annode replacement Al or Magnesium?

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techntrek

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Topic: annode replacement Al or Magnesium?
Posted: 25 Oct 2015 at 7:38pm

Yup, that is usually how they "wear".

Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual

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Posted: 25 Oct 2015 at 5:13pm

Thought i'd add a picture to my last post. Here is a one-year old magnesium anode, perhaps 10%-20% or less corroded. There seems to be a center pin onto which the magnesium is cast, meaning that if the bit near the plug end continues to corrode, it will not break off and fall into the water heater tank. It looks right from a corrosion perspective, too, in that the most active section is nearest the tank wall.

Best regards, Jim
2015-RP178
TV 2015 Audi Q7 TDI and 2017 Ford F150
At home in "Our Pod"

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Posted: 23 Oct 2015 at 5:35pm

Aluminum is more "noble" than magnesium, from a galvanic corrosion perspective. See the Wikipedia article https://en.wikipedia.org/wiki/Galvanic_series for an explanation. What this means in practice is that the magnesium rod will react more quickly and massively than an aluminum rod. In ships, sacrificial anodes protect hull plating and sea water valve intakes. The US Navy uses zinc anodes since magnesium doesn't quite last as long and zinc is a little more welder-friendly.

These anodes are so inexpensive, I will always go for the magnesium instead of aluminum.

Best regards, Jim
2015-RP178
TV 2015 Audi Q7 TDI and 2017 Ford F150
At home in "Our Pod"

techntrek

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Joined: 29 Jul 2009
Location: MD
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Posted: 19 Oct 2015 at 11:23am

My anode was like kymooses, after 5 years it still didn't need it but I did it anyway.

Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual

kymooses

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Posted: 19 Oct 2015 at 9:07am

There are reasons for each, Magnesium is the usual standard, but if you camp places where the water is ever sulphurous smelling you'd maybe want to consider the Aluminium as it does not harbor the microbes that can contribute to the smell as much as the Magnesium ones.

One of the Suburban water heater manuals says that the Magnesium one should last for more than 1 year, I've had mine in several years now in fact. If yours degrades super quickly they mention using Aluminum ones as they react slower. But it does say either can be used.

Personally, Magnesium comes in them from the get go from the manufacturer so I stick with that because well, that's what they had in there. I'm replacing mine this year for the first time in 5 years with a new Magnesium one. Not so much that it needs it as the old one still looks pretty good, but at this point I figure it's time to rotate it out along with other Pod things that need doing on this time schedule.

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jstoy

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Joined: 21 Apr 2015
Location: Glenside pa
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Posted: 19 Oct 2015 at 8:37am

I am going to need a new annode rod for my Hot water heater for next spring. Doing a search, I see that you can purchase either Aluminum or Magnesium. Does it matter what kind of replacement as long as it fits the water heater?

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techntrek Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group - pHp Joined: 29 Jul 2009 Location: MD Online Status: Offline Posts: 9062	Topic: annode replacement Al or Magnesium? Posted: 25 Oct 2015 at 7:38pm
	Yup, that is usually how they "wear".
	Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual

Q7-retired Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 26 Dec 2014 Location: Pittsboro, NC Online Status: Offline Posts: 100	Posted: 25 Oct 2015 at 5:13pm
	Thought i'd add a picture to my last post. Here is a one-year old magnesium anode, perhaps 10%-20% or less corroded. There seems to be a center pin onto which the magnesium is cast, meaning that if the bit near the plug end continues to corrode, it will not break off and fall into the water heater tank. It looks right from a corrosion perspective, too, in that the most active section is nearest the tank wall.
	Best regards, Jim 2015-RP178 TV 2015 Audi Q7 TDI and 2017 Ford F150 At home in "Our Pod"

Q7-retired Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 26 Dec 2014 Location: Pittsboro, NC Online Status: Offline Posts: 100	Posted: 23 Oct 2015 at 5:35pm
	Aluminum is more "noble" than magnesium, from a galvanic corrosion perspective. See the Wikipedia article https://en.wikipedia.org/wiki/Galvanic_series for an explanation. What this means in practice is that the magnesium rod will react more quickly and massively than an aluminum rod. In ships, sacrificial anodes protect hull plating and sea water valve intakes. The US Navy uses zinc anodes since magnesium doesn't quite last as long and zinc is a little more welder-friendly. These anodes are so inexpensive, I will always go for the magnesium instead of aluminum.
	Best regards, Jim 2015-RP178 TV 2015 Audi Q7 TDI and 2017 Ford F150 At home in "Our Pod"

techntrek Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group - pHp Joined: 29 Jul 2009 Location: MD Online Status: Offline Posts: 9062	Posted: 19 Oct 2015 at 11:23am
	My anode was like kymooses, after 5 years it still didn't need it but I did it anyway.
	Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual

kymooses Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 01 Aug 2010 Location: Louisville, Ky Online Status: Offline Posts: 1807	Posted: 19 Oct 2015 at 9:07am
	There are reasons for each, Magnesium is the usual standard, but if you camp places where the water is ever sulphurous smelling you'd maybe want to consider the Aluminium as it does not harbor the microbes that can contribute to the smell as much as the Magnesium ones. One of the Suburban water heater manuals says that the Magnesium one should last for more than 1 year, I've had mine in several years now in fact. If yours degrades super quickly they mention using Aluminum ones as they react slower. But it does say either can be used. Personally, Magnesium comes in them from the get go from the manufacturer so I stick with that because well, that's what they had in there. I'm replacing mine this year for the first time in 5 years with a new Magnesium one. Not so much that it needs it as the old one still looks pretty good, but at this point I figure it's time to rotate it out along with other Pod things that need doing on this time schedule.
	RPod Rallies RPod Owner Map

jstoy Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 21 Apr 2015 Location: Glenside pa Online Status: Offline Posts: 20	Posted: 19 Oct 2015 at 8:37am
	I am going to need a new annode rod for my Hot water heater for next spring. Doing a search, I see that you can purchase either Aluminum or Magnesium. Does it matter what kind of replacement as long as it fits the water heater?