SailNet Community - View Single Post - How much zinc is enough?
View Single Post
  #7  
Old 10-15-2011
boatpoker's Avatar
boatpoker boatpoker is offline
Senior Member
 
Join Date: Jul 2008
Location: Toronto
Posts: 1,054
Thanks: 8
Thanked 25 Times in 24 Posts
Rep Power: 7
boatpoker is on a distinguished road
Quote:
Many people in the Marina also hang a clamp on "Grouper" zinc anode due to stray currents causing galvanic corrosion.
Stray current does not cause galvanic corrosion. Stray current corrosion and galvanic corrosion are two entirely different things.

Quote:
Yeah, you can over do it with anodes. They will react with the copper in the bottom paint. Foggy
Quote:
From what I've read it is possible to over do it with zincs. There has to be the correct amount of sacrificial anode to neutralize electrolysis. Too much will create current where it didn't exist before.
You cannot "over do it with anodes" No matter how many anodes you affix (if they are all of a kind) the voltage potential does not change. You can only over protect by using improper anodes (zinc, aluminum-indium, magnesium etc.) for the water the boat is in.

Electrolysis has nothing to do with it. Electrolysis is a chemical change in an electrolyte due to the passage of current.

Quote:
Yeah, you can over do it with anodes. They will react with the copper in the bottom paint.
Simple physics ..... there can be no electrolytic reaction without contact and anodes should not be in contact with bottom paint.

Quote:
They work although there are better methods to bond the shafts such as something like a wire brush or even a carbon electrode.
A carbon electrode will most certainly cause galvanic corrosion in stainless steel.

Petar : There is more mythology on this topic than anything else in boating and it an extremely complex issue. Either hire an ABYC Certified Corrosion Technologist or take the corrosion course yourself but take all dock walker advice with a grain of salt.
__________________
Dirt People Scare me

Last edited by boatpoker; 10-15-2011 at 09:16 PM. Reason: spelling
Reply With Quote Share with Facebook