Hey does anyone have any experience in repairing a small crack in carbon fiber frames about 1-1.5cm long?
It is on the Top Tube on top and in the middle, somebody fell over and the bars hit the ground, presssing on the side of the frame.
Clear as mud?
Any help would be greatly appreciated.
Tarp
Your best bet is to check with one of your local retailers that sells composite materials…or a aircraft repair facility if you have one near by as they use lots of carbon fibre usualy…they can tell you who to visit and/ or what to use…
the big disadvantage of carbon - once it’s bend (compressed fiber etc) or cracked (fibers sticking out) the structural integrity is compromised and you cannot repair it - you can only toss it out
check with a honest bike shop or the manufacturer of the frame just in case (send them a picture of the damage)
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Great, it is brand new, and there are no aegis dealers around.
I need to vomit!
The middle of the toptube is not under much load and carbon fiber is repairable. Can you post of picture of the damage?
If you have a crack that appears to need support. I would use a 1 inch strip of carbon and wrap the toptube at the point of damage.
Just to give you a data point… my carbon Trek mountain bike has chips and small impact marks from rocks and crashes. I just fill them with a bit of West System Resin. The frame is about 4 years old and it seems to work fine.
I will get a pic later.
Thanks
Tarp
carbon is infinitely repairable and actually pretty easy to do. It may not look perfect, but it is fairly easy to repair, like fiberglass and you can build it up stronger than new with little effort and limited visual imparement.
If you can’t get a vendor guarantee, just find some carbon woven tape, 1" or so, and use West System epoxy. Small boat dealers or a boat chandlery (hardware store) will carry the West and maybe some fiber. Clean and lightly sand the borken part, mix up the epoxy wet out the tape and wrap it up. I would also wrap the wet “lay-up” tightly in saran wrap to make the outside smoother. It takes a short time to do (10 minutes) and cure (~2 hours to the touch), so you can practice on a broomstick first to teach your how much of everything to put in and to do and show you how easy it is to drip or make look good. Get yourself some latex painting gloves so you don’t have to wash up.
See http://www.westsystem.com/ for info. on how to fix it and http://www.jamestowndistributors.com/index.asp can sell you the West and carbon fiber online.
Dude Thanks! I will fix it!
Tarp out!
Thanks from me too! I actually have a boat that needs some fiberglass repair.
-jeff
cool, one other thing to note: the less epoxy, the better. The epoxy is just the bonding agent for the fibers, which are the strength. So resist the temptation to goop it on the fiber. Just use enough to get everything completely wet. They actually squeege the tape prior to wrapping: Layout the dry tape on wax paper (after trying a few test wraps with it dry to see how it’ll go on) drip the mixed up epoxy on the tape (use a disposable plastic “go cup” and a thin/electrician’s screw driver for mixing, you can clean/chip off the screwdriver when you are done.) the epoxy will be "workable for about 20 minutes, unless you mix in too much hardner, then it will “kick” quicker (and get hot as the chemicals react) smooth/push the epoxy around to get the tape completely soaked Push any over-saturation off the tape and onto the wax paper so it doesn’t stay with the tape. You can use your gloved finger or a small piece of plastic to act as a squeegee Pick up the tape off the paper and wrap it around the break Wrap plastic wrap around the fix to make it smooth Try to avoid sanding after the fix because that might tear the fibers, which are the strength. Again, use disposable latex gloves ($6/100 at Home Depot) put some newspaper on the downtube to catch and drips in the process not sure the layup on a bike (you should ask a bike designer for that, and maybe what is the best cfiber to use from them or the place you buy the c) and the size of your crack, but I would guess that 2 wraps/layers would do it. It will bulge a bit, but just put a Budweiser or Maxim sticker over it when you are done and it will look custom
West System epoxy as someone else here noted. Less is more with carbon. Aircraft Spruce (aircraftspruce.com) or Johnson Marine sells carbon plus other carbon supplies (like peel-ply which you’d want to use to keep the fiber pushed down and to bleed out extra epoxy). That being said, you may only need a bit of epoxy to do this repair. Post a pic. There are lots of people with lots of experience in carbon on this forum…