How to Paint a Radiator: A DIY(ish) Approach

We have old steam radiators in our home that I love but they desperately needed to be refinished. We were quoted $10,000 dollars to have our radiators refinished (yes, you read that right 10k!) There was no way we were going to pay that. So in order to save cost we took this project on ourselves… well mostly. I like to call this our DIY(ish) project. We were able to save over $8,000 dollars with these steps we took and by hiring out part of the project. Here’s how to paint a radiator.

Let me start off by saying that these cast iron radiators are extremely HEAVY!! We had some family and friends help us remove our radiators from inside our home. They were all covered in paint that was chipping everywhere.

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If you’re removing radiators, be aware that some may be filled with water and will need to be drained. If you are just painting them in place I would suggest moving them off the wall a little, that way you have some space to get the back of the radiator.

Late Spring or Summer is the best time to paint radiators. The radiators will most likely be turned off since the heat isn’t needed.

What you’ll need:

• Gloves
• Mask/Respirator
• Wire Brush
• TSP cleaner
• Sanding sponge/fine steel wool
• Vacuum
• Painter’s plastic & masking paper
• High Heat Primer
• Rustoleum High Heat Black Spray Paint
• Can Gun (to make it easier on your hands)
• A helping hand to move the super heavy radiators

Step 1 Remove paint

If your radiators aren’t previously painted consider yourself lucky. You can probably skip this part and do this whole project yourself!

All but one out of the nine radiators we have were painted. Because of the chipping paint we decided to hire someone to come and sand blast the radiators in our yard (making sure there was no rain in the forecast).

Sand blasting works by using compressed air to force out tiny particles of sand and glass (in our case) at a high speed to clean and smooth a hard surface. The paint comes right off! It cost $1450 (around $160 each) to get all nine radiators sand blasted.

Sand blasting is the best option to remove paint from a radiator because it gets into all the tight nooks and crannies.

Once the radiators are sand blasted, its important to prime them as soon as possible. The radiators started to rust pretty quickly just from the morning dew. I was able to remove the parts that started to rust with fine steel wool.

Now, if your radiator has minimal paint thats intact you can use a wire brush to remove any loose paint before cleaning. Make sure to vent the air well by opening all windows and protect yourself by using a respirator.

**BEFORE REMOVING ANY PAINT, BE SURE IT IS NOT LEAD PAINT. IF THE PAINT CONTAINS LEAD PLEASE TAKE THE NECESSARY PRECAUTIONS NEEDED TO SAFELY REMOVE**

Step 2 Clean and sand

Lightly sand the radiator. I used a fine steel wool to smooth but you can also use a sanding sponge and clean with TSP. Make sure the radiators are nice and clean before proceeding to prime by dusting well.

Vacuum all the dust and debris from the radiator and surrounding area.

Step 3 Prep area

Since our radiators were outside we did not need to tape around floors or walls. We just laid a tarp down and placed the radiators on it.

However, I did need to protect the surrounding area when spraying the radiator valve. I covered the area with masking paper, frog tape, and Project Source painter’s plastic that was left over from a previous project. The masking paper worked well around the radiator valve.

ScotchBlue has a pre taped painter’s plastic that works well too.

Before you paint the radiator be sure to cover the walls and floors surrounding the area. If spraying your paint, which I recommend, you’ll want to cover a good amount of the area because of overspray.

Step 4 Prime

After cleaning the radiators, it is time to prime them. You can use painter’s tape to tape off any area that you do not want painted. I taped off the thread, opening where the valve connects to the radiator, and top to ensure everything easily connects right back in place.

To prevent rust, I sprayed the radiators with Rustoleum Metal Primer. The metal primer will work just fine but Rustoleum High Heat Primer is the better option for primer. Unfortunately, it has been sold out.

Rustoleum High Performance Enamal Primer is another great option for a primer. These primers withstand higher heat if you’re using your radiators.

Step 5 Paint

My biggest recommendation is to spray your paint on. Brushing the paint on the radiators often times looks messy and you can see a lot of the brush strokes. Brushing paint on is also more time consuming and hard to get into the nooks and crannies.

Take the time to prep your area well and spray your radiator instead. You can spray them with spray paint or if you are interested in a unique color I would recommend using a paint sprayer.

We used Rustoleum High Heat Black spray paint. Its a flat finish and dries fairly quickly. We did two coats and went back for a light third coat on areas we might have missed.

After the first coat we lightly went over the radiators with a fine steel wool before applying the second coat. This part isn’t necessary but I found that the finish turns out a lot smoother.

Because we were spraying so many radiators and for long periods of time I found this Can Gun to be a life saver, well a finger saver 😅.

As much as these companies claim to have comfortable tips on the spray cans, after a few minutes your finger and hands start to hurt. The Can Gun makes it so much easier and comfortable!

Once the radiators were all painted and dried we moved them back into the house.

Step 6 Replace old parts

We purchased new radiator valve handles because all of the old ones were made of wood and broken.

We also purchased new radiator air valves and Split Flange Plate to cover the floors.

The floor plates come in different sizes and we primed and sprayed them black as well.

The total cost which includes all the new parts we purchased ($230) cans of primer and paint ($150), and hiring someone to sand blast the radiators ($1450) came at $1,830 to refinish all the radiators! Had we not needed the radiators sand blasted, the cost would have came in at under $500 bucks!

I am in love with how they turned out. After we got our floors refinished and our walls painted the black adds great contrast.

No more hiding ugly radiators under a cover. Its takes some work to paint a radiator but I promise you they’ll look so good after! Now I can leave them exposed for a modern and sleek look.