Do I need primer when using touch up paint?

[Yota94]

I have some paint that flaked off on the inside of my door and want to touch it up with some doctor color chip touch up paint that I have. Since rust has formed, I abraded the area down to bare metal that measures about 1/4 inch by 1/2 inch. Do I need some sort of primer or am I good to just paint over the bare metal with this touch up paint?

 

[#18FAN]

I'll tell you that's rusted way more than you think that whole seem is bubbled up its got the cancer

 

[Yota94]

I'll tell you that's rusted way more than you think that whole seem is bubbled up its got the cancer

Yup it was pretty bad but fortunately I was as able to get rid of all the rust. I’m just wondering that since I have a small section of bare metal exposed, do I need to use any sort of self etching primer?

 

[#18FAN]

Post after pictures that seam of the entire panel is rust

 

[Vitamin Yoda]

That rust is just the tip of the iceberg. Applying touch up paint to it is the least of your worries.

 

[SC Maintenance]

Wire wheel on a grinder or drill as best you can, then hit it with something like jenolite rust converter.

Then on bare metal - yes best to use a primer.

 

[97prizm]

I have some paint that flaked off on the inside of my door and want to touch it up with some doctor color chip touch up paint that I have. Since rust has formed, I abraded the area down to bare metal that measures about 1/4 inch by 1/2 inch. Do I need some sort of primer or am I good to just paint over the bare metal with this touch up paint?
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I'd start with naval jelly. It will kill any remaining rust and create a barrier to stop rust from forming in the future. Then paint over that.