Help freeze plugs and cam plug leaking

Why on earth would you use shellac? It's not a sealer. It's a wood finish. You should use the right thing for the job. I always use high temp silicone RTV. I just skim a dab off of my finger all the way around each plug. Also I try to find the plugs with the thickest contact area as possible. I never use those thin plugs. They never turn out well.