Quote Originally Posted by Peter Dunkley View Post
Hi does this solution promote rusting or just dye the steel. It's RUST blacking I am talking about.
Thanks anyway.
It works because there's chemicals in the oak that reacts with iron, so basically all ferrous steels and alloys thereof. It rusts black in the absence of air and relatively quickly, but slower than an acid would. Where as iron immersed in just water will rust, but very slowly due to the lack of air, O2 in gaseous form.

It's a well known issue in wooden ship/boat building and, why oak on oak, larch on oak built hulls are held together using copper/non ferrous nails and or wooden dooks