How To Paint A Radiator

  • Learn how to paint a radiator in 9 simple steps
  • Includes guidance on using spray paint or a roller
hand with brush painting a radiator white

Flaking, peeling, chipping – few appliances can become quite such an eyesore in the home as an old radiator. And few objects appear as paint-unfriendly as a burbling, sputtering, steaming radiator. But it’s doable. True, painting a radiator is not as straightforward as painting a bench or a fence – far from it. However, if you take a disciplined and methodical approach, you can not only paint your radiator, you can actually make a pretty sharp job of it.

The only deal-breaker is whether or not your radiator has lead paint. You can check if your radiator has lead paint using an inexpensive testing kit. If it does, you should not attempt to paint the radiator because the first step in doing so is to scrape off the old coat of paint which you should not attempt to do because lead particles and dust are extremely toxic. Removal of lead paint is a job for knowledgeable professionals.

If you must re-paint a radiator that has lead paint on it, do not scrape or sand it at all. Instead, spray Rust-Oleum Rust Reformer on it, and then follow Steps When Painting, skipping steps 1, 3, and 4.

Plan on painting your radiator during the summer when you can turn it off and keep it off.

What Type Of Paint Should You Use?

You should use a type of paint that is rust-proof and is also resistant to high temperatures, up to at least 95° Centigrade. Rust-Oleum High Heat, Rust-Oleum High-Performance Enamel, and Sherwin-Williams Krylon High Heat are a few examples of such finishes. You may read on some sites that you should use latex- or alkyd-based primers and paints. Actually, the Rust-Oleum products mentioned above incorporate resins and compounds derived from latex and alkyd.

If you live in a climate which gets only moderately chilly in the cold season such that your radiator is not constantly on in the winter and is set to low or medium heat, you could get away with applying any old paint.

Can You Use Emulsion On A Radiator?

Although emulsions are not the ideal types of paints for radiators as high heat can cause them to discolour and even to crack and peel, premium emulsions can be used for painting radiators. The trick is to apply a topcoat of radiator clear-coat over the emulsion paint after it has completely dried. This will preserve the emulsion and protect it. One good choice is Ronseal Clear Enamel.

Steps When Painting

You will need to wear a dust mask at minimum when you scrape, and also paint, your radiator. However, it would be better to wear a proper half-face cover with filters.

Close all the valves and knobs and wait until the radiator has lost all its warmth. Keep the windows open if you can.

Ensure that children and pets, particularly boisterous ones, will not enter the room.

You can paint a radiator using spray paints or paint with a roller but for optimal results you should hand-paint with a brush.

If you intend to paint behind your radiator, see the appropriate section below.

1. First clean the radiator. First use a blower, especially at the bottom of the radiator in the ‘U’ concavities between flutes, to blow out all loose dust and particles. Then wash the radiator with a solution of a mild liquid detergent. Sponge it all over, using a wire Scotchguard sponge if necessary. Wipe it with an absorbent but fibre-free cloth, and then allow it to fully dry.

2. Spread a good-sized plastic sheet or newspapers on the floor under and around the radiator and put a large piece of cardboard behind the radiator to protect the wall. Stick masking tape around the valves and knobs; be careful not to get any paint on them.

3. Strip the old paint. First use a scraper at all the places that are peeling and chipping. Then finish off the job by scraping off the old paint with 40-grit sandpaper. (You will probably not be able to remove tightly-adhering paint and you do not need to.)

4. Sand the radiator with a fine-grit sandpaper, like 100-grit, to prepare the surface for priming and painting.

5. Apply a heat-resistant primer on the radiator. Primer may be sprayed on the radiator. Consult the product’s specs to determine drying time. As a general rule, allow at least 24 hours, preferably 48 hours, for the primer to dry.

6. Use a proper radiator paintbrush in which the brush-head is at an obtuse angle to the handle. While you may use a regulation 2-inch paintbrush to paint the obtruding fluting and mouldings and top surface of the radiator, the radiator paintbrush will prove indispensible in painting into the mouldings and concavities. Thoroughly shake the can of paint before opening it, and then stir it vigorously (having put it on the sheets you have spread on the floor!).

7. Begin by painting the top surface of the radiator. Move on to the sides, and then the bottom. These surfaces should be painted with free-flowing long strokes. Do not overload the brush otherwise the paint may run.

8. Proceed to the concavities and recessed areas with the special brush, as if doing detail-work painting. Then paint the protruding areas and mouldings. Apply paint lengthwise along the mouldings.

9. No matter what part of the radiator you are painting and which brush you are using, apply the paint such that each stroke slightly overlaps previous strokes and so that the developing coat is smooth and even.

Allow the paint dry. Then, after a few days, turn on the radiator at low-medium heat for a couple of hours with a window or two open on two consecutive days. Then your freshly-painted radiator will be ready to use in a sealed-shut room when you really need it.

Painting A Radiator With A Roller

If your radiator does not have pronounced moulding or flutes in high-relief, you could paint pretty much the whole radiator with a roller. Even in the worst case you could paint the top and sides with a roller for speed and convenience.

As your paint will probably be latex-based, use synthetic rollers. If you are not using a latex- or alkyd-based paint, use poly/wool rollers.

man painting radiator with a roller
A roller can make light work of the job

The trick is in choosing rollers of the correct widths – yes, rollers and widths in plural. To paint the top, sides, and bottom you can use a ‘regulation’ 10-centimetre roller. But to paint the front of the radiator, the ideal width will be dictated by the extent of the moulding, the closeness of the flutes, and the depth of the troughs. The more ‘relaxed’ these elements, the wider the roller than can be used; the more extreme these elements, the narrower must be the roller. Rollers as small as 1-inch (2.5 centimetres) are available and this should be narrow enough for most types of radiator mouldings and front areas.

