Rust treatments- old and new

[majcd213]

Hi All- back in the early 70s when I first started motoring I had an old A40 Farina. It was a little rusty even then and I formulated an effective approach to its treatment. This was wire brush or rub down, apply Kurust, wash it off with methylated spirits, prime and paint. The point was that then Kurust was sold with the byline that it didn't react with bare metal or paintwork: You just brushed it on- left it to react and then washed it off- using the recommended "Kurust wash" if you could find it- meths if you couldn't and the metal was still shiny underneath. The rust patches alone turned a pleasing blue/black. This meant you could prime and paint straight on top- maybe with a little skim filler or filler-primer if the rust etching was bad.
Nowadays it seems that Kurust, and all related products I have tried, DO react with bare metal- brush them on and they dry/set or cure (whatever is the correct term) to a thickish blue/black covering all over the work piece. This is never flat enough to spray onto and rubbing it down seems impossible as it just rubs off in tiny balls- even after a weeks drying time! The stuff is fine if I'm undersealing- but I can't get a good base for spraying.
Does anyone have any tips on this- or know of a compound in the old-fashioned vein?
Thanks
Mike

[jpsh120]

I have recently resprayed the engine bay of my 71 rapier and used jenolite with great success to treat rusty patches. Having read several articles on the subject of rust treatment/converters I went for jenolite and it proved to be excellent.
I did wipe off any residue before primer with zinc primer as opposed to painting on top but the results are very good. Only time will tell I guess if rust has been banished.