The airbox supports were clearly showing their age. The front was bare metal that had picked up a reasonable amount of surface rust and the powder coating had come off the rear support in places which were also showing surface rust.
The front support was easy to treat, the surface rust came off with a wire brush. After that a treatment with K-rust followed by a coat of silver hammerite and it was ready to go back on.
The rear proved to be a more involved job. Once I started cleaning up the areas of exposed surface rust it became clear that it extended most of the way under the powder coat.
Rather than try and clean it back to bare metal myself I took it to a local shot blasters to get it done properly. According to the shot baster, surface rust under a powder coat is quite common on factory parts as they don’t bother to prepare the surface before powder coating. This means that there are any number of surface imperfections, grease and moisture that gets trapped under the powder coat which then causes the metal to rust. After shot blasting the surface of the support was rough which contrasted with the smooth finish I found under the original powder coat which supports this view.
With the support rust free and suitably prepared I took it to the local powder coaters who happened to be running a batch of black items that day so it was ready the same afternoon.
With both items now rust free and properly finished they were re-mounted in the car and the airbox fitted back on.