Frame repair / bonding

Hi

I fell in love with this NOS Specialized Allez Carbon frame a while ago and decided to build it up with new components. After a fantastic few months riding (lovely ride) i went over a ledge on it (don't ask) and the carbon downtube came apart from the alloy lug.

The carbon is fine (no cracks), it's just the bonding that gave up. Does anyone have any idea if or how i can fix this? I love the ride too much to give it up.

I've tried (rather optimistically perhaps) to glue it with Araldite (epoxy resin) but didn't have enough surface available to make it effective without pulling out the tube too much.

Any ideas would be much appreciated.

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I really hope araldite didn't ruin the resin in the carbon.... If it didn't, it can probably be rebonded though it'll cost. I'd give the guys at CarbonRepair.com a shout, can't hurt to call them and ask their advice. Also on retrobike I saw a thread a couple of years ago about rebonding the Raleigh Dynatech frames, they also might be worth a thread/shout as there's plenty of lugged carbon lovers there.

Thanks Citygent, as I said any help appreciated.
Carbon fiber fine after araldite. My research led be to beleive thos frames were bonded with epoxy originaly.
Will try those. Any experience with carbonrepair.com?

Not personally but I've had a customer of my store use them for a crack, said they were difficult to get hold of but very knowledgable and professional.

Shoot Stonehedge a PM, I believe he is in the middle of or has just finished getting a carbon frame repaired so his advice would be worth getting.

I had this fault with a Peugeot PY10 FC (Vitus). I used some 3M adhesive but it eventually broke again.

I used a ratchet strap to pull the frame open to access the lug. You also need to clean the surface thoroughly. The adhesive must have a very high peel strength.

Personally, I'd sell or bin the frame. It's not nice riding something that might potentially break more easily during use.

Get some 24 hour epoxy and some microballoons (you can get these from a good modelshop)
Mix into a paste and leave for a couple of days till fully cured,I've used this method of bonding
on r/c gliders for 20+ years with no problems

Get some 24 hour epoxy and some microballoons

Like balloons for ants?! Cool!

Very nice frame (got a similar one). Due to the frame beeing almost 20 years old now and fear of it breaking apart I recently retired it

I remember a guy writing in a forum that specialized themselves advised to use these frames for no longer then 8 years...

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once glued you might try pinning it too (prepare holes before gluing) - this will hep it stay together when curing too - if you do it quickly enough after gluing.

• a bolt or 2 will work but drill and tap the lug (and the carbon) and put in grub screws and it'll be a flush job -you could even sink them in a little and cover them with something to hide them. (that depends on how long is the lug and how thick are the lug walls ?)
  
  

not as sightly but - alternatively - or as well as the above - fit some sort of cir clip around the tube (you may need to make tiny slits -like this http://www.sjscycles.co.uk/use-seat-post-shim-272-mm-id-prod22922/ - in the carbon end so it'll clamp onto the lug instead of just compressing and cracking the carbon )

once glued you might try pinning it too (prepare holes before gluing) - this will hep it stay together when curing too - if you do it quickly enough after gluing.

I like this idea. Smothering a pin/bolt/rivet with epoxy might really help it to hold.

The problem with this particular joint is the massive strain it goes under when you sprint or get out of the saddle; you're thrashing your legs down like you're trying to pull the frame apart. Unfortunately, that is what happened to me.

I thought Carbon fibre was very bad at dealing with point loads, that's why I've avoided the pin/bolt method so far. But the outer shim idea is a good one, need to measure my tubes. One of my colleagues, a techie guys, suggested super glue on the inside and wrapping strip soaked in epoxy on the outside. Could end up looking like I'm ridding Frankenstein's Monster's bicycle, but then again, I often look like Frankeinstein's Monster anyway.

Metriod - nice bike. How can you retire such a beaut? Or have you acquired a much fancier steed?

Wyrmskull - Microballoons are used for filler right, no strength properties?

Microballoons are microscopic spheres of glass so when mixed with epoxy it effectively
becomes fibreglass,i would be tempted to wrap 2/3 layers of thin carbon cloth soaked in epoxy around the joint for belt and braces
Dont be tempted to use screws and the like,They will just cause the carbon to splinter over time, you could drill straight through the tube and lug and fit some solid fibreglass rod (b+q used to sell it)Say 3 or 4mm dia