No carbon paste, what else?
05-12-11 | 02:11 PM
#26
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From: Minnesota
Bikes: N+1=5
https://www.parktool.com/blog/repair-...osts-and-stems
this is what i was thinking of...from the second paragraph in the link above:
"When inserting an aluminum post into a carbon frame, it is important to apply a barrier between the two surfaces. This is also true when installing a carbon post into a steel or aluminum frame. A 'galvanic reaction' occurs between the two different materials and this acts to eventually bond the post to the frame. Use a light coating of grease, anti-seize, or other lubricant to create a barrier between the two surfaces."
i guess i was mistaken in the sense that carbon paste is more for friction (and maybe just for carbon on carbon??), but it seems like the important thing is to get something in there to prevent bonding.
this is what i was thinking of...from the second paragraph in the link above:
"When inserting an aluminum post into a carbon frame, it is important to apply a barrier between the two surfaces. This is also true when installing a carbon post into a steel or aluminum frame. A 'galvanic reaction' occurs between the two different materials and this acts to eventually bond the post to the frame. Use a light coating of grease, anti-seize, or other lubricant to create a barrier between the two surfaces."
i guess i was mistaken in the sense that carbon paste is more for friction (and maybe just for carbon on carbon??), but it seems like the important thing is to get something in there to prevent bonding.
J.
05-12-11 | 04:52 PM
#27
My LBS told me to put a bit of grease around the top of the post to seal out water. The post itself was dry. I mostly did keep the top sealed, and didn't ride in wet conditions very often, but it didn't prevent the corrosion.
05-12-11 | 05:05 PM
#28
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From: Mountain View, CA
Bikes: 2012 Scott CR1 Comp
Nope, perfectly clean in there. The carbon paste appears to have stopped the slippage. Perhaps I don't have to apply a GI Joe kung-fu grip when tightening the seatpost clamp now.
05-12-11 | 08:17 PM
#30
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From: New England
Bikes: 2010 Jamis Xenith Comp
i'm just posting this because i find it interesting...i realize we're way past the OP's question. from Boeing (who, i assume, know what they're talking about):
"Fiber-reinforced plastics are corrosion resistant, but plastics reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structure."
https://www.boeing.com/commercial/aer...7/corrosn.html
you learn something new every day.
"Fiber-reinforced plastics are corrosion resistant, but plastics reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structure."
https://www.boeing.com/commercial/aer...7/corrosn.html
you learn something new every day.
05-12-11 | 09:14 PM
#31
Senior Member
Joined: Feb 2011
Posts: 4,681
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From: Minnesota
Bikes: N+1=5
i'm just posting this because i find it interesting...i realize we're way past the OP's question. from Boeing (who, i assume, know what they're talking about):
"Fiber-reinforced plastics are corrosion resistant, but plastics reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structure."
https://www.boeing.com/commercial/aer...7/corrosn.html
you learn something new every day.
"Fiber-reinforced plastics are corrosion resistant, but plastics reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structure."
https://www.boeing.com/commercial/aer...7/corrosn.html
you learn something new every day.
J.
05-12-11 | 10:19 PM
#32
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From: Los Angeles
Bikes: 1998 Land Shark 853, Ibis Bow-Ti
Yup. Friend of mine had a Specialized Epic from the early/mid-90s that was carbon tubes with aluminum(?) lugs. It eventually disintegrated where the two materials met. It's very important to isolate the two materials by adding something like a layer of fiberglass between the carbon and the metal (when building a frame). I think Specialized started doing that partway through the production cycle for that bike.
I'm not sure if any of the people making carbon posts go to the trouble of adding this "passivating" layer, so it is a good idea to regularly remove and re-grease a post that is being used in an aluminum or steel frame. The problem is worse if you live near the ocean vs. inland and worse if you ride during the winter in parts of the country that use salt on the roads. This is not a problem for titanium frames as carbon and titanium are adjacent in a published galvanic series in sea water [Jones, Principles and Prevention of Corrosion].
I'm not sure if any of the people making carbon posts go to the trouble of adding this "passivating" layer, so it is a good idea to regularly remove and re-grease a post that is being used in an aluminum or steel frame. The problem is worse if you live near the ocean vs. inland and worse if you ride during the winter in parts of the country that use salt on the roads. This is not a problem for titanium frames as carbon and titanium are adjacent in a published galvanic series in sea water [Jones, Principles and Prevention of Corrosion].
05-13-11 | 04:53 AM
#33
ka maté ka maté ka ora
Joined: Oct 2008
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From: wessex
Bikes: breezer venturi - red novo bosberg - red, pedal force cg1 - red, neuvation f-100 - da, devinci phantom - xt, miele piste - miche/campy, bianchi reparto corse sbx, concorde squadra tsx - da, miele team issue sl - ultegra
pipe compound is a thread sealant with teflon. inappropriate. get off your couch and get some carbon assembly paste.
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