so is the idea to repair the tank with resin/cf or just to repair it then take a mould of it?

i ask because i'm not sure if a 'patch' repair would be suitable, i guess that all depends on the type of plastic the tank is made from. i have seen people use fg patch repairs on types of plastic before with no success. if its a repair 'patch' that you were thinking of, i would be going down the plastic welding route

yes it is the original

there are resins that withstand petrol as kevlar/carbon fuel tanks exist,

is the original tank plastic?

Hi