K2 / Proflex Riders Group
General => Tech Forum => Topic started by: Thunderchild on November 02, 2010, 11:51:37 am
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Finally getting ready to inject some epoxy into the space around the BB shell on my Oz. THere is a thread around here somewhere about my Oz and a picture in my gallery for those needing a refresher. The more I contemplated the process; the more doubts I have. What does the collective think about how well the epoxy will actually bond to the BB Shell. Surely it will support it, but can it secure the BB shell so it will not move vertically or horizontally(=chainring on front derailleur rub). Thoughts?
Thunderchild
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A refresher on the damage would be good. My limited memory doesn't bring up the signs or symptoms.
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I think my only concern would be in getting the epoxy into the caverty and around where it is needed. Hopefully it wont just run to the bottom of the frame or spill out of the gap.
Good luck
Chris
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I just wonder if you can get it straight, and then keep it from rotating when cured.
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I used to do a bit (heavy irony) of epoxy bonding with Hexcel products. Clean, profiled surfaces and working well within the initial "sweat" time of the epoxy is critical. Do dry runs to speed the wet install. If possible, use vacuum bagging to fill all voids. Unfilled five minute or fifteen minute epoxy isn't the best stuff for a permanent fix. JB Weld is dandy for a lot of this kind of bonding. Just get the right formulation for the job.
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I used to do a bit (heavy irony) of epoxy bonding with Hexcel products. Clean, profiled surfaces and working well within the initial "sweat" time of the epoxy is critical. Do dry runs to speed the wet install. If possible, use vacuum bagging to fill all voids. Unfilled five minute or fifteen minute epoxy isn't the best stuff for a permanent fix. JB Weld is dandy for a lot of this kind of bonding. Just get the right formulation for the job.
Man I hate JB weld because I get a lot of repairs that peeps have tried to epoxy. I make the customer completely remove it before I will work on them.
But I have to say I do use it myself, and it works preetty good. :o :o
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I have looked at several loctite epoxies. Local rep was going to let me have some at cost...$50 :o I am going to use epoxy from our autoshop that has atleast an hour cure time to make sure it flows into the space around the BB shell. Same epoxy I used on my seatpost tube insert. I will post a few pictures when I drill the holes. I am going to try and borrow a boroscope and look inside after I drill the holes. I will try to take pictures, but last time I tried this on the boroscope screen the pictures were useless.
Thunderchild
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Good Luck!
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From the sound of your posts, you have it right. It's all about the preparation.
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Hi there
Been a while.
I hatched a similar plan, I don’t quite understand where you’re drilling if you hope to see something inside.
I was going to drill 3 or 4 x 3mm holes around the immediate vicinity of the insert, hoping to hit aluminium just inside the carbon skin.
I had even bought a whole load of 3ml syringes whose ends are a nice tight fit in the hole.
The small diameter of the syringe would enable me to inject the glue into the hairline gap at a decent pressure to ensure spread.
I intended to rinse with acetone under pressure using the same syringes before gluing.
One thing is sure, just sloshing glue around the parts isn’t going to hold much, it needs to be in a gap in such a way that the glue is only solicited in shear.
I have a tube of scotchweld DP480 that I’ve been keeping for the job; VERY good glue.
That was the plan, and probably still could be.
But since I drowned the gap in super glue on both sides I haven’t had any squeaks or movement.
Admittedly I’ve really been prevented from riding this last year; I’ve probably only covered around 1500 km since I glued it; but that is in the French Alps, so it’s pretty intense ;-)
Good luck with your gluing
Luke
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Luke!
Great to hear from you. I have been delayed on my Oz project and your super glue technique might be worth a go. Can you describe in detail how you got the super glue into the BB/frame separation?
Thanks
Thundechild
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just nice to see some familiar "faces" still here!