my Newmar

Ivylog wrote:
Phosphoric acid is the active ingredient in all rust inhibitors and can be bought by the gallon in the paint department of Home Depot. Using a shop cleaning spray gun you can spray the undercarriage (staying upwind) yourself. Driving in a heavy rain is a good way to clean the undercarriage and once dry I would spray the bottom with Fluid Film using the same cleaning gun. You can buy FF by the gallon.

I'm no chemist, but there is a difference between a rust inhibitors and a rust converter.