I bought a carbon roof, overall condition is okay, just some minor set back that is not noticeable in a few feet.  Up close you can see 1 large crack on the side, and small ones all the around the roof.  My problem is the long crack, it seems like it has gone through all the way down to the carbon itself.  Is there a way to fill the crack?  Do you just sand it and hope the clear coat can get through or do I need resin?  How do you spray the clear?  Do you sand first, then buff, then respray the clear?  Here are some pics

LONG CRACK







Here's a sample of the crack that goes around the roof.  Seems like these are sandable then buffable





Here's a big crack but I believe weather trim will cover this part but might as well fix it.

To be honest, for a new product i would be returning it.

simple cracks can be cosmetically filled with resin either by sanding back or flexing ans syringing fresh resin in, then sanding to match and polishing back up.

However you have lots and lots of cracks which is going to be many hours work.

Also any that have gone right through to the reverse as well, will have compromised the strength significantly meaning you would need to add additional reinforcement to replace the lost strength where the carbon has itself broken.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

It's a used product.  I think I will go on ahead and sand it and large the cracks a little bit and fill it with resin and see if that will help!

Your proposed repair will be weaker than the original part. This means:
If the cracks are the result of an unusual one time event (e.g. crash) then the repair might work, but it's still likely that the damage will reappear since such cracks and damaged fibers are stress risers.
If the cracks appeared during ordinary use then the damage will certainly reappear. Since the proposed repair will not result in the original strength.

If the part is cosmetic, no big deal. If it's structural... well. Don't count on it.

Looks like a sun roof infil?

This is a CF roof available for BMW E46 M3.  This is an aftermarket made my VORSTEINER.  I'm planning on removing my current roof with sun roof and replacing it with this.  Crack started because I think the previous owner installed it wrong and it wasn't caused by an accident or weakness of the roof, more like because of the installation.

Very resin rich part ! Photo 1+5also show why you should roll carbon !

Seems to be 1 cosmetic ply of carbon ? looks like its caused by fitting and bolting down the flange and cracking the resin

Grind out crack,fill and rub down and lacquer

extra ply/plies on the underside or when you fit adjust fit so flange area is correct

Myself I would liquid shim it onto glue then bolt up once glue is set