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Thread: bulkhead fittings

  1. #1
    Sansai
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    bulkhead fittings

    in this thread i would like to discuss the bulkhead fitting.

    the bulkhead fitting is not carried by most plumbing supply houses because it is not a commonly used item. its most common use is for industrial applications, connecting plumbing to tanks.

    for ponders, it is used to connect plumbing through the wall of a pond to produce a non-leaking penetration.

    bulkhead fittings come in various sizes and can be used in varying thicknesses of pond walls.

    more on bulkhead fittings later, types, applications, sizes, installation methods.

  2. #2
    Sansai
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    a few definitions

    plumbing pipe comes in a number of sizes, expressed in inches in the u.s.a. when one refers to a 2" pipe, it means a pipe of 2" i.d. (internal diameter). the o.d. (outside diameter) would be about a half inch larger on schedule 40 pvc.

    a 2" bulkhead fitting would would be used for a 2" pipe. therefore, the diameter of the hole necessary for the bulkhead fitting would be larger than 2". when selecting a holesaw or method of putting a hole in the side of your pond, be sure to check what size is required for the brand of bulkhead fitting you bought. you do not want more than 1/16" play around the fitting.

    so when selecting a location to install your bulkhead fitting, be sure that the area is large enough to take the full diameter of the fitting. for a 2" pipe, the diameter of the bulkhead fitting will be far more than 2".

  3. #3
    Jumbo l113892's Avatar
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    Hi Joe-

    A common issue I have found is buying a bulkhead that can span the wall thickness. The ponds I have built in the past have always been framed with 1 1/2 inch thick wood. So, the bulkhead has to have a neck approx. 2 inches long.

    There can also be some discussion on the use of gaskets. If you are using a liner, example EDPM- do you need a gasket? Does the liner serve as the gasket? There is a lubricant that works good to keep the liner from twisting when the bulkhead is tightened. I don't have the name of it on me.
    Mike Pfeffer
    Northern Midwest ZNA show
    June 19 - 20, 2010
    Season's Garden Nursery
    Fishers, IN

  4. #4
    Nisai Charlespear's Avatar
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    Joe, I just bought a used (old vortex). It has a 4 inch Bulkhead.

    It's to connect to the skimmer (2in.) using a pump. (I know, not ideal) (gavity feed from the skimmer won't keep up, if I pump it from the vortex to the pond) so, I'll pump it to the vortex and spill over to the pond. I Think?

    What would I do to go from 4in to 2in? I think a reducer, and maybe a 90 elbow on the inside of the vortex forcing the water to go along the side of the vortex.....?
    Any suggestions?

  5. #5
    Sansai
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    Quote Originally Posted by l113892
    Hi Joe-

    A common issue I have found is buying a bulkhead that can span the wall thickness. The ponds I have built in the past have always been framed with 1 1/2 inch thick wood. So, the bulkhead has to have a neck approx. 2 inches long.

    There can also be some discussion on the use of gaskets. If you are using a liner, example EDPM- do you need a gasket? Does the liner serve as the gasket? There is a lubricant that works good to keep the liner from twisting when the bulkhead is tightened. I don't have the name of it on me.
    wow, you are way ahead of me!

    a little nomeclature first so we are using the same terms. a bulkhead fitting has three parts - body, gasket, and nut. some have two gaskets, i don't know why.

    the body has a neck which is the part that extends through the opening in your pond. as you say, the neck has to be long enough to go through the opening and have enough threads left for the nut to tighten.

    i put the neck through the gasket and shove the neck through the opening from the inside of the pond, then put the nut on the outside of the pond. that way the gasket is against the liner. i have always done it that way and it has worked so i assume it is correct. i have never used a lubricant or sealant with a bulkhead fitting, but i am sure there are many ways to do it for specific applications.

  6. #6
    Sansai
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    Quote Originally Posted by Charlespear
    Joe, I just bought a used (old vortex). It has a 4 inch Bulkhead.

    It's to connect to the skimmer (2in.) using a pump. (I know, not ideal) (gavity feed from the skimmer won't keep up, if I pump it from the vortex to the pond) so, I'll pump it to the vortex and spill over to the pond. I Think?

