Installing Bulkhead Tips

[AZDesertRat]

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:
Assembling Threaded Plastic Fittings

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.

 

[Hahnmeister]

I always rub the gasket with some plumbers silicone grease/lubricant. I dont leave it all over so it 'scoots' as you mention, but it really helps rejuvinate the rubber so it makes a great seal. This is very true for ones that you maybe used once and then left out to dry.

On a related note, whenever I take a pump off-line for dry storage and it has o-rings that can dry out, I am sure to put a bunch of grease on the o-rings so they dont dry/crack/shrink over time. I have had too many eheim hobby pumps and maxi-jets that ended up leaking just because the rubber dried out from dry storage.

 

[New2Reefing]

Crazy, I was just about to ask for tips. Ill be installing mine tomorrow. Thanx.

 

[lazyreefer]

Hmmmm, I'm confused about number 6. the threads are only for the bulkhead nut ??

How do you tie anything into the bulkhead then ?? For example, if I wanted to use PVC and it slips inside the bulk, aren't the threads on the bulk head also used to hold the PVC into it - along with some sort of rubber seal/threaded fitting ?? Surely you aren't "forced" into glueing the PVC inside the bulkhead ??

What if I wanted to tie flex hose into a bulkhead, can't I take a barbed fitting with a female threaded end and screw it right onto the bulkhead's threads ?? The threads on the inside of a bulkhead are designed to screw things into it right ? Like Loc-Line fittings or a screen of some sort.....

I understand about the need to support the plumbing.

 

[AZDesertRat]

Exterior or external threads are only for the nut, as I pointed out. Some bulkheads are threaded on the inside with NPT or pipe threads and others are slip for friction fit or glued joints. I prefer interior threaded myself so they can be reused or disassembled if needed lie for a move.

Yes interior threads are standard pipe thread like PVC fittings. Exterior threads have no taper and can be odd sizes so PVC fittings will not thread on properly and will either wipe the threads out or leak or both.

 

[Paul_N]

I have a bulkhead ? for the resident expert....:bigsmile:

I have a custom four sided overflow box I am putting on the inside of the tank. The flange will be on the inside and the bulkhead will go through the back wall of the box and then through tank with the nut on the outside. Should I use one or two gaskets? I can't figure out if I should just put one between the flange and the overflow box so it would go flange-gasket-overflow box-glass-nut or should I use two gaskets and have it flange-gasket-overflow box-gasket-glass-nut? I saw on gl*******s site that they use two gaskets with their box but they put the flange on the outside of the tank.

Clueless??

 

[AZDesertRat]

Their method is correct. Water will travel along the threads even with multiple gaskets and will seep or leak. With the flange on the outside there are no threads to leak since all you have is the flange and gasket.

Place the flange and gasket on the outside with the nut on the inside. You can then place a gasket between the overflow box and tank wall if you want but it should not leak to the outside either way.

 

[Danmgy]

So I have recently started building my tank and there are two things I have been struggling finding information about and one of them is with bulkheads! So I am REALLY hoping you or anybody can help me with this one. I am creating a center back overflow and want to use 3 1" bulkheads, the issue I am stuggling with is the distance to seperate/in between them and the distance from the edge of the tank. I want to make them as close together as possible to I don't have a huge overflow (the tank is only 55g). So my question, is there some rule or guideline as to how close you can put bulkheads together? I am nervous about them being to close and effecting the strength and integrity of the glass (the glass is 1/2" thick), but giving them to much room and I am stuck with a huge overflow.

So any ideas, suggestions, pointers, guidance, directions to point me in???

Thanks in advance :bigsmile:
David

 

[AZDesertRat]

When I had LeeMar build and drill my tank they said 2" from the outside edges or at least the outside diameter of the bulkhead away from edges or other holes.

 

[Danmgy]

When I had LeeMar build and drill my tank they said 2" from the outside edges or at least the outside diameter of the bulkhead away from edges or other holes.

So does that mean it is the outside edge of the actual plastic bulkhead with 2" distance to the edge of the drilled hole or the outside edge of the plastic bulkhead with 2" distance to the outside edge of the other plastic bulkheads? :squigglemouth:

Just want to make sure I get it right and not ruin an entire pain of glass and build but being off.

