Professionals and Amateurs Together

Rust Prevention


Any suggestions as to how to prevent rust from starting on bench and stationary tools kept in an unheated cellar shop? — Noah Cote


Roy Noyes replies: To prevent rust on tools, it is necessary to understand how it is caused. Contrary to general opinion, rust is not caused by moisture in the air — there is moisture in the air all the time. Rather it is caused when the moisture in the air condenses on the surface of the tool. This occurs when a cold tool is exposed to warm air. If the tool is below the dew point of the air, condensation occurs.

I worked for many years in an unheated shop in my barn with no rusting problems. I used three methods of rust prevention:

  1. I covered the surfaces of my machine tools with a protective coating, Top Cote, which penetrates the pores in the metal and protects the surface much the way a coat of polyurethane protects the surface of wood and also provides a slick surface for wood to slide on. There are several other products on market, such as BoeShield, which do the same thing. They are easy to apply, last longer, and are much better than wax which can rub off on the surface of the wood and prevent finishes from properly penetrating. They also work well in a heated shop and I recommend them to all.
  2. In addition to using Top Cote, I also kept my hand tools in cabinets or tool rolls where they were not directly exposed to the air in the shop.
  3. Finally, I was careful not to let a lot of warmer, moist outside air into the shop unnecessarily.

I suspect that one of the major causes of rust in your shop may be leaving the cellar door and/or windows open in the summer time. However, you can prevent rust by following the steps above.

Tags: Rust