    What would I do to go from 4in to 2in? I think a reducer, and maybe a 90 elbow on the inside of the vortex forcing the water to go along the side of the vortex.....?
    Any suggestions?
    a gravity fed vortex is an amazing device, i have three retrofitted, and i will never build another pond without one. i know they work and remove an incredible amount of crud from the system. i don't pretend to understand how they work.

    generally the simpler the better and i think your plan is good. i would use a reducer as you suggest. my vortexs are homemade from plastic mix and fill tanks. i put an angle fitting inside, as you suggest, and they work very well. the water slowly swirls and the crud settles. they have 2" bottom drains and i get a thrill every time i open one and see that dirty water leave my sustem!

  7. #7
    Jumbo gregbickal's Avatar
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    Bulkheads are fine if you are working with plastic tanks. If you are simply connecting piping through the liner, I would suggest a pipe boot. You cut a hole in the liner half the size of the pipe, shove the pipe through. Then cut a washer out of rubber, same diameter as the pipe, with a hole in the middle. Put this over the liner to protect it. Then put a Marine Grade Stainless Steel clamp over this and tighten. The liner is at a 90 degree angle to the connection point, and its a continuious clamp so I would say it is way stronger than a bulkhead fitting. Have you ever tried to pull liner away from a bulkhead fitting, its pretty easy.

    With commercially made bottom drains, you have the main hole, and then you also have at least 8 bolt holes, which is more opportunity for leakage. Not to mention thats not a continous clamp, but tight and weak spots.

    Pipe boot can go through the liner at the bottom or the side. This is no problem. I often leave a slight wrinkle in the liner below vertical boots incase the ground were to settle and strech the liner. Liner has 200% elasticity.

    Here's how many pipe boots I have on my new koihouse pond:
    • (6) 6" boots through the side (about 30" down) connecting settling chamber to pump chamber and pump chamber back to pond. One boot on each side of the pipe.
    • (4) 4" boots through the bottom (5' depth) of the main pond connecting the bottom drains.
    • (4) 4" boots (2 in each settling chamber) through the bottom of the settling chamber. This is where the water enters the settling chamber from the bottom drains.
    • (4) 4" boots through the side (about 12" down) connecting the skimmer pipes from the main pool to the settling chambers.
    • (3) 3" boots through the bottom of each filter chamber for waste drains.
    • (1) 2" boot through the pump chamber as an overflow.
    So that is 24 pipe boots total at under $2 each. Imagine if you had to do that with bulkhead fittings or commercial drains. Whats a 6" bulkhead fitting cost? Whats a commercial drain cost?

    You can pipe boot anything round... Ive done 55 gallon barrells for example to use as header pools for filters.
    Attached Thumbnails Attached Thumbnails bulkhead fittings-pb230074.jpg   bulkhead fittings-pb240081.jpg   bulkhead fittings-pb240082.jpg   bulkhead fittings-p5010124.jpg  

  8. #8
    Oyagoi bekko's Avatar
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    I quit buying bulkheads for low-pressure applications. They are available here at the local feed/aquaculture store, but they are just too expensive for every day tinkering around - especially in the larger sizes.

    Instead, I use a PVC male and female adapter. EPDM gaskets sized to fit PVC male adapters can be found at the local hardware, but it is less expensive and more convenient to cut gaskets from a sheet of 1/8-inch red gasket material.

    The male and female adapters have a slight taper on the threads so they will snug-up properly when used for typical applications. However, this taper prevents the male adapter from threading all the way into a female adapter and leaves a gap wider than is usually needed for one or two gaskets and the wall thickness of an aquarium, fiberglass or plastic tank. Therefore, it is often necessary to cut a small spacer ring from the end of a slip-fit pipe fitting. The spacer ring also provides more "hip" for the gasket to seat against if the brand of male adapter you are using does not have enough hip molded into the fitting.

    Most hole saw kits are sized to accommodate male adapters for standard pipe sizes up to 2-inch. For larger sizes I use a jig saw to cut the hole.

    For anything less than about 8 feet of head, this arrangement does not leak.

    -stevehopkins

  9. #9
    Sansai
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    some bulkhead fittings are made so that you glue the pvc pipe into them, others have female threads in the neck and you screw in a connector. i have seen some that are female inside the neck and have male threads of a much larger size on the outside of the neck.


    especially interesting is the bulkhead fitting with reverse threads on the nut. after installation, if you screw a pipe into the fitting tightly enough to turn the neck, the nut will tighten further instead of loosening!

  10. #10
    Sansai
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    Quote Originally Posted by gregbickal
    You can pipe boot anything round... Ive done 55 gallon barrells for example to use as header pools for filters.
    looks like a good idea, i'll try it. big savings potential!

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