Engineering and technical staff often get confused over the various terms bandied about in South African industry such as ‘galvanized’ or ‘cold galvanizing’ or ‘zinc-rich paints’. So, what’s the ...

We have a 30-year-old galvanized-steel door that's suddenly not holding paint. I used oil primer and numerous topcoats, but nothing helps.—DAVID G., WOODINVILLE, WASHINGTON The problem is ...