CF Repair?

[Bizzarrini]

Hi Guys!

a friend of mine just bought an M900, and it has a carbon fiber front fender. The fender has a crack of about 2 inches, but it's still quite rigid. Is there any way to repair this, so it at least looks fine again?

Cheers!

[zarn02]

i'm not really the guy to ask ("so why are you answering, asshat?"), but i would think you might be able to sand it down, and reapply resin to the affected area. isn't going to fix the problem, but it might make it less noticeable.

i'm googling "carbon fiber repair" at the moment, but haven't turned up anything concrete.

(so just wait around until someone smarter comes along. )

[Bizzarrini]

lol, thanks for the effort though! 

I read that CF is quite bad to 'inhale', so I assume wearing a mask would be a good idea when sanding!

[ducpainter]

Breating c/f dust is bad...probably you won't die if this is the only repair you do, but wear a mask.

I would reinforce the crack on the back side. You can use fiberglass for that.

You will never make the crack disappear, but a little clear epoxy will make it better.

The important thing to remember is to be very neat with your adhesives.

None of this stuff sands very easily.

You will probably need to clear the part afterwards to fill scratches from sanding the epoxy used to fill the crack.

[Duc Fever]

Just put a cool sticker on it

[MendoDave]

If you can find a store that sells carbon fiber get some. You should do a vaccum bond but it will be OK with out one. Use Sand bags instead (about 5 pounds should do)

Sand down the underside of the fender where you want to apply the Carbon patch. While your at it, Take a look at how the cloth weave in the fender is aligned.

You should try and align the weave of the new Carbon at least 45 deg. from the current weave pattern. So mix up a little resin and wipe it on over the cloth, being sure to thourghly wet the cloth with resin, but also use your plastic spatula to remove all the excess resin from the cloth that you can. Too much resin will weaken the repair. It wont hurt to use two layers of Carbon cloth, each oriented differently.

There is a nice trick that works pretty well for getting the right amount of resin. Put the carbon and resin between Two pieces of clear plastic film. the sqeegee the resin out of the cloth through the plastic. Then remove the carbon (or even cut the carbon to shape with some scissors while its still in the plastic) from the plastic and that should be just about right for the cloth to resin ratio.

Also make sure that the repair extends at least 2.5 CM beyond the crack if possible.

Then use some release cloth to put on top of the repair so that the bean bags or sandbags wont stick after its dry. This step makes a better bond and will prevent water from getting in. Try and put this whole setup under a heat lamp if you can.

I don't have any advice about making it look pretty on the top side of the fender, but you might ask ducpainter about it. In my experience if you put resin in the crack it will look like you put resin in the crack and then you will have to sand it smooth, which means the sanded area will look sanded, and you will have to clearcoat, but then there will be pinholes and so on.

[dlearl476]

In my experience if you put resin in the crack it will look like you put resin in the crack and then you will have to sand it smooth, which means the sanded area will look sanded, and you will have to clearcoat, but then there will be pinholes and so on.

+1

Lots easier to fix the crack than to make it cosmetically 100%.  If cosmetics is what your buddy is about, probably time=money ahead just to buy a new one.  I got mine on ebay for $90.  I have a bunch of CF stuff and I don't think you could even buy the materials for $90.  If you want to try, I'd recommend fiberglast.com