Bubbling on bonded aluminum lugs

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Bubbling on bonded aluminum lugs

Author	Message
erikrhendrickson	erikrhendrickson posted 12 Years Ago HOT Topic Details
Group: Forum Members Posts: 3, Visits: 3	Hey Everyone, Thanks in advance for your time. Been restoring a 1987 Trek 2500 with full Dura-Ace for my brother's birthday. The carbon tubes has some bubbling near the lugs just under the clear coat. I have the clear sanded off now down to the fibers...was careful not to bite into them. Do you think this is repairable? What kind of clear coat should i use...lacquer or enamel? Any specific recommendations? Thanks, Erik
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carbonfibreworks	carbonfibreworks posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 292, Visits: 4.5K	Hello Looking at the image it appears that the carbon tubes have increased slightly in diameter where they go over the alloy sections, check with a micrometer and if this is the case for safety reasons do not use the frame. If moisture has made its way between the alloy and carbon corrosion will take place increasing the diameter of the alloy and possibly causing the discolouration you seen in the carbon tube. Donate the frame to a school or college i am sure they can use it in the engineering/materials dept. Chris www.carbonfibreworks.co.uk Edited 12 Years Ago by carbonfibreworks
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Warren (Staff)	Warren (Staff) posted 12 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	does sound like moisture penetration and some nasty galvonic corrosion going on. Problem is if the aluminium has expanded much then the tubes may well have serious structural cracks along thier length. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant Edited 12 Years Ago by Warren (Staff)
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erikrhendrickson	erikrhendrickson posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 3, Visits: 3	No cracks or any other signs of wear along the tubes...just the ends near the lugs.
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Warren (Staff)	Warren (Staff) posted 12 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	Its what you can't see that worries me!! Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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FLD	FLD posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Whilst galvanic corrosion is unlikely for this (no dissimilar metals) it is possible that water has gotten into the joints and the aluminium has corroded. Aluminium oxide is something like ten times the size of aluminium. This could essentially burst the carbon tubes which have very little give. The marks come from the damage to the laminate. I think its one of those ride at your own risk jobs I'm afraid. Edited 12 Years Ago by FLD
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Dravis	Dravis posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 592, Visits: 1.9K	Just saw this thread, while scouting through old ones ... Yeahh Im Bored .... The "damage you are seeing in the Carbon ends of the tubes looks VERY much like the resin has been damaged by too much UV light.. It would make sense, since the Aluminium has probably been polished many times, and the ends of the tubes have had a part of the protective clear coat worn away. This is a death sentence for the CF tubes I'm afraid ... they will loose a significant part of their strength. But ... all is not lost, just make new tubes for the nice joints ... should not be too hard a job, if they are round tubes, you can just buy them and reinforce them as needed.. ... Good Luck.... "Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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