You may read that pros use a bucket and screen when painting with a roller. However, this method is preferred when painting walls in a generally empty room for which you need a large volume of paint and where you might well jostle a tray, causing paint to slosh out. When painting a radiator, you need a limited quantity of paint and you can tuck a tray securely in a corner against the wall and right next to a side of the radiator.

From the section Steps When Painting, above, follow steps 1 through 4, and optionally step 5.

Use the 10-centimetre roller to paint the top, bottom, and sides. Dip the roller in the tray and roll it a rotation or two to load it but also gently squeeze it against the side of the tray to drain off the excess. Take long, lengthwise strokes with a degree of overlap. Dip and re-load the roller with paint as soon as the released paint becomes uneven or patchy.

When painting the front of the radiator with the smaller roller, take short vertical strokes. Paint from top to bottom; start with the recessed areas and troughs, and then move to the protruding areas and fluting.

Remember to lay sheets on the floor and to protect the wall behind the radiator before starting.

Using Spray Paint

It is best to spray paint your radiator after it is removed with the spray painting being done in your DIY workshop.

If you spray paint your radiator in-place, make sure to do a thorough job in covering up the wall behind the radiator, extending well past the top and sides, with plastic sheeting. Also cover the floor similarly.

Do not use artist-quality spray paint. Use a proper radiator spray paint such as Hammerite Radiator Enamel or Ronseal Quick Drying Spray.

From the section Steps When Painting, above, follow steps 1 through 4, and optionally step 5.

Wear gloves; these can be – or should be – light and thin. It is specially important to protect the valves and knobs with masking tape when spray painting. Finally, it is vitally important to wear a proper half-face cover with filters when using spray paint.

Vigorously shake the spray-paint can.

See Also

Apply the spray paint in longish sweeping motions at a distance of 10 to 15 centimetres. Spray the upper surface using a side-to-side motion. Spray the front using vertical sweeps. One coat will not be enough as you may observe a few gaps and uneven areas, and the colour will not be sufficiently deep. Let the first coat somewhat dry, say for five to ten minutes, and then apply a second coat. If necessary or desirable, repeat once more.

How To Paint Behind A Radiator Without Removing It

If you intend to paint behind your radiator, do so before painting the radiator itself. First, cover up the radiator all round using Saran wrap or cling film.

Painting behind a radiator without removing it is a tricky business as regulation painting tools are typically neither narrow enough nor long enough. You could try using the smallest roller or tie a radiator painbrush to a thin rod. Long-handled mini rollers are available and if these fit behind your radiator then you’ll have an easy time of painting behind it.

However, if the space between the rear of the radiator and the wall is too tight you may well have to improvise by making your own painting tool. Here’s our version.

Get a couple of long barbecuing skewers or open up a wire coat hanger so that you get a ‘rod’ that is both thin enough and long enough. Bend back about 5 centimetres of the ‘rod’ on itself so that that length is about twice the thickness of the rest of the ‘rod.’ Attach a longish strip of a sponge of about half-a-centimetre in thickness to this end of the rod. Do so by tightly wrapping it around so that the sponge’s edges press flat against each other, and staple them tightly along the length. Trim the excess, i.e. the ‘lips’ fore of the staples. Use a one-centimetre cloth sticking tape to tightly tape the top and bottom edges of the rolled-round sponge to the rod so that it does not slide along the rod.

Be careful not to let the stapled ends even touch the wall let alone paint with that side, otherwise it will scratch and spoil the finish.

After you’re done, remove the cling film with care so that it does not touch the freshly-painted wall or double back on iself and possibly daub the radiator. Best of all, wait until all the paint has completely dried and then remove the cling film.

Painting A Rusty Radiator

In order to paint a rusty radiator you will need to take special steps and devote additional time to removing rust and flakes, and in prepping the radiator.

First, inspect how bad the rust and corrosion is. If the radiator is deeply pitted and eaten into, you may be well advised not to work on it but seek a professional opinion or leave it up to the pros.

Do your prepping and painting in the summer when the radiator is cold and will not be needed.

Close all valves and knobs.

To prep a rusty radiator, collect the following: a spatula, 80-grit sandpaper, a wire brush, white vinegar, lemon juice, WD-40, and Rust-Oleum Rust Reformer.

Put on a proper half-face cover with filters and ensure that children (and, preferably, adults as well) will not enter the room during your rust-removal job.

First use the sandpaper and wire brush to scrape off loose flakes and rust. To detach stubborn bits use the spatula but do not exert excessive force.

Next, use the white vinegar and lemon juice. Liberally sprinkle or splatter both on trouble spots. Alternatively, spray WD-40 on the trouble spots. Allow the vinegar-and-lemon juice to ‘work’ for an hour; the WD-40 for 15 to 20 minutes. Then use the wire brush and spatula to scrape off the dissolved, semi-solid rust.

On whatever rusted or irrecoverable spots that remain, spray some Rust-Oleum Rust Reformer. Shake the can thoroughly before using it. This product will convert rusted metal into a smooth, paintable surface. Avoid the temptation to take a short-cut and spray it over an entire rusty radiator because a radiator (a) becomes very hot, and, (b) it is indoors in a sealed-shut room!

How To Re-Paint A Radiator

To re-paint a radiator, you need to strip and sand it first. Simply follow steps 3 and 4 in section Steps When Painting, above.

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