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Noticed a couple of cracks on my old Cannondale frame yesterday:
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Old second hand frame of no value, another old frame in shed waiting to go - but I've grown fond of this one over the last 13 months. Not worth a 'proper' repair, but I'm toying with the idea of taking it round the local metal shop to see what they can do; quick'n'dirty, wouldn't need to look pretty, spray can the damaged paintwork afterwards. Not a critical tube join, the metal's quite thick there...
Anybody done something similar successfully?
I'd be tempted to just fit a jubilee clip round it to hold it in place. Welding Aluminium without subsequent heat treatment can weaken it further.
Slip a bit of inner tube over the clip to hide it!
I've seen successful repairs and also comments online that the heat treating is lost an dit won't work.
Yeah, I know all the theory and anecdotes, I was after actual experience. Might just try it and see for my own interest.
for balance - my son ran an alu Kona with a cracked/welded head tube with no issues but he was doing gentle xc.
Fiberfix!
After watching both videos on here I'd second Fiberfix if its not ££££
If it's not a 27.2mm seatpost I would be tempted to just bang a shim in there and run a smaller diameter seatpost.
There's a history. Nominal 31.6mm post size, but both 31.6 and 27.2 with a 31.6 shim slipped or creaked. Put in a 31.8 shim, no slip or creak. I'd leave the shim in if I went the fiberfix route.
I'd weld it, with synergic MIG,the metal there is relatively thick,easy to glen it out from behind after, plenty of strengthening in that area already, distortion is not going to be a problem
You'll never be able to sell the frame, so what you do to it now doesn't matter.
I suggest epoxying the seatpost in at your required height. If you cut off the cracked bit it will look neat, and you can tell everyone it's a weight weenie modification - especially if you remove the unnecessary length of the seatpost.
And think of the weight you get rid off by dispensing with the seat clamp... 🙂
Best of all, you only need £5 of epoxy, and no need for repaint or expensive craftmanship with a welder.
Why not drill the ends to stop crack propagation then bond the shim in?
Selling it was never going to be on the table. It's a 26" frame I bought off here for £60 and intended using to destruction, as I do with all my frames. Epoxy, you say...any particular kind?
nixie
Subscriber
Why not drill the ends to stop crack propagation then bond the shim in?
That seems like the best suggestion, in my opinion.
JB weld is a good choice as an epoxy adhesive
Get it welded, job done.
Cannondales are made using 6000 series, heat treated alloys - so welding will create localised embrittlement, plus the heat will blacken all the paint and make it look $hit. Drilling holes to prevent crack-propogation and bonding in a seat post - make sure you use a flap wheel or similar down the seat tube to prep the surface / improve the bond. I'd use a something like Devcon 2 Ton Epoxy which has slower cure time / good gap-filling properties.
Has anyone mentioned stickers yet