Sealing in rust

[anonafsir]

Hi, I wonder what happens if you seal rusty corten steel with, for example, foam insulation (PU). Say you insulate a rusty metal construction on both sides.

Will it stop rusting further, or will the metal rust through completely and possibly cause a weakened construction?

 

[ArneTW]

Rust needs water; if it becomes sealed, corrosion stops. If not, it continues to rust.

 

[C.Lundin]

If it doesn't get both oxygen and moisture, there's no danger.
Look at reinforcement in concrete, for example. In 99 cases out of 100, the reinforcement is rusty when assembled, which is never a problem precisely because it is enclosed in the concrete. The concrete remains moist, but as long as oxygen is not introduced, the problem does not exist.

 

[anonafsir]

Thank you!!

 

[marka]

Corten has the special property of creating its own rust protection, oddly enough, the rust protection consists of rust that becomes so dense that deep rust is avoided.