zinc stuck in freshwater cooler

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jann

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Joined
Apr 23, 2012
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When I tried to remove my zincs for replacement the copper cap broke off the zinc.
leaving the zinc in the engine...how do you get it out....any suggestions
thanks
 
Remove the cap and pull it out. Sometimes but not often needle nose pliers will get it, but usually the pliers plus zink is too big to get through the hole. Fast drying glue on a stick might also get it.



David
 
A small tap has occasionally worked for me - sometimes it will bite, and sometimes it won’t.
 
Left hand thread drill bit then a extractor if it does not come out with the drill bit.
 
jann said:
When I tried to remove my zincs for replacement the copper cap broke off the zinc.
leaving the zinc in the engine...how do you get it out....any suggestions
thanks
Click to expand...

Your thread title refers to the "fresh water cooler" so I'm going to assume that you actually mean the "heat exchanger", if so you may have to remove the end cap to get it out.
 
Last edited:
I have found they eventually disintegrate to nothing inside the HE.
I cant remove my end easily. What I have done when they break off, punch them into the HE to clear the hole, and attach a new anode.

They make aluminum pencil anodes. I plan to switch to them.
I just bought a new set of aluminum anodes for the rudder and shaft and trim tabs.
 
Not good to have bits of anodes plugging heat exchanger tubes while you wait for them to disintegrate. Without a good electrical connection to the body of the exchanger those bits may last a long, long time.
 
This happened to me when I changed mine. When I opened the caps on the exchangers I found two in one side and three in the other. Clearly an ongoing issue.

I'd recommend opening the cap and removing old zinc remains. Also the perfect opportunity to shine a flashlight and inspect the exchanger.
 
Zincs fall off when you unscrew the brass nut for two reasons:


1. They weren't tightened enough when they were first installed so they unscrew from the brass nut when you try to remove them.


2. You wait too long to replace them. They should be replaced at no more than 50% wastage, probably less.


David
 
I have 2 anode locations on my Mainship that problematic.
In both the issue seems to be minimal clearance around the rod portion close to the plug.
I have started two oeactices that seem to help.
I coat a narrow band around the anode rod in the liw clearance area to minimize / delay corrosion
I remove and inspect the anode more frequently. The anode doesn't need replacement that often but it gives me a chance to vlean off tbe corrosion products and recoat the band if necessary.

Together they have eliminated broken anodes remaining in the resoective HEs
For clarification I am in fresh water and use alum amodes but above should help any material.
 
Bacchus said:
I have 2 anode locations on my Mainship that problematic.
In both the issue seems to be minimal clearance around the rod portion close to the plug.
I have started two oeactices that seem to help.
I coat a narrow band around the anode rod in the liw clearance area to minimize / delay corrosion
I remove and inspect the anode more frequently. The anode doesn't need replacement that often but it gives me a chance to vlean off tbe corrosion products and recoat the band if necessary.

Together they have eliminated broken anodes remaining in the resoective HEs
For clarification I am in fresh water and use alum amodes but above should help any material.
Click to expand...

Don't understand "recoat the band" ?
 
Bacchus said:
I have 2 anode locations on my Mainship that problematic.
In both the issue seems to be minimal clearance around the rod portion close to the plug.
I have started two oeactices that seem to help.
I coat a narrow band around the anode rod in the liw clearance area to minimize / delay corrosion
I remove and inspect the anode more frequently. The anode doesn't need replacement that often but it gives me a chance to vlean off tbe corrosion products and recoat the band if necessary.

Together they have eliminated broken anodes remaining in the resoective HEs
For clarification I am in fresh water and use alum amodes but above should help any material.
Click to expand...

What do you coat that band around the pencil with?
I have same problem, a tight clearance where anode passes through the HE outer shell and the pencil anode will swell with corrosion and lock itself in place.
I also leave it there a long time between replacements, mostly cause I know it will be jammed in place. Mine are 4" long and 1/2" wide anodes with a 3/4" brass thread fitting where it screws in. I suppose I could drill open the shell some more.
 
Last edited:
So far I have used a coiple coats of nail polish.
I have not but am thinking I might try a short piece of shrink tubing to see if I have enough clearance.
I am also considering uding locktite when replacing the rod in a plug. I will test to ensure I have goid continuity.
I have also ground the threads off an old plug so when a rod sticks in the HE I can screw in the modified plug and continue tp rotate the plug to rotste the rod and/or pull it out w vise grips on the hex head and can tap w sm hammer to break it free.
 
Boatpoker
The coating isn't a permanent fix as it erodes or the alum begins to react at the edge or under the coating. After cleaning the rod I can reapply the nail polish band.
 
