris were did you get those containers?

http://www.ruralking.com/ace-roto-mold-25-gallon-vertical-dome-top-tank-vt0025-18.html

 

[Steve Dillon]

Thanks