Anode rod - alum vs steel

[BB_TX]

Just purchased a new anode rod from local RV dealer. My old one has a steel head. The one the parts guy gave me has an aluminum head. I asked if that was OK. He said sure, the threads are the same. Young kid that did not impress me as very knowledgeable. That was the only type they had.
Now for the real experts. Is the aluminum OK? Or do I need a steel one?

[kmh3212]

The head should not matter it just holds the anode itself. It is the long Zinc anode itself that is the working part of the anode.

[firetrucker]

I think in general I'd prefer the steel head because aluminum is soft and tends to gall (tear off and stick to the steel) which could make it difficult to remove. Using teflon tape or a good pipe compound should minimize that, though.

There will also be some galvanic corrosion. While not as bad as that for steel and copper, it could still make it more difficult to remove the head.

Bob

[BB_TX]

I was concerned about the dissimilar metals. I did use several wraps of teflon tape on the threads to minimize the metal to metal contact. Will give it a try and see I guess.

[mtheo]

I would be concerned with the galling. It could cause it to be hard to remove as the aluminum is soft and tend to bind.
Mark

[bsmeaton]

I'm curious how well that would work out and will have to watch this post. Seems like it would be better than rust like I have now, but I have no idea about the issues with combining the metals.

[Ozz]

Just guessing here, as I have not seen it, but I wold assume they have a neutral material buffer, or insulator between the head and the anode rod. If we use a proper sized socket in the install and removal, there shouldn't be any problem with it, that is, if we use Teflon tape, or pipe dope....or a combination of both.
As a Pipefitter apprentice, I remember the instructor drilling into our heads, "Only the first three or four threads!" I like pipe dope with some Teflon in the mixture.
Ozz

[ols1932]

quote:Originally posted by BB_TX

I was concerned about the dissimilar metals. I did use several wraps of teflon tape on the threads to minimize the metal to metal contact. Will give it a try and see I guess.

Having had quite a bit of experience with anode rods, the head of the rod has no bearing on the operation of the rod. That being said, wrapping teflon tape around the threads helps keep the rod from rusting in the water heater. Also, the tape does not, does not keep the threads from connecting metal to metal. Suburban told me that the threads cut through the tape when screwed in. And, that's the way it's supposed to be. You need the metal-to-metal connection to complete the circuit for the rod to react properly to the water.

Orv

[BB_TX]

I didn't think the head would affect the operation of the rod. But I didn't think about it needing metal to metal contact. I guess I was thinking it was a chemical reaction rather than a galvanic reaction. But then, thinking about it, it makes sense.
I expected some metal to metal contact, even with several wraps of teflon tape since there is always some bare metal when I remove a fitting that I had taped. The old steel head always came out very easily even though it was somewhat rusted. I credited that to the tape, but it might have come out as easily even if I had not taped it. I just tighten them enough so that they do not leak. I don't lean on them at all.