OK, peeps.... sharing yesterday's experience with some OA and very hard to reach rust (inside tubes, inside dropout welds etc.)
Mixed it rich (250grams to 4 litres water) and soaked for 30 minutes.
Water turned yellow (think morning after urine) and rust turned whiteish before disappearing.
Thorough rinse in cold clean water for a good while then into the sun to dry out for an hour or so.
I did end up with some tide marks on the chrome / nickel and the odd strange blemishes which I suspect relate to the quality of the rework the Frameset had before I got it. Some Peek and elbow grease soon put paid to those, though.
Now to treat the internals with ACF-50 and we are ready to build.
Sorry there are no pics; due to the location of all of the rust the "Before"s didn't turn out very well.
Still, I can confirm it works, and that any blemishes can be worked out with Peek. I probably would mix it leaner next time around, though, as the fumes were a bit heady!
