Short answer: Yes, mostly-but it's not 100% rust-proof. Let me explain, 'cause I've had a few stainless steel knives, and some held up better than others.
First, stainless steel has chromium in it, which creates a thin protective layer that stops rust from forming. That's why it's way better than regular carbon steel-my old carbon steel knife rusted after one use in a damp bathroom. But here's the catch: if that protective layer gets damaged, rust can still form. I scratched the blade of my first stainless steel knife with a wire brush (when I was cleaning dried spackle), and a few weeks later, there was a tiny rust spot where the scratch was. Oops-lesson learned: don't scratch the blade!
Another thing: If you leave water on the blade, even stainless steel can get surface rust. I left my knife on the sink edge after cleaning it once-had a little water droplet on the blade, and the next day there was a faint rust stain. It came off with a damp rag, but it was a reminder to dry it thoroughly. So "rust resistant" doesn't mean "rust proof"-you still gotta take care of it.
Quality matters too. Cheap stainless steel knives (the ones from dollar stores) have less chromium, so they're more likely to rust. My Warner and Stanley stainless steel knives are 5 years old, and not a single rust spot-they're made with 430 stainless steel, which is designed for tools. The cheap one I bought? Rusted after 6 months. So if rust resistance is important, spend a few extra dollars on a quality brand.
One last tip: If you do see a tiny rust spot, don't panic. Dip a rag in white vinegar and rub it on the spot-vinegar dissolves rust. I did this with that scratch spot, and it disappeared in 30 seconds. Then dry the blade right away, and it'll be good as new.
putty knife from hanke tools
