Hi everyone,
I had a small crack on my handmade italian carbon road bike frame and took it to a very well-known and respected carbon framebuilder for repair (he's not who made the frame). He took one look and told me he couldn't work on it because the frame is defective and it's dangerous.
He pointed out what looks like plastic (possibly packaging material from the carbon layup process) embedded inside the tubes in the damaged area and possibly in the entire frame. According to him, this shouldn't be there and makes the frame compromised and weak.
is it really a manufacturing defect? the person who made the frame is also very know for making good frame made in italy… did he messed up an entire frame in that way?
Any insight would be really appreciated. Thanks in advance!
by n0tSnail
10 Comments
Whoa. I am no carbon repairer guy, but I have never seen anything like that. And I own a carbon bike that got repaired.
/r/framebuilding
I would call your frame builder
Photographs are not great, but I imagine you are talking about the yellow layer between the carbon and the paint.
This is all unrelated to the damage that was intended ot be repaired? This is the general section of the problem area after the paint has been stripped, or?
I would ask the manufacturer of the frame about what that yellow stuff is, if that is the concern of the repair guy. Or indeed ask r/framebuilding or maybe some other sub-Reddit that specializes in carbon fiber building.
Its hard to tell from the pictures but it looks like a whole outer layer of carbon came off the main structure of the down tube and the yellow plastic was underneath?
It would be hilariously bad QC to laminate carbon prepeg without remove the plastic handling layer. And yes, that means there would be no structural bond between that outer layer and the inner monoque structure.
I use to make carbon tubes for a different application. We would roll prepreg onto a mandrel and the we had the machine that would essentially wind a layer of tape around it to compress it onto the mandrel while it baked. Then we take the tape off and pull the mandrel. We would get a finish just like you see on the frame, here. That plastic almost looks like the tape we would wind onto the carbon. Just speculating but I wonder if it got forgotten and left of and painter over? That’s crazy though.
I’m not a repair guy, but I work with composites for a living (in the defense sector) that yellow thing is most definitely not supposed to be there.
It does look like someone forgot to remove the protective film from one of the layers.
That frame is 100% defective.
https://reddit.com/link/opzj13n/video/pph3gt0sfj5h1/player
heres the video
Ok again as many have said, I’m no carbon guy but I like to play around in my shop.
Around 8 years ago I ordered some pre-made carbon tubes from Enve composites, and stupidly ordered un sanded tubes – which I still have.
These have the same look as the inner tube under the yellow film.
Again I’m not a composites guy, but to me it looks like they wrapped the base tubes w/ pre prig and I can’t specifically say when that yellow layer is but I don’t think it’s supposed to be there.
Best of luck, that’s all I got !
That is ridiculous. Now we need to know the brand. Is it 3T or something more boutique?
Looks like someone left the film on the sticky side of the pre-preg