RoadBikeReview.com's Forum Archives - General
How to fix a Colnago C40, again.(21 posts)
|How to fix a Colnago C40, again.||slow-ron|
Feb 19, 2002 5:29 AM
|I was so intrigued by the sale of this frame and the susequent bashing of the buyer that I contacted him through e-bay to ask how he intended to fix the bike.
Here's his response to my e-mail.
"My reason for going as high as I did on this frame was because I have actually repaired several other older vitus/specialized carbon tubed/aluminum lugged frames with excelent results. not a single one of those frames have failed since the repairs. I would remove the aluminum
lugs by heating them and then quickly freezing them. aluminum has a different expansion rate than carbon and that would cause the epoxy to break thus making removal very easy. then I would clean and re-prep the carbon tubes. I'd grind away between 1/3-1/4 of the aluminum lug so the
lug was now flush with the tube. then I'd wrap the aluminum with a single layer of fiberglass cloth to prevent galvanic corrosion. that's the reason the frames fail in the first place. then I'd laminate layer upon layer of wetted out carbon fiber fabric very much like how craig calfee
builds his bikes. only I instead of using big blocks I use a vacuum bagging process where an airtight bag is placed around the area, and all the air is sucked out. once all the air is out you have depending on the barometric pressure that day between 16-18psi pressing down over all the surfaces. not just the sides like in craig's process. and with over a square foot of actual surface area, you are talking about over 200 pounds of pressure. that squeezes out any remaining epoxy resin and you wind up with a super strong joint. this colnago will be my crown jewel. I really want to see how colnago makes their seamless carbon lugs. I might put pictures of it on the calfee owners forum."
If he's making this up he's sure got me fooled. I hope he enjoys the C40 as much as we've all enjoyed making fun of him.
Feb 19, 2002 5:52 AM
|Everyone knows you can't repair that frame yourself! It must be returned to Colnago in Italy! Who does this guy think he is?
Honestly, I wish him luck. My guess is that he will come through just fine. My only negative comment is how much he paid for the broken frame.
That Colnago brand is a very powerful aphrodisiac.
|Does this idiot know that ...||pmf1|
Feb 19, 2002 9:08 AM
|C-40 lugs are carbon, not aluminium. I'd like to be there when he heats them up. Actually, its very obvious that the lugs are carbon.|
|Does this idiot know that ...||Henrey T.|
Feb 19, 2002 9:30 AM
|Yeah, where did he get the idea that the C40 lugs were aluminum. I would pay to be a fly on the wall when he heats it up and waits for the epoxy to separate from the all carbon lug, what a sight indeed. LOL!|
|How do you know he's an idiot?||Nessism|
Feb 19, 2002 9:52 AM
|It sounds like this guy has gotten his hands dirty working on various carbon frames in the past. And he never said the Colnago has aluminum lugs, only that he has worked with aluminum lugged frames in the past.
The C40 appears to be made from premade carbon tubes bonded into carbon lugs. The lugs in the headtube area look to be on the outside of the tubes. It shouldn't be too hard to grind away the old lugs leaving the main tubes intact. After this, a new headtube assembly would need to be fabricated and attached to the old tubes.
Doable but time consuming.
|I don't even think its doable||pmf1|
Feb 19, 2002 10:06 AM
|The headtube itself is a lug. The top tube and the down tube stick into it. From the picture, it appears that the break occured at the part of the top tube that is lugged. Basically, the one-piece lug broke. You'd need a whole new head tube / lug to fix this. There is nothing left to insert the top tube into. The lug is broken. |
How will this bike end up looking? The guy needs a new fork (Colnago Star is $750), and a new seatpost (he has no choice, it will have to be the Colnago 28 mm post). So for $525 + $750 + $175 = $1450 (plus lots of screwing around on his part) he gets a C-40 which could be had on close-out for $2700.
I have no doubt that this guy will fix the bike somehow. I also have no doubt that I wouldn't ride it down a mountain pass for any amount of money.
|what if he buys another broken C-40?||mr_spin|
Feb 19, 2002 10:29 AM
|Aha, he may be a smart guy after all....
What if he comes across another broken C-40 where the headtube is fully intact? What if he already has one and this one was his second? He can grind out the good headtube to replace the bad.
I still wouldn't ride it.
|Why does he need a Star fork?||Nessism|
Feb 19, 2002 10:38 AM
|$750 for a fork sounds kind of spendy. I should think that some other brand would be serviceable for much less money. Not sure about the seatpost but I should think that some other brand would fit. No?
And yes, an entire headtube assembly will be necessary. I posted this link into a similar thread last week but it bears repeating.
If this guy can make an entire frame from scratch, why can't someone repair this Colnago?
I still say doable but this is predicated on the rest of the frame being undamaged. Big if.
|Why does he need a Star fork?||Looks my man looks|
Feb 19, 2002 12:20 PM
|One of the biggest attributes of the C40 is its looks and uniqueness. Riding around on a C40 with some other brand of fork would look strange, not cool to a true Colnago fan. Just MO. For $525 I think the guy either got hosed royally or he has money to burn and just likes tinkering around with stuff.|
|If you have to ask ...||pmf1|
Feb 19, 2002 1:46 PM
|Yeah, any one inch fork would work. Only one would look right though. |
As for seatposts, not too many choices in 28 mm. I suppose you could shim a 27.2, but then we get back to looks.
Lots of guys make entire steel or aluminium frame from scratch. A lot fewer can make them out of carbon fiber.