 

[AZDesertRat]

On mine the holes are 2" from both the top and side edges of the back and side walls and the two in the internal overflow are actually about 3" apart to give me sufficient room to construct a standpipe.
In this pic you can see one hole in the upper left corner, another with a bulkhead already installed in the upper right corner and a third hole in the back center for the closed loop suction.

In this pic you can kind of see the distance between the two holes in the internal overflow box.

 

[Danmgy]

I think I see what you are getting at, I will probably end up just leaving a little extra space and go with the "better safe then sorry" method.

Thanks for all the help and insight!!

 

[Aku]

Good stuff. I'm just about to turn my tank into swiss cheese. This will be helpful. Thanks for posting.

 

[tampasnooker]

Any thoughts on using Loctite to keep the nut in place?

 

[AZDesertRat]

I've never had a problem with the nut backing off unless I have been messing with the plumbing. Thats why I use plenty of unions so I can remove pumps and valves without disturbing the bulkheads.
Does Loctite make a product for plastics?

 

[Engloid]

Respectfully, I've got a little different of opinion on some of this, and would like to add my opinions and experience.

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.

I sometimes like to put a little "food safe" lubricant on the surface that the nut goes against. It helps overcome friction on a large surface, which makes it easier to get a snug fit on the gasket.

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.

I think we're on the same page here. For clarity, "excess flashing" is a defect in the molding. I don't know how to explain it, but if you buy a model airplane and all the parts are molded into one "sheet"....you break them apart and each one has a little *** on it. Good model builders will file or sand it smooth. Likewise, items like bulkheads, which aren't molded in batches or sheets, will have some seam-looking things on them sometimes.

4. When using threaded bulkheads, again clean the excess flashing from the threads and valleys and use a small amount of teflon tape or better yet the 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 don't see where teflon tape on the threads of a bulkhead will do anything other than aid to difficulty in removing it later. I have used the "food grade" lubricants on bulkhead threads too. It works pretty good.

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.

It's a really bad idea to use pipe or bulkheads to support anything more than the weight of short runs of pipe. PVC can become brittle at times, especially when cold.

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.

Agreed...however, again for clarity, the INTERNAL threads are NPT.


Another point that I haven't seen mentioned... I prefer to install bulkheads with the nut on the outside. I know it looks odd, but the BIG advantage is that it puts the external threads on the outside where they won't get all dirty and filled with salt and debris. This makes the MUCH easier to remove later down the road.

One of the most common causes of bulkhead leaks is not putting them on a smooth and flat surface. I recently drilled a hole in a bad place, at the top of a 55g plastic drum. It leaked with the original gasket. Luckily, I was able to get some 1/4" gasket material and get it to seal up.

 

[Engloid]

I've never had a problem with the nut backing off unless I have been messing with the plumbing. Thats why I use plenty of unions so I can remove pumps and valves without disturbing the bulkheads.

Adding a ball valve between the bulkhead and the union is also a good idea. Otherwise, you have to drain the tank before taking the piping apart at the union. Here's a couple pics of my sump setup in the basement. As you can see, I had the "wing it" method of planning the routing. All together, it probably took about 3 evenings after work to run all the plumbing from the upstairs display, to the sumps and back.

 

[AZDesertRat]

1. The reason you do not want any lubricants on the exteroir threads is it will allow the nut to back off with the slightest movement which is not a good idea, I stand by my clean and dry statement.

4. Again no teflon or lubricants are advised for the above reason.

Functionally it really does not matter whether the flange is inside or outside the tank as long as the gasket is on the flange side and not the nut side. There are applications where its impossible to put the flange inside like some of the Glass Holes overflow box kits.

Yes, I do use ball valves on all my plumbing but this was an article on bulkheads not plumbing.

 

[goody]

I just want to make sure I install my bulkheads correctly, so I'm upgrading to a 150g that was drilled for a closed loop system. There are 3 holes on the base of the tank. The last owner plugged the holes, which is what I want to do, so are these bulkheads still tighten these by hand?

 

[AZDesertRat]

Yes, hand tight plus maybe 1/4 turn is all it takes to seal them.