Still not sure of exactly where you are putting "nail polish" but any dielectric material between the anode and the heat exchanger body will inhibit the galvanic action that is the purpose of the anode. The more complete that barrier, the longer your anodes will last because they can't corrode as they were designed to do.
 
boatpoker said:
Still not sure of exactly where you are putting "nail polish" but any dielectric material between the anode and the heat exchanger body will inhibit the galvanic action that is the purpose of the anode. The more complete that barrier, the longer your anodes will last because they can't corrode as they were designed to do.
Click to expand...

He puts it on the end where the anode would touch the shell of the HE. That helps keep it from getting corroded stuck in the HE outer shell. The rest of the anode is exposed to the raw water.
 
The band I mentioned is NOT between the rod and plug where it wpuld affect conductivity.
It is arpind the outer dia of the rod adjacent to the plug threads and is the area where the HE openning is very close to the rod dia.
 
I think you could put a waterproof sealer like pipe dope on the threads of the brass-bronze end where the anode itself screws into the brass-bronze fitting. I will try it and check it with an ohm meter to verify it has low ohms. I buy the anodes and screw them into the bronze-brass fitting which screws into the HE.
Doing that may help get it apart without having to fuss with it when replacing the anode.
 
sdowney717 said:
I think you could put a waterproof sealer like pipe dope on the threads of the brass-bronze end where the anode itself screws into the brass-bronze fitting. I will try it and check it with an ohm meter to verify it has low ohms. I buy the anodes and screw them into the bronze-brass fitting which screws into the HE.
Doing that may help get it apart without having to fuss with it when replacing the anode.
Click to expand...
Removong the anode rod from the plug is not the issue I have and I don't think thats what started this part of the discussion.

The problem I responded to and have experienced is anode rods sticking in the HE and either unscrewing from the plug or breaking off from the plug and sticking in the HE.
 
I will apologize to the OP for the side track to the origonal post.
This evolved into a lengthy side track.
I will take some pics of what I mentioned bext time I check anodes.
Wish I had a couple of pics now
 
sdowney717 said:
I think you could put a waterproof sealer like pipe dope on the threads of the brass-bronze end where the anode itself screws into the brass-bronze fitting. I will try it and check it with an ohm meter to verify it has low ohms. I buy the anodes and screw them into the bronze-brass fitting which screws into the HE.
Doing that may help get it apart without having to fuss with it when replacing the anode.
Click to expand...

Not low ohms .... 0.0ohms. Remember you are only dealing with millivolts.
 
Perhaps you can find a smaller zinc to use. They come in a variety of sizes. It might have to be changed more often, but that's probably better than having to disassemble the cooler to remove the dead solders.
 
sdowney717 said:
I think you could put a waterproof sealer like pipe dope on the threads of the brass-bronze end where the anode itself screws into the brass-bronze fitting. I will try it and check it with an ohm meter to verify it has low ohms. I buy the anodes and screw them into the bronze-brass fitting which screws into the HE.
Doing that may help get it apart without having to fuss with it when replacing the anode.
Click to expand...

I would not suggest this. The previous owner of my boat wrapped all of the pencil zincs on the engine with thread tape. When I replaced them, they were all perfect. Every set of instructions I've ever read warn not to use thread tape or dope on the threads.
 
I don’t think they are saying use a tape on the threads, but rather “seal” the anode right next to the plug so that the anode doesn’t waste away by the plug. You are correct that you don’t want to use any sealant on the threads of the plug or you may make the anode ineffective due to the the electrical insulation of the sealant.
 
If the zinc unscrews from the plug an all thread connector nut can be screwed onto the zinc to use to pull out the zinc.

Leaving old zincs in the cooler is not a good idea. They restrict water flow and may form a hard to remove glob.
 
When you start to loosen a zinc plug, once you get a turn or so out, wiggle it aggressively with your socket wrench. This loosens the deposits on the side of the anode. Go another turn out, wiggle aggressively again. Success rate much higher in having the anode come out with the plug. Deposits on the side of the anode bind it up in the hole.
 
I switched to aluminum anodes. One size wasn't available. To resolve this, I used the next smaller size and a reducing bushing. When I pulled the anode, I did so with the bushing. Guess what, the corroded anode didn't get stuck in the housing.

The aluminum anodes seemed to last longer. I'm considering downsizing the rest of the anodes and checking them more frequently. As with all my anodes, I checked with a multi meter to make sure there was continuity through the bushing.

Ted
 
We change to all aluminum on Hobo ~4 years ago. We go back and forth from salt to brackish. We had a hard time finding the pencil anodes for the engine but someone posted about Performance Metals here. Thank you! The engine anode has a steel rod core. I haven’t had the issue with the anode breaking off in the heat exchanger since.

https://performancemetals.com/colle...ce-5-complete-aluminum-pencil-anode-with-plug
 
Thanks people
Great advise from all....I was able to remove two of them with needle nose pliers
The other one I punched in part and gentlely filed the side to allow me to get the new zink in. too much of a problem taking exchanger cap off to remove the used zinc part....hope it disintigrates and causes non problem
 
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