When a screw is exposed to moisture and oxygen, it may undergo oxidation, thus corroding. How exactly does zinc protect screws from corrosion? Well, zinc can still corrode, but it corrodes at a significantly slower rate than other metals and alloys.

How long does it take zinc screws to rust?

By comparison, ordinary zinc-plated screws are rated to last about 100 hours before the first red rust appears. Next week, I'll take a look at solid brass, silicon bronze, and stainless steel screws.

Is zinc screws good for exterior?

We do not recommend electro-galvanized screws (also called clear-zinc coated) for exterior applications. They will corrode quickly in contact with the elements. Mechanically galvanized screws are generally suitable for decks and other outdoor projects made of pressure-treated lumber.