POR-15 products work well for this, too. That's what I used. They have a steel reinforcing fabric that you can lay down and then coat with POR-15. When it hardens, you can drill through it. Makes a nice seal before painting. It's been a few years since I did this, but I think I described it right. I've used most of their products with good success, Marine Clean, Metal Ready, putty and their enamels. You might want to check them out.
