Tuesday, June 28, 2022

Reusing Heat Exchanger Zinc Cap

Reusing Heat Exchanger Zinc Cap

<<< Zinc ---- Cap >>>
The Zinc Anode for the Universal M25-XP heat exchanger is in two parts. The Zinc and the Cap.

There must not be any insulation between the zinc and the Cap nor between the Cap and the body of the Heat Exchanger. The whole idea is to allow the zinc to corrode rather than the body or tubes of the heat Exchanger.

The problem is that the screw thread of the Zinc corrodes with the metal (Brass?) of the Cap. As the Zinc corrodes during it's stay inside of the Heat Exchanger, the zinc is washed away in the flow of the salt water that passes through the Heat Exchanger. So when it's time for the zinc to be replaced, it's in a pretty weak state and often breaks off when trying to remove it from the Cap.  <<<< Just like this.

I know, change it more often. Will do!

I tried drilling the zinc out, gave up pretty quick.

Then I tried Barnacle Buster !!!! Wow!

As it happens, I have a spare Zinc Cap from a previous change out, so I'm seeing what happens.

Here's what it looks like after 48 hours
The remnants of the zinc have gone and the threads are clean.

It looks kinda grotty, but in fact is is extremely clear of the debris from the old zinc

The Cap's end gives a clue.

By the way, I used a pair of stainless steel tweezers to pick the Cap out of the Barnacle Buster, the tips of the tweezers have that similar black color now.

This pic shows the Cap after literally 2 minutes of wire brushing using a brass wire brush.

This is after rinsing and drying.

I have no issues with using this as the Cap during a future heat exchanger zinc change.

The stores sell the zincs either with or without the Caps, I have a couple of spare zincs without the caps.

Now I have 2 usable Caps.

Love making progress, even on the little things.

See you on the Water


1 comment:

  1. Wow, lots of electrolysis on that cap... looks very pink. I guess the Zinc is really important! I wonder why some engines have them and some (like mine) do not.


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