Norwester
Member II
IDK...really. However, I now know zinc replacement is VITAL. ... and there's more to learn and add to this topic, I believe.
The timing of recent heat exchanger (Hx) discussion relating to broken pencil zincs forcing sailors aground...(oh, wait, that was our summer story.)
Well... yes, broken pencil zinc(s) blocked our Hx and blockage in raw water system significantly increased our engine's temperature enough to find local dock in Swinomish Channel at Twin Bridges, Wash.
(Who knew water would drop, say 2.5 feet in 25-ish minutes). Once off the mud on a rising tide, we limped to Anacortes for Rendezvous...and beer. (more on this below).
My questions:
1. What's going on (chemically speaking) on the outside of this pencil zinc? (Attached pic of white material on 11mm hex-head)
2. How can one diagnose a cooling system with corroded zinc (pic) like one can of combustion with a used outboard spark plug?
I've looked through E-archives, and found great stuff! A sampling:
What's a heat exchanger and its different metals, etc? (by MainSail in 2009, suggested by @Christian W.):
Thread 'Heat Exchangers A Closer Look' https://ericsonyachts.org/ie/threads/heat-exchangers-a-closer-look.7015/
Simpsons: "A World without Zinc"
BoatUS: "How Do Sacrificial Anodes Work?"
www.boatus.com
@kiwisailor brilliant but seemingly unappreciated suggestion to use "Barancle Buster" to flush raw water system or DIY soak Hx:
Post in thread 'Heat exchanger vs. pencil zinc. Assumptions and questions' https://ericsonyachts.org/ie/thread...c-assumptions-and-questions.18957/post-146623
Watch (incredible) Barancle Buster work:
@Christian's Big Picture: cooling system and Hx...
Thread 'Marine Diesel Cooling System Upgrade 2020' https://ericsonyachts.org/ie/threads/marine-diesel-cooling-system-upgrade-2020.17240/
My personal conclusions:
a. Save my nail polish for my toes and allow as much zinc to be exposed...just change zinc every 6, 8, etc months for your conditions...sooner if changing environments.
b. Check more frequently than.I think I ought to.
c. Save my Teflon tape for PVC cause electrons NEED metal-to-metal contact between anode and cathode.
To close... an A.I. subject joke:
"Why did the zinc break up with the copper?
Because the zinc was used as a sacrificial anode and was too negative about the current state of their relationship!"
What is the makeup of.the white stuff...forgot to taste it! Argh.
The timing of recent heat exchanger (Hx) discussion relating to broken pencil zincs forcing sailors aground...(oh, wait, that was our summer story.)
Well... yes, broken pencil zinc(s) blocked our Hx and blockage in raw water system significantly increased our engine's temperature enough to find local dock in Swinomish Channel at Twin Bridges, Wash.
(Who knew water would drop, say 2.5 feet in 25-ish minutes). Once off the mud on a rising tide, we limped to Anacortes for Rendezvous...and beer. (more on this below).
My questions:
1. What's going on (chemically speaking) on the outside of this pencil zinc? (Attached pic of white material on 11mm hex-head)
2. How can one diagnose a cooling system with corroded zinc (pic) like one can of combustion with a used outboard spark plug?
I've looked through E-archives, and found great stuff! A sampling:
What's a heat exchanger and its different metals, etc? (by MainSail in 2009, suggested by @Christian W.):
Thread 'Heat Exchangers A Closer Look' https://ericsonyachts.org/ie/threads/heat-exchangers-a-closer-look.7015/
Simpsons: "A World without Zinc"
BoatUS: "How Do Sacrificial Anodes Work?"
How Do Sacrificial Anodes Work?
The way to counteract galvanic corrosion is to add a third metal into the circuit, a sacrificial anode, and often that is zinc.
@kiwisailor brilliant but seemingly unappreciated suggestion to use "Barancle Buster" to flush raw water system or DIY soak Hx:
Post in thread 'Heat exchanger vs. pencil zinc. Assumptions and questions' https://ericsonyachts.org/ie/thread...c-assumptions-and-questions.18957/post-146623
Watch (incredible) Barancle Buster work:
@Christian's Big Picture: cooling system and Hx...
Thread 'Marine Diesel Cooling System Upgrade 2020' https://ericsonyachts.org/ie/threads/marine-diesel-cooling-system-upgrade-2020.17240/
My personal conclusions:
a. Save my nail polish for my toes and allow as much zinc to be exposed...just change zinc every 6, 8, etc months for your conditions...sooner if changing environments.
b. Check more frequently than.I think I ought to.
c. Save my Teflon tape for PVC cause electrons NEED metal-to-metal contact between anode and cathode.
To close... an A.I. subject joke:
"Why did the zinc break up with the copper?
Because the zinc was used as a sacrificial anode and was too negative about the current state of their relationship!"
What is the makeup of.the white stuff...forgot to taste it! Argh.
Attachments
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