leaking 5/8 pipe fitting on H 34 water tank

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jim oursler

Bottom fitting leaks, the water outlet on the port side tank. Removed fitting and replaced using teflon pipe tape. Still leaks. Can you suggest a permanent epoxy to apply to the threads?
 
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Peggie Hall/Head Mistress

You don't want to use a permanent sealant

If you do, it'll be impossible to replace the hose without damage to the tank. First, figure out WHY it's leaking and exactly where...whether the hose just isn't sealing or the tank fitting has cracked...or--if it's new hose, you bought the wrong size (fresh water hose is 1/2", not 5/8"). If it's new hose, replace it with the right size...if the thread/barb fitting has cracked, replace it...if it's the right size, but the hose isn't sealing, try two hose clamps, screws on opposing sides of the hose. If that doesn't work, it may be time for a new hose between the tank and the pump. If the female fitting on the tank has cracked, the tank will have to come out and new fitting spinwelded in...there is no sealant that will bond permanently to polyethylene.
 
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jim oursler

leak is at the threads

Thanks for the fast reply. The leak is at the physical threads and not the barbed/hose end. I replaced the fitting with a new one, same result. To pull out this tank would be major disassembly of starboard side of boat.
 
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Peggie Hall/Head Mistress

Try a new threaded fitting

And Teflon tape again. It may be that the current one has managed to get itself out of round. Or...you COULD just try a few more layers of Teflon tape and a second hose clamp. All plumbing hose connections should always be double clamped anyway.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Try a little silicone

Jim: Try a little silicone on the threads. What do you have to loose (a little more water)? If you use something like this you may be able to try something else. If you use epoxy that may be the last thing. It may still leak and you will not be able to get it apart.
 
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jim oursler

will try silicon re leaking fitting

Hi Steve, I will give your silicon idea a try as I have already replaced the fitting.
 
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Peggie Hall/Head Mistress

First, try double clamping

A hose clamp can pinch the hose, creating a "pucker" that leaks. That's why all plumbing fittings should be double clamped, and why the screws should be on opposing sides of the hose...the second clamp seals the leak.
 
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Gord

Is it Plastic Pipe nipple?

If the nipple exiting the HWT is plastic, it will eventually leak. Use a Galvanized Nipple, with Teflon Tape, at the tank. Can transition to plastic at about 6" away from HWT.
 
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Peggie Hall/Head Mistress

Fresh water tank, Gord...not hot water tank

A galvanized fitting would be ok on a metal hot water tank, but metal fittings should never be used in a plastic tank because plastic and metal have widely different thermal co-efficients...iow, they expand and contract at different rates and in different amounts. Plastic expands/contracts much more than metal...so using a metal fitting can result in a cracked female tank fitting in hot weather or a leaking tank in colder weather. You don't want to mix stainless and aluminum either...that can result in galvanic corrosion. So use only stainless fittings in a stainless tank...only aluminum fittings in an aluminum tank.
 
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jim oursler

Thanks for advice on the leaking pipe threads.

An extra 1/2 turn on the new pipe fitting did the job. It was leaking at the threads and not at the new hose. Peggy, you are correct that it was 1/2 inch hose.. and also a 1/2 inch pipe fitting on one side and hose fitting on the other. Interestingly, I did find an epoxy called PB33 that will bond, but first the polyethylene tank would have to be heated in the area.. the epoxy was $15, but the special tool that disrupts the poly molecules was $300. I knew that if i used an old heat gun I was sure to screw it up. If theh 1/2 tunr hadn't solved it, I would probably have gone with silicone on the threads, but as Peggy says, this polyethylene is slippery stuff. Glad you are all here with sage advise.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
FYI

Jim: FYI, 3M is now making some type of glue that is SUPPOSE to work on Poly. I have not heard anything positive or negative about this product but it is worth looking into if you ever need such a product. The good thing about poly is nothing sticks to it, the bad thing about poly is nothing sticks to it.
 
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R.W.Landau

Peggie the HEROIN

Once again, Peggie shows that she knows her stuff. Peggie, I don't know how you visualize these things from afar unless you have had "hands on experience" in this for a long time. You continually fascinate me with your understanding of these systems. Dually impressed r.w.landau
 
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Peggie Hall/Head Mistress

Thanks for the compliments!

About 15 years of hands-on experience, actually...plus the combined knowledge and experience of just about everyone else in the industry and a "library" of equipment manuals and catalogs that occupies an entire wall of my office. I've never pretended to KNOW all the answers...just where to find 'em. However, a good bit has managed to stick over the years...I still get stumped sometimes, but not nearly as often as I used to. :) And I'm always glad to help...'cuz it's always been--and will continue to be--boat owners who have the problems that send me looking for solutions to 'em. Without input from y'all, I wouldn't know half as much as I do because I wouldn't have any reason to learn it.
 
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