I changed my HX zinc last week for the first time when we were hauled for the winter. I am wondering if the new zinc is self sealing when it threads into the Hx or does some type of sealant need to be applied to the threads. The old one appeared to have "pipe dope" on the threads. I did not have any with me when I changed it so I used the Yellow (oil resistant) Teflon tape. But now I am second guessing my self. The raw water system is drained so if I need to change it now is the time. Thanks for your input.
Cory, take the Teflon thread stuff OFF. The bronze zinc holder needs to have positive connection to the HX thread. By isolating it, you are preventing the zinc from working. This is a normal approach to the issue, and I mistakenly did the same thing years ago until I asked the same question. Even without pipe dope or Teflon thread, it will not leak. If it does, get a new zinc holder. Sometimes they sell zincs without the holders, but my experience is that it's getting harder to find just the zincs these days. Marketing and money, I guess.
Thanks You!
Cory : Let me expand on Stu's advice.
The brass Zn holder has a tapered pipe thread and the holder threads should seal themselves as they are screwed in.
You want metal to metal contact so you get the best "electrical path" so the Zn will sacrifice and not the copper inside the HX. To get that best contact, here's what I do:
Take a battery terminal cleaning tool (2 peice tool for about $5). With the male portion put it in the HX hole and twist so the metal brushes really clean the female threads and remove any corrosion. Take the female portion and clean the male holder threads. The tip of the male portion will also clean the female threads of the holder. Then you should be good to go!!
A few thoughts
I am no expert on zincs. But I was told that in fresh water zinc doesn't work too well due to surface corrosion. On my shaft I use aluminium? or maybe tin? the local dealer has them. I don't know if you can get the HX zincs in a different metal.
Maybe some of the more knowlegable people on this site can enlighten me.
Jim : I'm certainly not a wizard on Zincs, but I don't really believe they are necessary in fresh water, as fresh water is not an electrolite like salt water.
I'd guess that if you need another metal to be "sacrificed rather than the copper in the HX or bronze/stainless on the shaft , it would be a more "noble" metal than copper/bronze/stainless - which I'd guess is Zinc !!
You are right, maybe some expert could enlighten us all. My thoughts :donno:
Thanks to the advice and guidance of Jack H, who recommended when changing out my hot water heater, we had minimal fluid loss, hooking up two pigtails on the back side of the heater to facilitate rehooking up the lines. worked like a charm, no need to burp the engine and heat exchanger and hot water heater are working perfectly!
Quote from: cmainprize on October 30, 2010, 09:23:26 AM
I changed my HX zinc last week for the first time when we were hauled for the winter. I am wondering if the new zinc is self sealing when it threads into the Hx or does some type of sealant need to be applied to the threads. The old one appeared to have "pipe dope" on the threads. I did not have any with me when I changed it so I used the Yellow (oil resistant) Teflon tape. But now I am second guessing my self. The raw water system is drained so if I need to change it now is the time. Thanks for your input.
If you have or anticipate a corrosion issue on the nut, you can use SuperLube on the threads of the nut. It works the same as using it as a diaelectric (insulating) grease on terminals, One would think you don't want something insulating on an electrical connection, but the reality is that the pressure between metals on the finished crimp, or on a tightened lug/post/nut/lockwasher, cuts thru to make a good connection where necessary, and where there is no physical connection (the remainder) the SuperLube affords corrosion protection. Or use copper anti seize (NAPA) on the nut threads.
kk
Guys : If I were to put anything on the threads of a anode - it would be copper anti-seize.
My thought
Researched anodes with 3 companies that make anodes. All companies said the same thing:
Salt water = Zinc
Brackish water = Aluminum
Fresh water = Magnesium
I was told zinc forms a coating (seal) on the surface and does very little in fresh water. The Great Lakes are not an electrolyte like salt water but I use magnesium to fend off stray current.
Just what I found from the anode companies.
I am in Lake.Michigan. The only zinc I have seen at my marina are on boats that came from a salt water location. Last year I had to search to find one to show a friend what they look like.