Whew, that's a bad one! What Atoll said, use epoxy
for this layup
. Back grind it further too, especially at the aft end. There are a number of threads here on coating a lead ballast keel. Basically make sure it's clean and dry, and coat it within half an hour of sanding
the lead bright. Then while it has wet epoxy on it take a piece of 60 grit wet/dry emery paper and wet sand the resin into the lead. Then glass her up. Don't try to do more than a few plies at a time or the whole wet layup
will fall on your head! Been there, you don't want to be that guy...