Exhaust paint - how many cans?

[FlightRisk]

So a few months ago (September-ish) I finally got around to painting my rusting exhaust. Took it off, wire-brushed it, sanded it, treated it with Kurust and sprayed it with VHT.

The silencer still looks ok but the downpipes are rusted to shit. I think my mistake was I only used one can on the whole thing.

How many cans should a header + silencer take?
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Honda CB500S

[nitrosurf]

I've just undergone the same process myself, using what was supposedly a good quality paint (one of the big cans, 750ml or a litre, I can't remember). I prepped the exhaust well (at last I thought I did) and was really chuffed with the results initially. I left it dry overnight and let it 'cure' at idling temperature on the bike after that. Two weeks and rust started poking through already... In my case I'm thinking that although my exhaust isn't 'rotten', it may well be that the rust has bitten deeper than I realised. I think probably in this situation more paint on top would just delay the inevitable slightly.
I think preparation should have included a good soaking in chemical rust eater after it was lapped and rubbed down, to really get rid of the orange stuff...

My solution is to put up with the minging exhaust and save up for a Motad!

[sickpup]

As above, in my experience exhaust paint never seems to last long so don't worry about it.