Metal bulkhead stairs rusty

[Donb33]

My metal bulkhead stairs are temporarily exposed while we excavate for an addition. As you can see in the picture there is a fair amount of rust on them. What can I apply over the rust to prevent further deterioration?

 

[AC Power]

There isn't anything that can be applied "over" rust on any metal material. Some of these homeowner aerosol spray cans (from Home Depot or Lowes) that claim rust inhibitor are just gimmicks.

The best you can do is grind the rust out, and use an automotive body filler and glazing putty (with a hardener/catalyst) to fill-in & level the affected area's. Sand to an acceptable finish. (NOTE: Do NOT use any automotive body filler that does NOT require a hardener/catalyst....they are not good enough quality)