It depends on the steels it's made from. Damascus isn't a single alloy: it's two or more steels forge-welded in layers, and it rusts or resists rust the way those steels do. Carbon Damascus, such as DSC® Carbon, will rust if it's left wet or stored damp. Stainless Damascus, such as DSC® Inox, resists rust once it's hardened, though no steel is rust-proof. Here's why, and how to keep either one free of rust.
Why carbon Damascus rusts and stainless Damascus resists it
Rust is iron oxide. It forms when bare steel sits in contact with water and air, and it spreads faster with salt or acid on the surface. Stainless steels resist it because they contain enough chromium, at least 10.5%, to form a thin, invisible oxide film that protects the steel underneath.
The two DSC® steels sit on opposite sides of that line:
DSC® Carbon is 1.2842 and 1.2767, two tool steels with 0.2-0.5% and 1.2-1.5% chromium. That's far too little to protect the steel, so carbon Damascus rusts like any carbon blade steel.
DSC® Inox is 1.4034 and 19C27, two stainless steels with 12.5-14.5% and 13.5% chromium. Hardened, it resists rust the way a stainless kitchen knife does.
Stainless Damascus reaches full rust resistance once it's hardened
BALBACHDAMAST® is clear that DSC® Inox reaches its full corrosion resistance only after hardening. Billets arrive soft annealed (22-27 HRC) so they can be machined, and an unhardened billet can still spot if it's left damp in the shop. Store raw stock dry, and expect full stainless performance from the finished, heat-treated piece. The hardening steps are in our DSC® Inox heat treatment guide.
An etched surface needs a little more care
Etching roughens the steel slightly. That's how the pattern stands out: BALBACHDAMAST® puts a 20-minute etch of DSC® Inox at about 20 µm of roughness. A textured surface holds moisture and grime longer than a polished one, so dry etched pieces well, and keep carbon Damascus under a thin film of oil.
How to keep carbon Damascus from rusting
Dry it right away. Wipe it dry after washing or use, and never leave it wet or soaking.
Keep a thin coat of oil on it. Camellia oil, mineral oil or a good blade oil all work. Wipe off the excess, and re-oil after use, after handling and before storage.
Store it dry. A breathable cloth wrap or a dry drawer is best. Don't keep it in a leather sheath for long: leather holds moisture against the steel.
Let a patina form. A gray or blue-gray patina from use is normal on carbon steel and gives the surface some protection. It isn't rust, so don't sand it off.
Wipe it after handling. Salt and oil from skin can start rust spots on bare carbon steel.
How to care for stainless Damascus
Hardened DSC® Inox won't rust from brief contact with water or a wash, but stainless isn't stain-proof. Salt water, acidic food left on the blade and dishwasher detergents can still mark it over time. Hand wash it, dry it, and give it an occasional light coat of oil to keep the etched finish looking its best. Don't put it in the dishwasher.
What to do if rust appears
Catch it early. Light surface rust on carbon Damascus usually comes off with a gentle pass of very fine (0000) steel wool and a little oil; wipe it clean and re-oil. Go lightly, because heavy rubbing polishes back the etch along with the rust. Rust that has pitted the steel needs sanding and a fresh etch, which our etching guide covers.
Carbon or stainless: which should you choose?
Choose DSC® Inox for kitchen knives, for pieces that will see water or weather, and for anything that won't get oiled regularly; it's also approved for direct contact with food. Choose DSC® Carbon if you want its high-contrast etch and the piece will be dried and oiled after use. Both are in the size finder, cut to the inch you order.
For the full cleaning, oiling and storage routine, see Essential Care Tips for Damascus Steel.