I have created a mould for a motorcycle seat, While I was releasing the former from the new mould i broke through the green gel coat where there was an air bubble.

Yes. Make sure it is clean and key it with abrasive. It should be OK.

Brian.

Thanks 

As above. Just make sure all release agent traces are gone when you clean the mould. Also make the repair slightly proud so you are sanding down to the original level.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Regarding the mould repair, someone told me you have to cover the gelcoat with a cling film or packing tape, etc... otherwise it wont fully cure. is that for all gelcoats or only certain types, and do you need to flatten the film or just lay it over?

Polyester and Vinylester resins cure tacky exposed to air so you need to either cover them to seal from the air or use a wax additive where the additive floats to the surface sealing it.

You do not get that problem with epoxies.

If you cover it with film, first you have to be sure it releases from resin, then smooth it as much as possible to reduce the amount of ripples that form and hence less sanding.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Just be careful when smoothing out whatever you cover it with that you don't push the gelcoat lower than the surface of the mould again. I remember my first few repairs I ended up doing them 2 or 3 times because I kept pushing it lower than I needed to.