Refinishing cast iron radiators, big budget edition.

Last summer, I did a small budget cast iron radiator refinishing job for our kitchen. Very small—about $28. It went really well—I’ll most likely be doing the same thing for most of the other radiators in the house that are awaiting refinishing. Back in 2008, though, we went with a super-spendy alternative for two of them. We were in the middle of renovating the upstairs bathroom at the time and we’d decided to send out the sink and tub to be refinished off-site, so it made sense to throw in a couple of radiators. I’ve been getting a lot of questions lately about what we had done, so I thought I’d do a proper post and show off the results.

Before (2006) and after (2014)! It’s hard to tell from the before shot, but the radiator had a lot of rust buildup on it. Someone had recently given it a silver re-coat (note the overspray on the wall above), but there were layers and layers of peeling paint underneath. All those layers of paint make radiators less efficient, and as the bottom layers fail further, the top layer deteriorates pretty quickly. It’s a losing battle. At a certain point, you have to take the existing paint off and start over.

We bought the house during heating season, and this radiator’s valve was leaking a ton of water into the kitchen ceiling below it. We have a single-pipe steam system (as opposed to dual-pipe hot water), and I don’t think the steam was even making it through the body of the radiator—it was just condensing at the valve and leaking. Between that and the broken boiler, I understand why the tenants were using an electric space heater back there! We had a plumber in right away to disconnect the radiator and cap the line above the floor so the leaking would at least stop while we figured out what to do with that room.

We used a local place to do our refinishing, Extreme Powder Coating in New Windsor, New York. They showed up with two burly guys who carried everything down the stairs, out the front door, and into the back of a Hummer. Let me tell you, moving two cast iron radiators, a cast iron sink, AND a cast iron clawfoot tub is no joke. This radiator alone probably weighs about 400 lbs, and clawfoot tubs are around 300…so…yeah. It was hard to watch them go down the stairs. I kept envisioning the guy on the bottom—who was walking backwards—losing his grip and being squashed under the tub.

A few weeks later (it took them longer than expected because sandblasting the tub took some trial and error), everything was redelivered. The detail on the radiator looks so crisp without all of the lumpy paint under it. Sandblasting removes everything down to the bare metal, so even just not having 100 years of filth between the fins is a relief. Powder-coating, by the way, is a relatively safe process in terms of toxicity—unlike spray paint. There are no solvents used (it’s a dry powder that gets baked on), and no VOC emissions. It’s also super durable, so a well-maintained radiator that’s been totally stripped and coated should last a very long time without needing to be re-coated.

This winter, we replaced all of the vents on our radiators. Depending on the type, vents typically cost less than $20. They’re easy to change out, and it’s a simple fix that will get rid of steam whistling and sputtering. That’s the kind of thing I’m talking about when I mention radiator maintenance—if you have a leaky vent that’s dripping condensed steam, you’re going to wind up with rust. Just buy a new vent! Here’s a good instructional video from This Old House.

This is embarrassing to admit, but the refinished radiator sat, disconnected, in the studio for FIVE YEARS before we had the plumber come to install a new valve for us last fall. We had to change some piping in the basement beforehand, and we couldn’t do that until we dealt with the kitchen radiator…and, of course, the kitchen renovation would up dragging on for an eternity, so…that’s just how it goes. That room has been preeeeeeetty cold in the winters, let me tell you!

I still need to take care of the exposed part of the supply pipe. I’m going to paint it white with a enamel made for metal, and get a fancy brass flange to hide the chewed-up wood around the hole in the floor. I’m thinking about this pretty floral one, probably in white. I need one for the kitchen radiator, too, but I’ll go with bare brass in there.

Steam radiators need to slope toward the boiler/supply pipe so that steam doesn’t get trapped in the system and condense. When you hear banging in radiator pipes, that’s trapped water that can’t be displaced by rushing steam. Large steel washers work well as shims! See the rust under the feet? Yup, that’s the result of a leaking vent. Fortunately we caught it in time, and the rust hasn’t spread or damaged the coating.

Most of our radiators were made by the US Radiator Co. in Dunkirk, NY. I had a tough time finding out much history about this company, but I did spend some time looking at their “complete” catalog (PDF). I’m not sure what year it’s from, but it definitely postdates the ornate radiators in our house. My guess is that most of our radiators are from around the turn of the century. I love that something so simple can still provide reliable, efficient heat 120 years after it was built, and that it looks so pretty while doing its job.

Costs for having cast iron radiators sandblasted and powder-coated can vary wildly depending on your location and the size of your radiator, but you can expect to pay $200-300. That doesn’t include the cost of having a plumber come in disconnect the radiator (and, just as importantly, cap the line) and reconnect it/install a new valve later, which can run you up a couple hundred dollars more if you can’t do that part yourself. So no, it’s not $28 worth of spray paint, but if you have a radiator that’s in really bad shape or you’re refinishing a bunch of other stuff at the same time (or if you just have bags of money lying around), the results are excellent.