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BigJimmyB
Joined: 31 May 2008
Posts: 374
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 Posted Wed Nov 4, 2009 1:38 pm |
Wonder if anyone can help with this.
Suffered damage to the main part of my Scott Ransom carbon frame last week in CYB, to the point where it's likely to be a write-off.
As I'm not original owner, I have no warranty - recently confirmed by Kude bikes, who are waiting to hear from Scott on how much I'll need to pay for a new front triangle.
Anyway, I've been lucky enough to procure a ally Ransom 30 front triangle and may stick with this if the new carbon one proves too expensive (with twins on the way, much of my funds will be 'diverted'!).
What I'd like to do is strip the seat and chainstays to maker them a better match, colour-wise.
Will prob get the ally chainstays media blasted so they are back to 'raw' ally, but am not sure how to handle/prepare the carbon seatstays.
Can I just sand them back and paint them silver to match the rest? Anything I need to know, paint types to avoid? Can I use a paint-stripping chemical?
Grateful for any help/advice.
BJB
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BigJimmyB
Joined: 31 May 2008
Posts: 374
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Posted Wed Nov 4, 2009 1:43 pm |
May I have my answer here, but welcome any advice/experience.
http://www.sheldonbrown.com/rinard/carbonqa.htm#Painting
I'd also be interested re: a repair. It's a 5mmx25mm gash in the frame which, if it goes another 10 or so mm, means the tube is effectively halved.
Can I repair this?
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nicklouseLives Here
Joined: 20 Mar 2003
Posts: 48249
Location: A Yorkshire man in Sweden
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BigJimmyB
Joined: 31 May 2008
Posts: 374
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Posted Wed Nov 4, 2009 1:54 pm |
With what Nick, repaint or repair?
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aaronmroach
Joined: 27 Sep 2007
Posts: 43
Location: Waddington, Lincolnshire
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Posted Wed Nov 4, 2009 1:57 pm |
I work as a mechanical aero engineer in the RAF and have had limited experience in carbon fibre and other grp's however a quick flick through my multi skilling course notes have given you the followin :
1. Remove decals and their adhesives (use DX-330 or acetone).
2. Hand sand some of the old clear coat or paint, if present. Decals under the clearcoat can be sanded smooth this way. Stop sanding immediately at any spot if you touch carbon. It is incredibly easy to remove carbon by hand sanding. Watch especially near sharp edges (trailing edges on structures) and parting lines on molded parts (often along the center line of monocoque structures). Wet sanding will help keep the dust down. However alays wear a dust mask and eye protection.
3. Clean the surface mechanically and chemically as follows:
- Mechanically clean: remove stuff like paint flakes, old bits of dried substances, stickers and their adhesives, decals, flapping plies, scale, crud, etc.
- Chemically clean: remove grease and oil, fingerprints.
- One last wash: rinse and scrub with acetone until white paper towels come clean.
4. Prime using high-build primer intended to hide small imperfections, which, depending on your level of perfectionism, is optional.
5. Paint using regular paint (Imron, Deltron, PPG, spray can) as usual. Some pinholes may appear this may be due to propellant outgassing. Bake at lower temps do not exceed 100 degrees F or let the paint dry at room temp.
6. Clear coat as normal remembering not to exceed 100 degrees F
Warnings:
1. Do not media blast with any media! Not sand, not plastic, not glass beads, not walnut shells, not steel or ceramic shot. Nothing! Not at even the lightest pressure or for even the shortest time. It is incredibly easy to eat away the carbon and epoxy. Before you know it your part is ruined!
2. Do not use chemical paint strippers! They will attack the epoxy resin that holds your part together. Acetone, alcohol and other solvents are okay, but they don't remove paint.
3. Do not use heat! Some epoxies undergo glass transition as low as 150 degrees F or so. Keep it under 100 to be safe. If it is too hot to touch with your bare skin, it is too hot. That means no power tools (buffing wheels, sanding discs, etc.) and no heat gun paint strippers.
Hope this helps!!!!
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BigJimmyB
Joined: 31 May 2008
Posts: 374
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Posted Wed Nov 4, 2009 2:09 pm |
Thanks Aaron, that's from the site I posted earlier!
