How to Paint a Cast Iron Urn
My friends bought a new house last year and asked me for some help with their garden in the spring. The previous owners had left behind a cast iron planter, but it was in rough shape:
Someone had drawn on it with crayon and it was quite rusty. I get that rust on old things can be beautiful…
…but that wasn’t the look they were going for. Also, this was not a heirloom piece of cast iron–a coat of black paint was needed to make it look its best.
We put plants in the urn, as it was, last year, but I vowed we would do better this year. So in May I hauled it home and set out to spruce it up.
Before painting it, I needed to get rid of the visible rust. I scraped off loose bits with a putty knife.*
And then used a wire brush* to get at the rest.
All of the instructions for painting cast iron that I found online said that I needed to get rid of all of the rust, right down to bare metal. The scraper and the brush did a good job with loose rust, but there was still a bit. More searching online for rust removal told me that I should douse the urn with acetic acid (i.e. vinegar), and that this did just as good of a job as any commercial rust remover. I tried it, but I can’t say that I saw a real difference.
Eventually I decided I’d removed as much rust as was going to come off, and proceeded to the painting stage. For this, I bought rust paint* in a black matte finish:
In hindsight, the version in a spray can would have been easier to work with, but I opted for the can and applied it with a paintbrush.
I hauled it back to my friend’s house, and we filled it with plants:
I think it’s a huge improvement. And even more so by the end of the summer, when it looked like this:
Besides the paint job, another way we improved the looks of this urn was to place it on a cement paving stone. These types of planters really aren’t meant to be sitting right on the soil, or on a lawn–they should be on something solid.
*Disclosure: some of the links on this page are affiliate links, meaning, at no additional cost to you, I will earn a commission if you click through and make a purchase.
In the future for anyone who wants to do it right and no really knowing what to do with all that rusted metal even cast iron. Por 15.its easily found and for under 100 bucks your doing a job that’s every bit as good at all the top guns out there that think sand blasting your metal pieces is what’s needed. It’s called por 15 as in paint over rust. And that’s exactly what I did. Obviously I cleaned my metal urns the best I could but in the end. It looked better and in my garage more better than when I purchased them new. In the end with all said and done. I did hit it with tremclad mat black finish and looking at it you just see how great any plant will look with mat black or any black for that matter. For all you home owners that want to do it right to make it last. You will remember reading this. To all. Good luck Don koch.
Don,
We are in a very similar situation with an old cast iron urn. It is a lot more detailed and we had more green paint on it than in the pictures above. We pressured washed [including cleaning solution] to remove the mud, some of the green paint and rust and then began using paint remover from top down. The top decorative ring cleaned very well down to the metal however the rest of urn was something else. What resulted, while using the paint remover the entire surface became a black thick tar like coating material that is virtually impossible to scrape and clean off. I can send a photo if you can provide a email address. It looks like we will either leave to as it is [not preferred] or paint over the tar like material with some type of paint/coating that would adhere or dry. We just can’t solve the mystery of where this black gooey tar came from. From the original green paint? Just baffling and thought you might have some ideas.
John
The way that you painted it with an alkyd rust inhibitive paint will give you a few years of service before you see the re-emergence of the rust. My recommendation is in the future to use a surface tolerant epoxy primer and hydrophobic acrylic finish coat. The limitation of the paint that you used is that it is water soluble and has poor U.V. resistance.
When I did my cast iron urns I had them abrasively blasted and primed with a moisture cured zinc. I applied an epoxy intermediate coat and a fluoropolymer urethane in a satin finish. I will never have to paint these again in the next 20 years.
In the winter to prevent water in the urn from freezing and pressing expansion into it — thus rupturing or damaging it. —— what should one do — i — flip it up side down but then the base inverteted holds water and will crack — or etc… what can one do to store it safely from winter water freezing in ot and resulting in expansion problems —— do you store it where it is [ outside or etc ] —? what can one do that has no shed or over hang or ets — ? ? —
Cover it up with black trash bag and secure at base.
I have not found cast iron urns to be damaged by winter freezing and thawing (unlike terra cotta or clay pots, which would likely be damaged). I create winter arrangements in my cast iron urn, just sticking the evergreen branches and such into the soil, and it has been fine.