Carbon defect - serious or not.

[Janchi]

Hi,

last year I ordered LCFS713 and did my own paintjob. Now I am finishing the build but I am still a bit worried about defect on lower tube. I informed LightCarbon about that and they said its not serious and I can use the frame. Still I don't want to be that guy riding the bike while tube fails .

From the inside the tube is perfectly fine as I checked from the BB hole.

What do you think?

To me it looks like there was some manufacturing defect and they filled it with filler.

Thanks!

[jannmayer]

It's hard to say exactly what went on there. It could be that the carbon is solid there but didn't press fully into the mold for whatever reason. Have you tried tapping it to see if there is a change in sound at that location?


Unfortunately, the tap test won't catch many defects, and it's not possible to be certain without an expensive ultrasound test.

[jonnybearback]

looks to me like the frame has had some post production sanding and one layer of UD carbon has been sanded through.
You can see orbital sander marks in the image too.

[Janchi]

looks to me like the frame has had some post production sanding and one layer of UD carbon has been sanded through.
You can see orbital sander marks in the image too.

That is what I think too. As I wanted raw frame. At first they said its not in stock. After few days they wrote an email that they found one. What I think they did, is sanded some painted frame and that's where this defect came from.

One layer of carbon should not be such a problem, but I would like to know also your thought on that.

I've already painted the frame so I cannot inspect it anymore. I'll finish the bike and start riding lightly hoping it will not fail in one shot.

[FlaMtnBkr]

It's hard to say and more pics would have helped. Looks to me like the carbon didn't get pushed tight up against the mold and the empty space filled in with (tinted?) resin and the carbon is likely 1 or 2 mm down.

Is that the seat tube? Carbon is extremely strong and stronger than it needs to be in most places. I'd bet it's perfectly fine even if a layer of carbon were removed (though the other layers should be right behind it). You documented it with the company if something were to happen and from what I've read I'd expect Carbonda to take care of any problem.