That's what I am doing on my next restoration. By the time you pay for paint, and proper paint is not cheap, and the time to lay all those layers of paint, and blasting time. I've found a local plant that do blasting and powder coating, they have high turn over so low cost. So my next restoration all the non critical bits like bumpers, suspension links etc are all going to the plant. I'm just going to myself paint the undercarriage and the complex bits which can't be trusted with the minimum wage workers at the plant.Might just end up throwing the bit I was going to spray with a batch of bike bits in having powder coated. By the time I’ve bought a can primer and top coat for one job it will probs be cheaper too
https://rustbulletuk.com/Even if Hammerite can bond with rust, what good is that if the rust is porous and moisture will come in round the sides or through chips and then it's trapped under the paint, moving around under there, rusting the metal away?
Tip-ex can stick to rust, doesn't mean it's any good. Go on YouTube and you'll see videos of supposed "direct to rust" products having failed after a year. No industrial accredited paint manufacturer claims that you can paint on rust, no commercial standard or manual says you can do it, only DIY paints make this claim. The best an accredited paint will say about painting on rust is that some primers are "surface tolerant", but even then all warranty is voided, e.g. Jotun will only validate their warranty if the metal was blasted even with their surface tolerant primers