I'd love to see the results. Hey, I hope the guy can pull it off. I just don't see it being possible. I have one of these bikes and the break he has to deal with involves more than just a simple lug. I don't see how it can be fixed. I wouldn't trust it myself.
|why do you think he will keep colnago paintjob?||nm|
Feb 19, 2002 3:29 PM
|not sure about the seatpost...it's a weird size (nm)||sadsad|
Feb 19, 2002 3:29 PM
|Does this idiot know that ...||HautacamorBust|
Feb 19, 2002 9:53 AM
|That guy's post doesn't seem to make much sense. In his first 2 paragraphs he discusses how easy it is to remove aluminum lugs from the epoxy matric due to different thermal expansion properties, file them down and replace them. Then at the end of his message he states how anxious he is to see what the Colnago seamless carbon lugs look like so it sounds like he knows they are carbon so how is he gonna remove them??
Also, his entire repair theory appears predicated on the assumption that there is no further structural damage to either the downtube or toptube or even the headtube. He seems to assume that even the headtube is ok and that the repair involves only replacing the lug joint itself. I'd be very surprised if all 3 tubes didn't have some sort of internal fracture damage from an impact collision like that, CF simply doesn't do very well in impact collisions and the matrix which holds the carbon fibers cracks very easily from impact type collisions, this is well known. He might have just bought a $520 wall ornament but maybe he'll keep us informed on his progress, I'd be very interested to know how it ends up.
Feb 19, 2002 10:10 AM
|He said he knows the lugs are carbon||Tig|
Feb 19, 2002 10:16 AM
|"I really want to see how colnago makes their seamless carbon lugs." I still don't understand why he would pay so much just to see how Colnago make their lugs. That knowledge may be the only thing he comes away with!
If he does fix it, is there anyone here that cares to test ride it? Perhaps on a fast, twisty descent? Naaah, me neither!
|Does this idiot know that ...maybe he does||fuzzybunnies|
Feb 19, 2002 7:25 PM
|I was talking to a trek rep who had an entire 5500 frame that was unassembled so he could show how the frames were put together. According to him if the frame is heated to around 180 degrees the glue will soften and allow the frame to be pulled apart without damaging any of the carbon. Quite possibly he could pull this one apart and repair or replace the headtube. I wouldn't ride it after he's done but it doesn't mean it won't work. Russ|
|re: How to fix a Colnago C40, again.||STEELYeyed|
Feb 19, 2002 10:02 AM
|From the picture,it looks as though it is the CF top tube lug itself that is broken,and it looks as though the lug is part of the headtube.
If that is the case,then he is going to have to have a whole new headtube assembly or figure out a way to glue that top lug back on,assuming that he can get it separated from the frame. Of course we are all just speculating,but I love fixing things that others have discarded,sometimes it is just a matter of locating the parts and knowledge,which is this case are not going to be easy to come by.
|there's the catch.||slow-ron|
Feb 19, 2002 10:54 AM
|For most people on this board this project doesn't make any sense. But for some of us the challenge is fixing something that no one else would touch. Sure this bike may look like Frakenstein after he's done with it but if he survives the first hairpin turn and lives to tell about, I'm sure he'll have a sense of accomplishment.
I've got a rear derailleur on my wind trainer bike that I made from old pieces of Shimano, Sun-tour and Campy derailleurs. Thing shifts flawless. I could afford a new one but I had more fun making this one work. Maybe I can sell it to the C40 owner?
|I have enjoyed this, really.||calfeenated|
Feb 21, 2002 11:19 PM
|well, now that I have been sufficiently ridiculed on this site you might as well hear this from the source.
Why in the heck did I buy a cracked up c-40 for $526 off ebay? Well, my real motivation was to see how a $3,000 carbon frame fails in a crash and how to make sure that my carbon fiber recumbent doesn't do the same. I really have been trying to find a trashed carbonframes or calfee but I literally have been searching everywhere on the web for over a year and have not found a single one. I have never heard of one that failed at the joints. this c-40 will probably be a once in a lifetime opportunity for me to see first hand how one of these is put together. If all else fails, I may use the tubes to build into my recumbent.
my name is mark, I live in minnesota, I used to be a guitar maker/repair guy. I once fixed a completely demolished guitar headstock on a 60's guild that had been busted no less than 4 times and each time it had been repaired even worse. when I got it, it had been glued on for the last time with bondo. I repaired it with 3-7 layers of carbon fiber and epoxy. and it is still being played with no problems. I will try to post a picture of the colnago soon before I break it down to see how it's made.
I'l keep you posted. ps. everyone here that thinks I'm crazy needs to pay homage to damon rinard's site. Rinard Rocks!
Feb 22, 2002 2:37 AM
|Can you post a picture of your 'bent too?
Feb 23, 2002 11:00 PM
|I will. the recumbent is in the very early stages. it is a couple pieces of blue styrofoam being held together with some epoxy waiting to be carved into it's more final shape.
I got the idea from M5 recumbents. their site is at this url.
mine will bear a close resemblence to their carbon low racer but with a 24" rear wheel. the problem with their low racer is the length. it is too long to be raced on the american uscf circuit. uscf has a 2 meter limit on overall length. If I am going to devote 6 months and thousands of dollars to this I want to be able to at least test it at some local time trials. I am posting a picture of M5's carbon low racer just because it is soooooo cooool lookin, mine will look similar, mine will probably look like a cross between their cromoly low racer and their carbon one. mine will have large diameter carbon tubes but with a detachable seat mounted on elastomers that would allow about 3/4-1" of shock absorbtion. anyway, enjoy.