Thanks gadge :), just wondering, do you prefer getting straight Phosphoric acid and diluting if needed or do you recommend just getting a specific ready-to-use rust remover/converter?
If you can get your hands on Concentrated [85%] Orthophosphoric Acid, dilute it at 1+9 ratio. That works for me. As always, add the acid to the water, not vice versa!
The rust removers are easier to get for most folk, hence my recommendation. The commercial rust removers also usually incorporate some sort of surfactant, to act as a degreaser for metal that isn't squeaky clean.
Also, picked up a set of those twist knot angle grinder attachments, seemed to work quite well.. even on my finger :p .. took off a heap of rust from the blade plate.. primed it up, gonna give it a quick coat of black and chuck it back on the mower..
Yup, they're pretty aggressive at removing rust. Only thing is, they won't clean all of the residual rust out of pits in the surface, unless the pits are shallow. My procedure there is, to give the pitted areas the Phosphoric Acid treatment before painting. If appearance matters [as in the upper side of a mower deck], metal-filled epoxy such as Devcon or JB Weld can be used to fill the pits, after they've had the acid treatment.
