That's an excellent and very practical question! The short answer is: it completely depends on the specific materials and coatings used. Many outdoor benches come with hardware that is designed to resist rust, but not all are created equal. Let's break it down.
Typically, quality outdoor furniture uses stainless steel (often Grade 304 or the more marine-resistant 316), galvanized steel, or coated screws and bolts. Stainless steel contains chromium, which forms an invisible protective layer. Galvanized hardware is coated in a layer of zinc that sacrificially protects the underlying steel. These are your best bets for true rust-proofing.
However, "rust-resistant" is not the same as "rust-proof." Even stainless steel can corrode in harsh, salty coastal environments. Standard carbon steel bolts, often found on cheaper benches, will rust quickly when exposed to rain and humidity.
So, what should you do? First, check your bench. If you see reddish-brown flakes or streaks, rust has started. You can replace failing hardware with stainless steel or hot-dipped galvanized alternatives from any hardware store. Applying a protective wax or specialized coating can also add a layer of defense.
In summary, don't assume the hardware is fully rust-proof. Investing in benches with specified corrosion-resistant hardware or upgrading them yourself is the key to ensuring your outdoor seating stays safe, sturdy, and beautiful for years to come. A little attention to these small metal parts makes a huge difference!