I considered powder coating for the suspension parts on my Ace. It's certainly looks very glossy and is good at covering corrosion pitted surfaces. It's also very convenient for the restorer; you simply remove the parts take them to your powder coat-er, who then de-greases, sand-blasts and paints them, you just turn up 3 days later to be greeted by a box full of shiny parts.
But (yes here it comes) it's not a period correct finish, it's way to 'wet-look' polished than real suspension parts should be. It also corrodes internally, and the rust occupying more volume than the steel it replaces, then lifts the coating allowing the moisture to spread further. It's also extremely difficult to remove, necessitating acetone or methylene chloride, ordinary thinners won't work. Nor can it be removed with a wire brush it's just too strong, it is after all a plastic polymer not a conventional paint.
So in line with my original-as-possible renovation I have had the components media blasted, then I've painted them with ultra traditional red oxide primer, then a layer of chassis paint (Frosts 'Extreme Chassis Black) this is a bit like yacht 'spar varnish' in that it doesn't completely set hard, allowing just a bit of 'give' when it gets stone pecked under the car, rather than chipping off. It can be brushed on or I use a finger tip type small spray gun (200cc) to apply it which works very well. I think that will be as close to factory spec as I can get. Then I typically hang them up in the workshop and later walk into them getting paint in my hair
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I'd be interested to hear what other have done?