Galvanic corrosion when using copper anti-seize on alu?
03-23-19 | 10:24 AM
#2
Senior Member
Joined: Jul 2014
Posts: 2,250
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From: Central Indiana
I use whatever is at hand but I'm no machinist.
https://www.practicalmachinist.com/v...mpound-184595/
This is a good all purpose choice:
Permatex
https://www.practicalmachinist.com/v...mpound-184595/
This is a good all purpose choice:
Permatex
03-23-19 | 10:34 AM
#3
Occam's Rotor
Joined: Jul 2013
Posts: 7,248
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The copper reduction potential is +0.34 V. The oxidation potential for aluminum is +1.66 V. The net standard-state galvanic potential is thus +2.00 V. So you will have a pretty good battery.
I'm sure Hope Hicks has the definitive opinion.
is this just another case where theory and reality are out of touch.
03-23-19 | 01:14 PM
#4
Banned
Joined: Jun 2010
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From: NW,Oregon Coast
Bikes: 8
"best" galvanic combination is carbon and zinc... Stacked, alternating , is a dry cell battery..
steel frames with aluminum seat posts and stems left in too long ,
is a popular theme for 'how do i get it out?', request thread topics..
aluminum in aluminum should not be an issue
add some silicone caulk to seal the top edge, if really worried..
...
steel frames with aluminum seat posts and stems left in too long ,
is a popular theme for 'how do i get it out?', request thread topics..
aluminum in aluminum should not be an issue
add some silicone caulk to seal the top edge, if really worried..
...
Last edited by fietsbob; 03-23-19 at 03:42 PM.
03-23-19 | 03:06 PM
#5
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Joined: Sep 2010
Posts: 8,327
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From: Roswell, GA
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
I use Tef-Gel on all dissimilar metal joints such as BBs, pedal threads, etc. Itcontains 40% PTFE powder and is specifically intended to resist electrolytic corrosion under marine conditions: https://www.tefgel.com/contain.php?param=tefgel_infor A little goes a long way.
03-23-19 | 03:34 PM
#6
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Joined: Oct 2014
Posts: 14,191
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From: Portland, OR
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
So I just recently heard about something called galvanic corrosion. Supposedly, this can occur between copper and aluminium when a catalyst (salt water) is present.
I am planning to use copper grease in my current build between aluminum components, some of which will experience salty conditions on the road.
Have any of you experienced any corrosion of this kind or is this just another case where theory and reality are out of touch.
Should I consider alu/graphite anti-seize, or is there nothing to worry about?
Thanks in advance.
Kret
I am planning to use copper grease in my current build between aluminum components, some of which will experience salty conditions on the road.
Have any of you experienced any corrosion of this kind or is this just another case where theory and reality are out of touch.
Should I consider alu/graphite anti-seize, or is there nothing to worry about?
Thanks in advance.
Kret
Ben
03-23-19 | 05:06 PM
#7
Senior Member
Joined: Aug 2015
Posts: 2,332
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Im not intimately familiar with these products, but several manufacturers specifically recommends zinc based anti seize for aluminium joints.
https://www.henkel-adhesives.com/jp/...e_lb_8044.html
I just use grease and it has been perfectly adequate.
https://www.henkel-adhesives.com/jp/...e_lb_8044.html
I just use grease and it has been perfectly adequate.
03-23-19 | 08:06 PM
#10
Senior Member
Joined: Mar 2018
Posts: 121
Likes: 2
From: Indiana
Bikes: Felt Z5, Look 675 Light, Specialized Diverge
I've switched to using this for all my anti-seize applications and have been very happy with it. It has no metal or conductive content so you get no galvanic action at all:
https://www.amazon.com/Permatex-2412...JGTV8XRPSXE1Q0
https://www.amazon.com/Permatex-2412...JGTV8XRPSXE1Q0
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