Cleaning outside of Cast Iron bath for Painting

I've been advised to clean off the rust and old paint and repaint with hammerite type paint. Just how much rust will hammerite tolerate? I'm using a abrasive disc on a 115mm grinder, and its taking off the paint and surface rust fine but the surface is somewhat uneven and there's rust in the pits. Do I need to treat for these rust areas? The bath is outside upsidedown so access is as good as it can be.
Rob
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Rob Graham wrote:

I thought the whole point of finishes like hammerite was that you could just brush of the loose rust and then paint directly over what was left... at least that's what the advert on the telly used to say ;-)
--
Cheers,

John.

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snipped-for-privacy@lineone.net (Rob Graham) wrote:

Hi, I've used hammerite in the past on an old petrol tank from a car, and once I had removed the loose rust with a stiff wire brush, the hammerite did it's job perfectly. The paint will take care of any rust providing that it is not actually causing the metal to flake, so once you have ground away the paint and removed any flaking metal, it will be fine. Also, make sure any solvents or paint strippers you use have been thoroughly cleaned off before painting.
--

Martin

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Rob Graham wrote:

just wirebrush, treat with 'jenolite' or other phosphoric or chromic acid stabiliser. wash off teh acid, and use a decent paint.
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Rob Graham wrote:

well, either its stuck or it will fall off - just stabilise it as discussed, and coat with something gooey. you might want to brush a thin epoxy coat over everything.

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