[79transam79]

I removed my fenders today, after finding a couple of pin holes of rust. The fenders are in great shape but there is a reinforcement piece about 5 inches wide running from top to bottom near the front of the fender. It seems at some point there must have been moisture in there between the two piece of steel, but there's no way to sandblast, or get into that cavity. How would I go about making sure it doesn't' t continue through out that piece. I was thing using por 15 metal prep then the por 15 rust converter. Is there a better way to go?
Thank you