No harm in hearing it twice I guess 
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nicklouseLives Here
Joined: 20 Mar 2003
Posts: 48249
Location: A Yorkshire man in Sweden
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aaronmroach
Joined: 27 Sep 2007
Posts: 43
Location: Waddington, Lincolnshire
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Posted Wed Nov 4, 2009 2:21 pm |
Ooops was typing it up from course notes!! Oh well read it twice remember it!!!!!!
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ride_whenever
Joined: 17 Oct 2006
Posts: 8281
Location: United Kingdom
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Posted Wed Nov 4, 2009 2:26 pm |
lol, RAF notes and sheldon brown's source have exactly the same wording!
----------------------------------------------
456!
silly little bike |
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andrewjoseph
Joined: 29 Jul 2003
Posts: 567
Location: near Afan
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Posted Wed Nov 4, 2009 2:37 pm |
I don't quite understand the original post.
if the main triangle has a gash, how can you be re-using the seat tube? Is it not part of the main triangle? Oops, my mistake, just re-read the post properly.
You say you have a new aluminium frame but are talking about repainting the chainstays. Are you talking about putting the new aluminium chain stays on the old carbon front triangle?
My views is similar to those above. If there is a gash in the triangle, it is no good, it can't be trusted. it is unlikely the rear triangle of this old frame will fit any other frame apart from another of the same model.
if you get a new carbon frame, will it come with a rear triangle?
make sure the rear section of the alumimium scott match whatever else you want to use.
--
http://www.mtb-guiding.co.uk
http://www.ba-joseph.co.uk/gallery |
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nicklouseLives Here
Joined: 20 Mar 2003
Posts: 48249
Location: A Yorkshire man in Sweden
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BigJimmyB
Joined: 31 May 2008
Posts: 374
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Posted Wed Nov 4, 2009 7:12 pm |
| andrewjoseph wrote: | | You say you have a new aluminium frame but are talking about repainting the chainstays. Are you talking about putting the new aluminium chain stays on the old carbon front triangle? |
I'm talking about using the seat and chainstays from the carbon frame on the ally one.
The ally frame is from the same model of bike, same size, everything, just in ally not carbon.
| nicklouse wrote: |
carbon forget it.
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Why Nick? There seem to be many firms out there who would take this on (depending on the level of damage). I can't see why a good repair wouldn't be OK.
PM me your email address and I'll send you a cuppla pix.
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warrerj
Joined: 18 Jul 2007
Posts: 236
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Posted Wed Nov 4, 2009 8:49 pm |
Why can a carbon frame not be repaired ??
It depends ont he extent of the damage and where onthe frame it is. I've a garage full of carbon, kevlar and epoxy that I've used to repair all manner of carbon bit. Granted no bike frames yet but other things no problem. It may not look as pretty at the end but .....
If it's good enough for Ferrari F1 (where some of the materials come from) then why not a bike frame ???
My ride :
http://www.pinkbike.com/photo/2236156/
http://www.pinkbike.com/photo/2236165/ |
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nicklouseLives Here
Joined: 20 Mar 2003
Posts: 48249
Location: A Yorkshire man in Sweden
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joshtp/mbukman
Joined: 15 May 2008
Posts: 884
Location: the place you drive 4 hours to, WALES! Swansea
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Posted Thu Nov 5, 2009 12:05 pm |
so you want to use the stays and seat post from the damaged carbon frame on the ally frame, fair enough, save some weight.... but why pain the carbon? i actually think carbon and ally look cool together, (presuming the carboin is "raw") and even more if the aly is "raw" why bother painting it? it prob looks cool as it is! it doesnt need to match! have some contrast! my mate has a felt rxe with carbon stays, it looks fantastic! all carbon and alloy together!
"oh dear, i seem to have hit a tree."
GT Aggressor XCR 09 + shiny bits |
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nicklouseLives Here
Joined: 20 Mar 2003
Posts: 48249
Location: A Yorkshire man in Sweden
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BigJimmyB
Joined: 31 May 2008
Posts: 374
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Posted Thu Nov 5, 2009 12:51 pm |
| nicklouse wrote: |
Also there is no confirmation that damage is in some carbonfiber or some alloy. |
Hi Nick - do you mean from me?
I can confirm the damage is to carbon fibre. I'll get pix up ASAP.
Thanks guys.
Josh - I guess it's just a personal preference. I'll build the bike back up on the ally frame and see hot it looks....
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