K2 / Proflex Riders Group

General => Tech Forum => Topic started by: Matno on February 21, 2003, 01:57:04 pm

Title: Hey! You CAN fix broken carbon fiber!
Post by: Matno on February 21, 2003, 01:57:04 pm
At least, according to this auction you can...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2712569973&category=22679

Is this guy for real? Now I know that if I ever break my swingarm, I can just sell the frame for $300 and buy a new one... ;)
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: IFO on February 21, 2003, 02:21:19 pm
ummm not....

it can be repaired to a point, but not enuf to still be sellable.. esp. not for 300$US...
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: 5500C on February 21, 2003, 02:49:44 pm
Quote
At least, according to this auction you can...
[url]http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2712569973&category=22679[/url]

Is this guy for real? Now I know that if I ever break my swingarm, I can just sell the frame for $300 and buy a new one... ;)


If someone buys that frame and believes that you can fix it, I've got a unsuspended Huffy that rides as smooth as an OZ!!!
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Irby on February 22, 2003, 12:01:49 am
There is a sucker born every minute.
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Dennis on February 22, 2003, 09:18:53 am
hey, wait a minute. you CAN fix carbon fiber. did anyone see the all carbon America's Cup yacht that broke in half about 3 years ago and allmost sank?
well, they fixed it, and it was faster after the repair then before.
also. plenty of those boats were rebuilt this year. they replaced 40 feet of the bow on several of the boats. and on the 41 footer I sail on (kevlar, not carbon but similar repair), we had a huge hole in the side from a collision, and it was repaired. If they can fix broken 80 foot carbon sailboats I think someone can fix a broken swingarm. take it to a carbon boatbuilder, not cheap probably, but doable.
oh, and broken Trek and Kestrel carbon frames are fixed all the time.
please don't flame me on this one, I know I am putting myself up for ridicule but what I say is true. In fact., back when I was a mech. engineer, a couple carbon structures used to support radomes on Navy frigates cracked at sea, and were repaired at sea. When the ships returned, the structures were as strong as new. truth.
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: w2zero on February 22, 2003, 12:37:36 pm
Very likely that is cf and thermoplastic matrix.  Not repairable.  If it were thermoset cf epoxy then it could be repaired, maybe.
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Mr.Ed on February 22, 2003, 01:45:04 pm
wow    simply amazing.... exactly from what height was this frame dropped, I wonder????  and the bottom trailing arms , he cant fit on???  this is a bike shop??     what a deal   [smiley=laughing.gif]

I cant say how many times my OZ and I went different directions on the trail, unattached. It hasn't broke yet. I always break first.  
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: 5500C on February 22, 2003, 02:48:18 pm
Quote
hey, wait a minute. you CAN fix carbon fiber. did anyone see the all carbon America's Cup yacht that broke in half about 3 years ago and allmost sank?
well, they fixed it, and it was faster after the repair then before.
also. plenty of those boats were rebuilt this year. they replaced 40 feet of the bow on several of the boats. and on the 41 footer I sail on (kevlar, not carbon but similar repair), we had a huge hole in the side from a collision, and it was repaired. If they can fix broken 80 foot carbon sailboats I think someone can fix a broken swingarm. take it to a carbon boatbuilder, not cheap probably, but doable.
oh, and broken Trek and Kestrel carbon frames are fixed all the time.
please don't flame me on this one, I know I am putting myself up for ridicule but what I say is true. In fact., back when I was a mech. engineer, a couple carbon structures used to support radomes on Navy frigates cracked at sea, and were repaired at sea. When the ships returned, the structures were as strong as new. truth.


When they repair these, don't they normally repair it from the inside making the ugly layering of materials "invisible"?  If they were to fixt hat, you would see some disgusting looking wrap around the swingarm.  

Maybe I'm wrong on this one, unless you can cut out the portion of the carbon fiber that was cracked and then re epoxy some sort of fix in there.  Wouldn't that change the flex characteristics overall?
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Vitaliy on February 22, 2003, 04:11:37 pm
I the guy selling it with reciept you might be able to replace it using the waranty, i'm not sure what  Schwinn  waranty, but if it's close to K2 (5 years for frame and swingarm) it might work.
Yeah about repairing it, maybe possible, but not permamently, i heard they using high temperatures and high presure forming those swingarms, and any quality carbon fiber frames, stems etc.

Just mine 2 pennies.

P.S. just got 2000 EVO 4.0 frame, building it now.




Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Vitaliy on February 22, 2003, 04:20:54 pm
I meant : "if the guy selling it with reciept, i'm not selling it, just typo,



sorry.

By the way what si the size for seat post for 2000 evo 4.0. is it 27.2?
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Matno on February 23, 2003, 10:34:27 am
Too bad Schwinn went bankrupt and isn't honoring their warranties past a year.

As for the seatpost, yes, it's 27.2mm. Have fun building that awesome frame!
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Dennis on February 23, 2003, 11:23:47 am
yes, it could be repaired. the fact that you can see the weave means the cf was laid up in sheet form into a mold. and  yes, it would look very ugly if you repaired from the outside since there is no inside as in a boat, but it could be done. I know at least one surfboard maker who could do it and it would be hard to tell that it was repaired.
of course, the problem is that you don't know how deep the crack goes.
on the boats, what they do is, they cut the bow or stern off, and then scarf ( a series of jagged cuts,like a lightning bolt) the new bow or stern on. the cf overlay is on both the inside and outside and it is faired in. the scarf is there to increase the bonding area.
Title: Re: Hey! You CAN fix broken carbon fiber!
Post by: Vitaliy on February 23, 2003, 12:56:16 pm
Thank you Matno , I hope I'll finish the bike by May, so  I can ride it this Summer.