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 Posted: Tue Jan 17th, 2012 06:28 pm
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i_am_jim
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I ordered an anode which is to arrive tomorrow.  The ad says it's 44" long.  In an email Randy said if it was too long I should cut it off.  He said it should be 2" shorter than the distance from the top of the tank to the top of the drain valve. 

From the top of my tank to the top of the drain valve is 44 3/4", so I guess I have to cut it off to 42 3/4"

I assume the magnesium is fairly soft but the steel cable in its center may be a different story.  My current plan is to use a reciprocating saw (Sawzall).  As I recall magnesium has a fairly low ignition temperature -- is there any danger of it igniting from the friction?  I ask because it's not practical to extinguish burning magnesium.  Is there danger of damaging the anode using the Sawzall?  If so what's a recommended way to cut it?

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 Posted: Tue Jan 17th, 2012 07:39 pm
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eleent
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Hello:  I like to use a tape measure to check the real height where the anode will go.  This is done by inserting the tape into the tank and measuring straight down.  Measuring to the top of the fitting gives you a measure to the top of the threads on the anode.  Two inches less than that measure is the right length for the anode.  You can cut the anode with a hacksaw or recip saw.  There is no real danger of igniting the magnesium dust unless you are taking a torch to it, (how do I know? :cool:).  The steel wire will not be a problem.  Of course, it's best to clamp the anode in a vise and use a sharp metal cutting blade with light pressure.

Yours,  Larry

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 Posted: Tue Jan 17th, 2012 11:19 pm
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i_am_jim
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It also seemed logical to me to measure in the location where the anode will actually go, but I didn't know whether I had to reduce the length if it fit in the location.  Thanks.

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 Posted: Wed Jan 18th, 2012 05:17 am
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elenano
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If it will go in and screw down and not hit bottom, be happy. But my advice is still sound, I think. The drain valve is at or nearly at the bottom of the tank, and the bottom is domed. The anode won't be out at the edge of the tank where the drain valve is, so odds are that a couple of inches less will clear the dome.

And the magnesium is actually harder than the core wire, which is more like coat hanger wire.

Randy Schuyler

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 Posted: Fri Jan 20th, 2012 04:08 pm
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i_am_jim
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It's all done and everything seems well.

As stated in my original post, the measurement to the top of the drain valve was 44-3/4".  The measurement taken through the anode hole from the top of the threads to the bottom of the tank was 45-1/4" or one-half inch greater than to the drain valve.  Subtracting 2" would have been 43-1/4" so, using my Sawzall, I cut off one inch, with the saw kerf on the waste side of the mark, making the length 43". 

My tape measure is 1" and with the hook on the end it would not fit into the hole.  My 1/2" tape measure was too flexible to know when it reached the bottom.  Luckily I had a 4' stiff  plastic rod I ran through the  hole, to the bottom and marked the depth.

For others who are considering doing this, I was unable to remove the anode with simple torque on a 18" break-over bar & 18" cheater.  The water heater began to move before the anode came loose.  So, I rapped the handle of the break-over with a 4# hammer and it came loose easily.

The one thing that seems to be missing in all this is a torque value for tightening the anode.  I didn't know how much to tighten it.  I drew it down snug with the break-over and checked it for leaks after the tank had reheated. 

are pictures of my seven year old anode.  Randy says he thinks it's 'passivated' and not working. 

Last edited on Fri Jan 20th, 2012 04:11 pm by i_am_jim

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 Posted: Fri Jan 20th, 2012 06:00 pm
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elenano
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The picture didn't upload. Could you try again? I'd like to see this. But from your description, it was passivated.

Randy Schuyler

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 Posted: Fri Jan 20th, 2012 06:18 pm
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i_am_jim
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It actually wasn't a picture, it was a link to ==> these pictures.


Click thumbnails for larger views.

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 Posted: Sat Jan 21st, 2012 10:28 pm
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elenano
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Poor Randy! You had already sent me those and I just forgot. The busier I get and more questions I answer per day, the faster I forget stuff like this. That's passivation, all right.

Randy Schuyler

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