Rust treatment - gutter rails

I have some surface rust in one of my rails. Not on the join with the roof but in the 'cup'.
Any advice appreciated on treatment...as it is not the most accessible of places.
I have sandpaper, rust convertor, and surface paint touch up.
Of course i need to get rid of as much of the surface rust as possible but do I then use zinc primer or etch primer before the top coat??
Planning to do it with an artist paintbrush due to accessibility...

 

Mask it and get Rustoleum in the correct colour rust convert it first then paint it on , brush it if you want as it’s not easily seen !

 

Hi Youngdub, totally agree a terrible place to get to and I have been doing just that with some success. See my restoration of Lottie thread page 9 photos. Rustoleum gets my vote though you might consider some sort of primer to go under it, Bonda or Epoxy for instance.
Happy rustbusting, Martin

 

I used Vactan to treat the rust and then brush on Rustoleum Combicolor gloss metal paint which also has rust killing properties, with a nice soft brush you will get a nice finish and bear in mind Rustoleum takes a little while to dry and harden and it smooths out when drying. I brush painted the whole underbody and engine bay in my van with Rustoleum and it still looks like new.

Any rust converter would be just as good as Vactan.

 

Thanks for your responses.
Rustoleum does seem like a generic product, looking at their website - is there is specific product you would suggest as a primer, and then top coat?
Sorry but there seems to be so much choice

 

We usually get Rustoleum from Avenue Coatings in Slough, they sell on ebay as tools-paint, you can either choose a RAL colour or ask for a VW colour if you give them the code, very helpful and reliable supplier.

For such a small job, no point over thinking it. Sand the gutter rails lightly, brush on rust converter on the rust patches, let it dry well, brush on the Rustoleum, job done. After a few weeks you could brush on a second coat.

Clean rust converter brush in water. Clean Rustoleum brush in white spirit. Simple.