On 10/04/15 14:34, Dave Plowman (News) wrote:
In article ,
Mark Allread wrote:
Can anyone recommend (through personal use and not hearsay/web hype) a
good rust killer plus primer to use on a small awkwardly located rust
spot on a car please. Awkward in that its on the crease of a panel and
under the rear light cluster which I'll need to take out to properly
cure it.

Sand (or grind) it down to bare clean steel then repaint. No such thing as
a rust killer that works for this sort of thing. It would need to get
under the surrounding paint, and none do.


The correct thing is to remove all loose rust first, then use phosphoric
acid that turns any small bits of rust to iron phosphate which is stable
and takes paint well, then fill and paint.

The acid doesn't stop the rust, but it turns loose pitted rust that can
get water under paint, into good stable phosphate that is more resistant
to water creep


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