Rustoleum has an oil in it to ****** further oxidation (rust), typically on metals like steel and iron.
Hey! I'm trying to use a fully legal word there! Too much P/C here methinks!
OK - let's try this::: "It has a rust retarder" - is that asterisk'd out too?
anyway: I think Reranch would throw a hissy fit if you used Rustoleum for a primer or anything that goes near, under over or inside their paints.
I foresee danger, failure and lots of sanding, re-stripping and cussing in your future.
Stay with ONE brand for best results.