Recommend Black Paint for Cast Iron


23 Jul 2010
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United Kingdom
I have a cast iron pedestrian/garden gate that needs painting.

It is real cast iron (not steel or wrought iron).

Normally for cast iron I leave it to form a patina of surface rust.
Or apply layers of "Black Stove Polish & Grate Polish"
But with gate I want it to be black, and protected from rust.

Any suggestions on best paint for Cast Iron?

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Last summer, Lidl sold a a semi matt black paint suggested to be for outdoor metal and it hinted at being similar to Hammerite and cheap, around £6 a pint. I used it on my drive gates and the garden gate, which are galved steel/ wrought iron. Due to the galv, there was no rust, they were just chipped and untidy. Quite thick, but spread well, it went on well and dried quickly, just like Hammerite used to. It seemed to be some sort of tough resin based paint. It hasn't chipped, despite lots of use of the gates, though it has dulled a little in the UV.
I don't like Hammerite, so if it was me I would use a metal or universal primer (these are expensive, so you can use red oxide if cost is a problem) followed by an oil-based undercoat and black gloss, which IMO gives best protection.

Gates are fiddly to paint, you might like to thin the paint a bit for ease of application, but apply two topcoats, as thinned gloss may pinhole.

Or, ask around for someone who will spray them.

BTW if you have lift-off hinges, put two or more stainess washers (C-form) over the pins, lightly greased. They will prevent the gate and hinge rubbing against each other, scraping off the paint and going rusty. Being flat and greased, they will not grate or squeak and the gate will swing more freely.
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Yes hammerite is one of those interesting paints that have mixed responses.
As this is a 150 year olds cast iron, with details that I do not want to loose to thick paint I was not wanting to use hammerite in its thick state.
Cast Iron is an interesting metal, very strong and difficult to cut, but very brittle (both because of its crystal structure).

Nice idea regarding the washers.

Cost of paint is not an issue (to a point).
For steel I would always use a primer, but with cast iron I was unsure if a primer was needed (as said i I normally blacken or leave it for internal/dry locations).

So thanks for the guidance.
I recently restored a cast iron bench with lion heads and all trimmings.
After stripping the 20 layers of paint, i used a 4:1 hammerite black gloss and thinner.
All details still perfect and bench beautiful.
Only "defect" is that you must let dry each coat 2 days to get it perfect.
Johnny, thanks for that and the suggestion of a thinner.
2 days to dry between coats - will have to do that in garage then.
Thanks SFK
Johnny, thanks for that and the suggestion of a thinner.
2 days to dry between coats - will have to do that in garage then.
Thanks SFK

As said, the Lidl paint despite being thick, spread very easily, much better and easier than I remember the Hammerite ever doing. I worked in the sun, on a warm day, removing the gates to wash them down and allowing them to dry thoroughly before painting. I removed the first one, had it washed and painted, before removing the other two. By the time (two hours later) I was ready to paint the last two, the first was dry and ready to go back on.
One thing that some people use with spray paint cans is to store them in a bucket of hot water.
That might help with brush paint time above?

POR 15 is used on car chassis and bike frames but needs a top coat for UV

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