painting cast iron pipes

[steg]

I have cast iron drain/down pipes at back of house that need painting they are quite rusty looking, will I have to clean all the rust off before painting or is there a paint that can go over the rust?

[Vicasso]

I use this stuff

http://www.hammerite.com/uk/tips/index.html

[e.crespo]

What about this? http://www.idealworld.../categories@lt;{8011}
There is a video as well.

[123everton]

Take the rust off with a wire brush and go over it with "Kurust" or "Jenolite" then paint it with "Hammerite"

[steg]

excellent, thank you all very much.