Bummer. The RIGHT way to do this repair is to cut it open and do a rebuild but you know that already. You CAN also attempt a repair by injecting epoxy into the delaminated area under some pressure...but there is no guarantee of success. To do this you drill a hole at the LOWER limit of the de-lam and then one or more "vent" holes at the top of the de-lam and inject slow cure epoxy under pressure till it exits from the top holes. In this manner you are SURE to fill any voids. Then seal the holes and allow the epoxy to cook and hopefully adhere. This will ONLY WORK if the core is completely dry so if you have water ingress, forget about it. Good luck!
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