# carbon assembly paste for alloy seatpost in carbon frame



## fah35 (Sep 17, 2004)

I know when you use a carbon seatpost it is recommended to use the carbon assembly paste on a carbon frame. What are you suppose to use with an aluminum seatpost and a carbon frame? Do I use regular grease or the carbon prep?


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## FBinNY (Jan 24, 2009)

Use the carbon prep especially if it also improves grip. Two problems with carbon/aluminum assemblies (doesn't matter which way) are gripping power, and corrosion. Chemicals in the Carbon matrix will attack the aluminum causing seizing, or simply eating it away. 

BTW- get in the habit of removing and inspecting the post once a year or so. You can slip a hose clamp over it as a depth stop to quickly return it to the original height.


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## fah35 (Sep 17, 2004)

What is the correct way to use the carbon prep on an alloy seatpost. I have heard a couple of ways. One is to put a thin apllication on the seatpost and put a dab inside the frame and the other was just to put a dab in the frame and put the seatpost dry. Is there any difference on how I apply it?


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## FBinNY (Jan 24, 2009)

It doesn't matter which as long as you make sure it's spread and covers the entire overlapped area to prevent corrosion. For traction alone, only the 2" or so near the pinch bolt make any difference.

Whether it's grease or assembly paste I prefer to spread it around the upper section of the tube, and let the post carry it deeper. It's less clean up that way.


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## Mel Erickson (Feb 3, 2004)

FBinNY said:


> Use the carbon prep especially if it also improves grip. Two problems with carbon/aluminum assemblies (doesn't matter which way) are gripping power, and corrosion. Chemicals in the Carbon matrix will attack the aluminum causing seizing, or simply eating it away.
> 
> BTW- get in the habit of removing and inspecting the post once a year or so. You can slip a hose clamp over it as a depth stop to quickly return it to the original height.


It's not chemicals in the carbon composite, it's galvanic corrosion, an electrolytic reaction, between the carbon and aluminum.


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