A Fix for Rusted Radiator Tops

"The old radiators looked pristine, and anyway, they’re made of steel! What harm could my little houseplants do?" –Mary Ellen Polson
rusted radiator tops

Can little houseplants really cause that much trouble?

Turns out the previous owner of my 1940s apartment had restored the built-in metal radiators by stripping surfaces down to bare steel and sealing them with a metal-friendly lacquer. Blithely and over time, I set potted geraniums and basil on the radiator tops, occasionally sloshing water as I tended them. Eventually, rust rings appeared on top, followed by long rusty streaks down the metal sides. No wonder New Yorkers paint their radiators! –Mary Ellen Polson

After ignoring the problem for years, I got the idea to test-sand one of the rad tops in an out-of-the-way spot. Shining steel appeared! With my well-loved orbital sander, I took the smaller radiator top that’s in the bedroom down to bare metal. Repeated sandings with successively finer sandpaper (100, 150, 220) produced a surface with the patina of old nickel.

Now what to seal it with? Tommy, the previous owner, must have used a sealer that wasn’t impervious to rust, so I looked for a more durable coating formulated especially for metal.

An online search turned up Permalac, a direct-to-surface clear coating for all kinds of metal. It dries very quickly and won’t change color or develop rust, two characteristics I was looking for. It also protects surfaces from UV exposure, salt air, or in this apartment, dirty New York air.

After visits to two local hardware stores—neither had ever heard of the stuff—I bought the product online, after discovering there was also a lower-VOC formula. Both regular Permalac and Permalac EF contain toluene, a solvent used in paint thinners. While the EF version still has a chemical smell, it has less than 170 grams of VOCs per liter, under the 250 g/l mandated by California law.

The sealer goes on quickly and evenly. It can be sprayed or brushed on, or in my case, applied with a paper towel. I applied several coats, allowing each one at least 30 minutes to dry before applying the next. So far, there’s no sign of rust and the radiators look beautiful. Needless to say, I have no plans to put any flowerpots on the refreshed surface.

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