Sure, I will share but get ready for some internet shaming...
It's nothing more than a water-activated carbon fiber repair patch. They are used in various applications and comes in different brands, formats or versions, from expensive to cheap. You can easily purchase them online.
https://m-source.com/3m-tm-armorcast...ral-24795.html
https://www.amazon.com/FiberWeld-Per...dp/B08B3MKWH9/
Video
https://www.youtube.com/watch?v=A80s23lAJzY
https://www.youtube.com/shorts/2WZL3KvLcxI
https://dod.defense.gov/OIR/gallery/igphoto/2001915296/
Very easy to apply. Just soak in water to activate the resin, wrap it around the repair area, several layers overlapping, let it dry completely, wait at least 24 hrs. Before I wrap, I actually put another layer of quick setting epoxy over the crack, the ones that you have to mix in equal parts with a hardener. I do that to prevent any further fraying of the exposed fiber. I wore a latex glove and tried to rub the epoxy into the little nooks and crannies, not sure if that will help with anything but certainly no harm.
You will read warnings everywhere, considered an emergency repair, not a permanent fix, not safe long term.
I chose this method of repair for its easy application, after assessing the location of the damaged area, the extent of the damage, cost/benefit/risk analysis, don't care about the aesthetics etc. It's a fun experiment. What do I have to lose, it's heading towards the landfill anyway.
The bike is a 2018-2021 Cannondale Synapse Carbon. I got it from my local co-op free of charge, brought it home so I can tinker with it. Upon further inspection, other than the cracked top tube, the whole frame looks brand new and in excellent shape. It's got pretty good reviews too.
https://bikerumor.com/review-cannond...t-all-rounder/
I contacted Ruckus Composites Repair and they quoted the following repair estimate which I thought was very reasonable and probably worth it.
Unpainted - Raw Carbon Repair - $450
Repair the top tube, leaving the repaired area crisp, clean, and unpainted
One week turnaround time (approx.)
Transferable lifetime warranty
Painted - Repair and Restore - $850
Repair the top tube, then repaint the repaired area to the factory color
2-3 week turnaround time (approx.)
Transferable lifetime warranty
I decided to try a repair on my own first. The fiber after it's cured is very strong and well bonded, I would say super solid, it's not going anywhere. I have actually ridden the bike a few times around the neighborhood, a couple of jumps and up down the curb sort of thing, so far so good, don't worry, I have very good dental insurance and I will be monitoring closely.
Again, here's the usual disclaimer: if you are watching this on TV, you are not superman, don't try and jump out the window. You can't actually fly.