i have a 19 foot carbon fibre surfski & a few cracks are opening up where the last owner repaired it.

can anyone tell me the best product to use for fixing cracks and doing patch ups?

ta.

To avoid repairs cracking, you have to restore full integral strength.
So the damaged area has to be sanded out, tapering through the laminate thickness over about 30mm, then re-laminate with carbon and epoxy using the same numbers of carbon layers. If sanding all the damage out is too difficult you may get away with patching over the top. But this will be a stiffer area than the rest and may lead to an increased stress on the area next to the repair.

stamp said..
thanks decrepit.

crusty- i'm ok with glass, but i thought carbon fibre was completely different to work with?

The main difference is that it doesn't go transparent when you wet it out, so you can't tell when it's saturated. You just have to keep going over it until it doesn't soak up any more resin. If you're in the habit of trimming hte cloth when the resin gels. you have to do that much earlier with carbon, as it's so much stiffer. Also wet out fibres can be deadly, needle sharp and very stiff, the only good point is that unlike fibreglass splinters you can see carbon.
You also don't achieve the full strength of carbon with polyester resin, it's too brittle, and will crack before the carbon gives way. If you want max strength you need to use epoxy.