Some jointers are powder coated for extra rust-resistance.
Other preventative steps you can take are to clean and dry the tool after every use and reduce the tool’s exposure to moisture by storing it in a dry place.
Correct storage
Make sure all tools are cleaned properly before storage.
Brick jointers can be stored in a drawer or toolbox with the optional purchase of a corrosion-inhibiting drawer liner, which is made from non-slip PVC to prevent knocks and bangs, reducing damage during travel. Some also contain a rust-preventative substance that is non-toxic and vapourises to protect the metal from corrosion.