This weekend I finally got around to trying to repair my damaged carbon road bike- a Planet X RT-57 full carbon bike I got under the bike to work scheme in 2012, as obviously none of my other bikes were suitable to coast the half mile down the road every day.
Tragically it fell over in the garage in 2013, and the top tube impacted right on the pointy corner of a concrete step- ouch.
I lost confidence in it on the road after that, as the area of damage could be deformed by thumb pressure. And the tap test with a coin showed that part as a dead spot.
But last year I looked into carbon fibre frame repair, and found it was pretty viable, and if you have ever built a stitch and glue boat before, pretty familiar. So I got a kit from Easy Composites, which included the all important heat shrink tape to squeeze out excess epoxy from the carbon fibre weave.
And did nothing with it for another year.
But at the weekend I sprang into action. I sanded down the area where I had decided to triple wrap the tube with a patch that tapers for each successive layer, then masked it off and coated it with a layer of epoxy, and left it 4 hours to get tacky:
The patch was templated in advance, and looked like the following. The tube profile is a tapering rounded triangle, so there is a small turn for each layer.
You'll detect a bathroom vibe in these pictures- I did most of the work in our upstairs bathroom as I needed to keep the temperature about 20C for the epoxy to cure.
Applying the patch, wrapping it around the tube and wetting with epoxy, then wrapping with heat shrink tape which is shrunk by gently using a heat gun, and mopping up the excess epoxy got me to here:
This was left to cure for another 6 hours and the tape removed to show something that looked like what I'd seen on the YouTube videos.
The kit contains 6 different grades of sandpaper, plus polishing compound, so I set to work to get a gloss finish. I was a bit disappointed with the polishing compound until I discovered I should have been using a wooly disc at 800rpm to buff it up rather than a vigorously wiped Tesco kitchen towel. Armed with this information and not having a wooly disc I vigorously wiped some more, and have now got to here, where it all sounds good tap test wise.
How to finish it? History tells me I will make an arse of painting, so I am minded to maybe just mask the transitions with a red stripe and clear coat it.
Carbon fibre frame repair by
Steven Heddle, on Flickr
Any advice gratefully received. Well, politely received at least.
Cheers
Steven
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