Rather than basecoating with the metallic, I heavily drybrushed Pig Iron over the black undercoat/primer.
Then I washed all the metals with a thinned Ratling Grime
To give the metals back their shape I reaplied Pig Iron to all the edges, rivets and bolts.
Here I made a mix of 1:1 Pig Iron and Silver RLM01 Metallic and for the most part aplied it to the edges with a dabbing motion so it was less clean. I also added some feathering along the blade edge for interest.
Using a very thinned down Thondia Brown I washed over the "sharp" edge of the blade and then added this into the recesses all over.
To strengthen the rusty look I added another recess wash of Mournfang Brown
In a more select way I add some thinned Light Rust to the recesses and even under some nuts and bolts.