Painting Cast Iron Downpipe

[edward55]

Hi All,

Can anyone tell me what paint I should use to treat a cast iron downpipe? I picked up some salvage pipe to replace a piece that's shot, and painted it with black bitumen-based paint (with Hammerite undercoat). When I went to put it up a few weeks later it was still wet/sticky to the touch.

I guess I've made a boob using the bitumen stuff - can anyone advise me what I should have used, and whether I can just paint that over the incorrect stuff, or will I need to strip that off somehow? Can't imagine how I'd strip it, given how sticky it is.

Thanks a lot for any advice.

 

[stuart]

I used linseed oil paint for mine and it's worked very well. It allows the iron to dry out a bit I expect so will delay rotting hopefully. I've only painted the outside of the gutter for the same reason.

not sure about your bitumen though, but I'm sure someone here will. try scraping or burning it off? I would rather leave it than trying a few litres of solvent though - very wasteful and messy

 

[Penners]

I went to put it up a few weeks later it was still wet/sticky to the touch.

I guess I've made a boob using the bitumen stuff

Actually, I wonder if your boob was using a Hammerite undercoat.

I have no specialist knowledge in this, but I have heard that Hammerite isn't like ordinary paints - it relies on some sort of catalytic reaction to harden and to protect the surface that it coats.

I wonder whether the two coatings are simply incompatible.

But I repeat - that's not an expert view in any way.

 

[Craig]

We are using a Sikkens Rubbol gloss, as though its a "modern" paint it has an 8 year painting cycle. Will tell you whether it was a good idea in 2014 ish...

 

[edward55]

Thanks for the tips folks. Linseed Oil and Sikkens - I never even considered using those, I thought they'd be suitable for wood only.

A couple of weeks later and they are no longer sticky/tacky. Strange because they'd been painted for at least a couple of months when they were sticky. Perhaps they get like that in warmer weather.